CivilEng doi: 10.3390/civileng5010015
Authors: Diwakar KC Bhim Kumar Dahal Harish Dangi
Orthotropic steel bridge decks (OSDs) are very popular all over the world because of the low dead load, high stiffness in the longitudinal direction, high strength ratio to weight, and can be used in various types of bridges. The life of these bridges is affected by fatigue cracks in different portions. One of major areas where the fatigue cracks appear in these bridges is rib-to-deck connection. In this research finite element analysis is carried out by using ABAQUS/CAE 2022 software to determine the ways to increase the fatigue life at rib to deck connection in OSDs. In the first part, smaller models are simulated; stress concentration is analyzed and hot spot stress (HSS) is calculated according to International Institute of Welding (IIW) and Det Norske Veritas (DNV) recommendations. In the second part, a parametric analysis is carried out to analyze the effect of weld penetration, thickness of deck, thickness of rib and rib to deck connection type. In the third part, simulation of models similar to the real field is carried out to determine whether the double welded connections are better than single welded connections. Different models are analyzed for different load cases like single wheel load, double wheel load and also the position of the wheels is changed. The boundary conditions are changed to analyze whether the boundary condition has any significant effect on the result obtained. It is found that thicker decks, thinner ribs, and low penetrated welded connections reduce the stress concentrations at rib to deck connections which ultimately increase fatigue life. Among the parameters examined, deck thickness is the most important parameter. It is found that the percentage of stress increase with percentage decrease in deck thickness follows a power relation. The overall fatigue life of double welded connection is excepted to be lower since the stress concentration is maximum at the weld toe at deck on the outer side of the closed stiffener; however, if the cracks initiate on the inner side of closed stiffener, the cracks at the weld root of single welded connection can propagate much rapidly than the cracks initiating on the inner side of the closed stiffener at the weld toe, thereby reducing the fatigue life of the single-welded specimen significantly.
]]>CivilEng doi: 10.3390/civileng5010014
Authors: Reihaneh Samsami
Despite the subjective and error-prone nature of manual visual inspection procedures, this type of inspection is still a common process in most construction projects. However, Automated Construction Inspection and Progress Monitoring (ACIPM) has the potential to improve inspection processes. The objective of this paper is to examine the applications, challenges, and future directions of ACIPM in a systematic review. It explores various application areas of ACIPM in two domains of (a) transportation construction inspection, and (b) building construction inspection. The review identifies key ACIPM tools and techniques including Laser Scanning (LS), Uncrewed Aerial Systems (UAS), Robots, Radio Frequency Identification (RFID), Augmented Reality (AR), Virtual Reality (VR), Computer Vision (CV), Deep Learning, and Building Information Modeling (BIM). It also explores the challenges in implementing ACIPM, including limited generalization, data quality and validity, data integration, and real-time considerations. Studying legal implications and ethical and social impacts are among the future directions in ACIPM that are pinpointed in this paper. As the main contribution, this paper provides a comprehensive understanding of ACIPM for academic researchers and industry professionals.
]]>CivilEng doi: 10.3390/civileng5010013
Authors: Adriano G. S. Azevedo Juan Camilo Adrada Molano Igor Parente Taís O. G. Freitas Aires Camões Paulina Faria Holmer Savastano
This article analyzes the effect of the rehydration method on the physical–mechanical properties of accelerated carbonation-cured magnesium-based fiber cement boards. The rehydration process of the boards was analyzed in conjunction with the analysis of the pre-curing time before accelerated carbonation (24, 48, and 72 h before carbonation), resulting in eight different curing parameters used in this investigation. The physical–mechanical performance and microstructural characteristics of magnesium oxysulfate boards before and after carbonation were investigated by water absorption, apparent porosity, and bulk density using the four-point bending test, X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy. According to the results, the accelerated carbonation process improved the mechanical properties of the boards. The samples that carbonated after 48 h showed a higher modulus of rupture. The rehydration process of the composites before carbonation led to enhancements in the pre-cured boards for 48 and 72 h, demonstrating that carbonation occurred more effectively after water rehydration. The mechanical improvements were associated with the formation of hydration products, which preferentially formed in the pores and voids of the fiber cement matrix. These carbonation products altered the physical properties of the composites, increasing the density of the boards and reducing the void volume. The decomposition of the formed carbonates was confirmed by thermogravimetric analysis, which indicated that the rehydration process favored the carbonation of the composites.
]]>CivilEng doi: 10.3390/civileng5010012
Authors: Iurii Vakaliuk Silke Scheerer Manfred Curbach
In the case of solid slabs made of reinforced concrete that are usually subjected to bending, large areas of the structure are stressed well below their load-bearing capacity. Contrary to this are shell structures, which can bridge large spans with little material if designed according to the force flow. To improve the efficiency of ceiling slabs, we want to utilize the shell load-bearing behavior on a smaller scale by resolving the solid interior accordingly. In order to study a wide range of such constructions virtually, a parametric multi-objective simulation environment is being developed in an ongoing research project. The basic analysis approaches that were implemented are presented in this paper. The basic workflow, the used programs and material models, and their calibration on the tests on textile-reinforced concrete (TRC) samples are described.
]]>CivilEng doi: 10.3390/civileng5010011
Authors: Syed Jahanzaib Shah Asad Naeem Farzad Hejazi Waqas Ahmed Mahar Abdul Haseeb
The demand for lightweight aggregates in concrete compositions for diverse structural and non-structural applications in contemporary building construction has increased. This is to achieve a controllable low-density lightweight concrete, which reduces the overall structural weight. However, the challenge lies in achieving an appropriate strength in lightweight concrete while maintaining a lower unit weight. This research aims to evaluate the performance of lightweight concrete by integrating expanded polystyrene (EPS) as a partial replacement for coarse aggregate. Test specimens were cast by blending EPS with coarse aggregate at varying proportions of 0%, 15%, 30%, and 45%, while maintaining a constant water-to-binder ratio of 0.60. To enhance the bonding and structural capabilities of the proposed lightweight concrete mixes, reinforcement with 2% and 4% steel fibers by volume of the total concrete mix was incorporated. Silica fume was introduced into the mix to counteract the water hydrophobicity of EPS material and enhance the durability of lightweight concrete, added at a rate of 10% by weight of cement in all specimens. A total of 60 samples, including cylinders and beams, were prepared and cured over 28 days. The physical and mechanical properties of the lightweight EPS-based concrete were systematically examined through experimental testing and compared against a standard concrete mix. The analysis of the results indicates that EPS-based concrete exhibits a controllable low density. It also reveals that incorporating reinforcement materials, such as steel fibers, enhances the overall strength of lightweight concrete.
]]>CivilEng doi: 10.3390/civileng5010010
Authors: Esmerald Filaj Enio Deneko Reza Moezzi Mohammad Gheibi Andres Annuk
Vertical shortening, a phenomenon inherent to concrete structures, plays a key role in the quality and safety of construction, particularly in tall reinforced concrete buildings. This behavior is intrinsically linked to the time-dependent properties of concrete, encompassing both creep and shrinkage. Neglecting these aspects, especially when non-uniformly distributed, can give rise to various structural issues, including partition distress, overloading, and potential cracking in horizontal elements. This paper delves into the principal factors influencing vertical shortening and presents a rigorous approach to their evaluation, treating creep and shrinkage as critical parameters. The investigation employs two illustrative case studies: the first revolves around a 15-story reinforced concrete building with single columns supporting tributary areas at various levels, acting as a calibration case; the second encompasses a 30-story reinforced concrete structure employing a dual system, providing a broader perspective applicable to three-dimensional structures. A diverse array of analyses is conducted, incorporating considerations for concrete’s linear and nonlinear behavior as well as the impact of construction stages. Our findings reveal that vertical shortening is directly proportional to the building’s height and inversely related to concrete strength, longitudinal reinforcement ratios, member dimensions, volume-to-surface ratios, age of the structure upon load application, and relative humidity. Consequently, precise assessments of differential shortening effects are paramount. The utilization of staged construction analysis and time-dependent effects is recommended as the most suitable approach for evaluating vertical shortening effects.
]]>CivilEng doi: 10.3390/civileng5010009
Authors: Yikai Gong Martin Noël
The finite element method was used to study the feasibility of concrete-filled, fiber-reinforced polymer tubes (CFFTs) for small-scale wind turbine towers in remote areas. Although CFFTs have been successfully employed for a variety of structural applications, their use for wind turbine towers is novel and has yet to be investigated in detail. The objective of the study was to identify, for the first time, the most important parameters for design and compare the behavior of CFFT towers versus conventional steel and concrete towers. The model was first validated using experimental results reported in the literature followed by a series of parametric studies to evaluate the importance of several key parameters. In the first phase, the effect of different geometric properties (taper and concrete filling ratio) and reinforcement configurations (FRP laminate configuration, steel reinforcement ratio, and prestressing level) were investigated for cantilever tower models with concentrated lateral loads. A 10 m high CFFT wind turbine tower model was subsequently modeled and studied under different loading configurations. The influence of the height-to-diameter (h/D) ratio on cantilever CFFT models was also studied and a conservative preliminary design that can be refined for specific turbine systems and wind conditions was adopted using the h/D ratio. The CFFT tower model was compared to concrete and steel tubular models with similar geometry to study the advantages of CFFT towers and showed that CFFTs can be an efficient alternative.
]]>CivilEng doi: 10.3390/civileng5010008
Authors: Anton Chepurnenko Vasilina Turina Vladimir Akopyan
Artificial neural networks (ANN) have a great promise in predicting the load-bearing capacity of building structures. The purpose of this work was to develop ANN models to determine the ultimate load of eccentrically compressed concrete-filled steel tubular (CFST) columns of circular cross-sections, which operated on the widest possible range of input parameters. Short columns were considered for which the amount of deflection does not affect the bending moment. A feedforward network was selected as the neural network type. The input parameters of the neural networks were the outer diameter of the columns, the thickness of the pipe wall, the yield strength of steel, the compressive strength of concrete and the relative eccentricity. Artificial neural networks were trained on synthetic data generated based on a theoretical model of the limit equilibrium of CFST columns. Two ANN models were created. When training the first model, the ultimate loads were determined at a given eccentricity of the axial force without taking into account additional random eccentricity. When training the second model, additional random eccentricity was taken into account. The total volume of the training dataset was 179,025 samples. Such a large training dataset size has never been used before. The training dataset covers a wide range of changes in the characteristics of the pipe metal and concrete of the core, pipe diameters and wall thicknesses, as well as eccentricities of the axial force. The trained models are characterized by high mean square error (MSE) scores. The correlation coefficients between the predicted and target values are very close to 1. The ANN models were tested on experimental data for 81 eccentrically compressed samples presented in five different works and 265 centrally compressed samples presented in twenty-six papers.
]]>CivilEng doi: 10.3390/civileng5010007
Authors: Raheb Mirzanamadi Erik Nyberg Peter Torstensson Yvonne Andersson-Sköld
Rail transport is expected to become a key component in the development of a long-term sustainable transport system. The planning, construction, operation, and maintenance of railway infrastructure are crucial in this effort. Hence, it is essential to ascertain that the railway infrastructure withstands and is adapted to extreme weather conditions and climate change. This study focuses on evaluating climate adaptation measures for lateral track buckling in Sweden. Through a literature review and interview with an expert at Swedish Transport Administration, it is highlighted that the maintenance status of railway infrastructure plays a significant role in the occurrence of lateral track buckling. According to the expert, inadequate track maintenance is the primary cause of lateral track buckling rather than weather variables like air temperature. The interview also clarifies that the chain of events related to the handling of track buckling is mainly initiated by the observation of a discrete lateral irregularity by a train driver, whereupon the train dispatcher at the traffic management center stops traffic until the location in the track has been inspected by a track entrepreneur. During the inspection, up to half of the observed cases of track buckling turn out to be false.
]]>CivilEng doi: 10.3390/civileng5010006
Authors: Hasan Ali Abbas Duaa Al-Jeznawi Musab Aied Qissab Al-Janabi Luís Filipe Almeida Bernardo Manuel António Sobral Campos Jacinto
Shear wave velocity (Vs) is a critical parameter in geophysical investigations, micro-zonation research, and site classification. In instances where conducting direct tests at specific locations is challenging due to equipment unavailability, limited space, or initial instrumentation costs, it becomes essential to estimate Vs directly, using empirical correlations for effective site characterization. The present review paper explores the correlations of Vs with the standard penetration test (SPT) for geotechnical site characterization. Vs, a critical parameter in geotechnical and seismic engineering, is integral to a wide range of projects, including foundation design and seismic hazard assessment. The current paper provides a detailed analysis of the key findings, implications for geotechnical engineering practice, and future research needs in this area. It emphasizes the importance of site-specific calibration, the impact of geological background, depth-dependent behavior, data quality control, and the integration of Vs data with other geophysical methods. The review underlines the continuous monitoring of Vs values due to potential changes over time. Addressing these insights and gaps in research contributes to the accuracy and safety of geotechnical projects, particularly in seismic-prone regions.
]]>CivilEng doi: 10.3390/civileng5010005
Authors: Michael C. Okika Andre Vermeulen Jan-Harm C. Pretorius
Interface risks are inherent in every construction project from start to finish. Identifying and managing these risks effectively in every project phase is crucial for actualising project objectives. This paper shows a comprehensive framework showing several relationships between project stakeholders and how the interface risks between them that influence project execution are identified and managed for the overall construction project success. Firstly, a literature review on interfaces and interface risks and a discussion on how organisations managed interface risks were carried out, and secondly, the collection of quantitative data was conducted by means of structured online questionnaires. The sample consisted of 205 construction project professionals who were selected randomly. This group included individuals with various roles in the construction industry. The data were analysed using descriptive statistical methods, including factor analysis, reliability assessment, and calculations of frequencies and percentages. The results showed all the factors, work cultures, and organisational approaches that influence interface risk management and ways to identify and manage interface risks effectively. Effective stakeholder management is crucial for effective interface risk management since many interface risks are created by the numerous stakeholders involved in the project and the proposed frameworks will effectively mitigate the consequences and causes of interface risks. Effectively mitigating these risks involves effective stakeholder management, building information modelling volume strategy, and creating a virtual construction model during the construction phase; in addition, construction supply chain risks must be carefully identified during the interfaces establishment stages; interface risks must be carefully identified during the conceptualisation; and the planning, construction, and execution stages and standard methods and procedures must be defined to effectively identify and manage interface risks as the occur in the project lifecycle plus implementing the proposed risk mitigation frameworks.
]]>CivilEng doi: 10.3390/civileng5010004
Authors: Costas A. Anagnostopoulos Vasilios Aggelidis
The aim of this research was to undertake laboratory testing to investigate the beneficial effects of epoxy resin grouts on the physical and mechanical properties of sands with a wide range of granulometric characteristics. Six sands of different particle size and uniformity coefficients were grouted using epoxy resin solutions with three ratios of epoxy resin to water (3.0, 2.0 and 1.5). A set of unconfined compressive strength tests were conducted on the grouted samples at different curing periods and a set of long-term unconfined compressive creep tests in dry and wet conditions after 180 days of curing were also carried out in order to evaluate the development of the mechanical properties of the sands, as well as the impact of water on them. The findings of the investigation showed that epoxy resin resulted in appreciable strength values in the specimens, especially those of fine sands or well graded sands, grouted with the different epoxy resin grouts. Whilst the higher compressive strength and elastic modulus values at the age of 180 days were obtained for the finer sand, which ranged from 2.6 to 5.6 MPa and 216 to 430 MPa, respectively, the lower compressive strength and elastic modulus values were attained for the coarser sand with low values of the coefficient of uniformity, which varied from 0.68 to 2.2 MPa and 75 to 185 MPa, respectively. Moreover, all grouted sands showed stable long-term creep behaviour, with high values of the creep limit ranging from 67.5 to 80% of compressive strength. The presence of water had a negative marginal effect in the majority of the grouted specimens. In terms of physical properties, the permeability and porosity were estimated. The permeability of fine sands or well graded sands was decreased by two to four orders of magnitude. Using laboratory results and regression analysis, three mathematical equations were developed that relate each of the dependent variables of compressive strength, elastic modulus and coefficient of permeability to particular explanatory variables.
]]>CivilEng doi: 10.3390/civileng5010003
Authors: Othon Moreira Aires Camões Raphaele Malheiro Carlos Jesus
The use of waste as supplementary cementitious materials (SCMs) in concrete is already widespread, with glass waste being an increasingly used option. The utilization of glass waste as a partial substitute for cement in small proportions has shown satisfactory outcomes. Nevertheless, substituting cement in high proportions requires further investigation. Experimental research was carried out on the mechanical and durability properties of concrete with the replacement of cement by glass powder (GP), at a high volume equal to 50%. Binder content (cement plus GP) varied from 300 to 500 kg/m3. The results are promising regarding the use of the high volume of GP in high-performance concretes. The specimens with 500 kg/m3 of binder (50% of which was GP-G250) achieved almost 55 MPa at 28 days. The specimen with the lowest resistance was G150, with 32 MPa. This result may be related to the high pozzolanic activity index of the used GP. The specimens with GP showed satisfactory performance regarding chloride migration, with diffusion coefficients always below those of the reference specimens. The G250 concrete showed a reduction of 58%. Regarding open porosity, concretes with 50% GP had a lower porosity than the reference concretes. The smallest reduction (21%) occurred in the G150 concrete. The reduction in porosity provided by the fineness of the GP may be the main cause of this high performance. Concerning capillary absorption, the GP concretes have a reduction that varies between 47% for G150 and 67% for G250. This fact may be related to the existence of a larger quantity of larger-sized capillary pores in the reference concretes.
]]>CivilEng doi: 10.3390/civileng5010002
Authors: Zeinab A. Younis Maryam Nazari
Tire-derived aggregate concrete (TDAC), or rubberized concrete, is gaining ground as an eco-friendly option in civil engineering. By substituting traditional coarse aggregates with recycled rubber tires, TDAC offers a greener choice with excellent energy absorption capabilities. This leads to robust structures and reduced upkeep expenses. Nonetheless, TDAC’s lower strength than regular concrete requires a delicate balance between energy absorption and strength. This study investigates two enhancements to TDAC performance: (a) the impact of sodium hydroxide (NaOH) solution pretreatment and SikaLatex bonding agent addition on TDAC’s compressive strength, and (b) the use of varying water–cement ratios and superplasticizer to enhance TDAC’s mechanical properties. This study involves concrete cylinder compression tests and the creation of strength estimation equations. Results show that NaOH-treated tire-derived aggregate (TDA) boosts workability, increasing slump by 4.45 cm (1.75 in), yet does not significantly enhance compressive strength, causing a 34% reduction. Conversely, combining NaOH pretreatment with Sikalatex bonding agent enhances workability by 28% and boosts compressive strength by 21% at the same water-cement ratio. To optimize performance, it is advised to employ modified TDA concrete with a water–cement ratio under 0.34 and superplasticizer. These findings highlight the potential of modified TDA concrete in sustainable and seismic-resistant designs.
]]>CivilEng doi: 10.3390/civileng5010001
Authors: Michelle Siu Zhi Lee Nobuyoshi Yabuki Tomohiro Fukuda
Building inspections are critical for ensuring compliance with construction standards, but conventional methods, often manual, face challenges in efficiency and consistency due to heavy reliance on human factors. Mixed-reality (MR) solutions could potentially address these challenges as they reportedly achieve good efficiency and accuracy in mapping indoor environments. This research investigates the potential of utilizing a wearable MR device to perform dimensional checks through edge computing of device sensor data, reducing the reliance on human factors. The accuracy of MR-computed dimensions against ground truth data for common building elements was assessed. Results indicate that MR-computed dimensions align well with ground truth for simple objects, but complex objects such as staircases presented limitations in achieving satisfactory results. If-then checks applied to MR-computed dimensions for automated detection of non-compliance were successfully experimented. However, automating compliance checks for standards with complex rules requires further investigation. This research sheds light on the potential of MR solutions for building inspections and highlights future research directions to enhance its applicability and effectiveness in the construction industry.
]]>CivilEng doi: 10.3390/civileng4040069
Authors: Amr E. Abdallah Shukai Chen Ehab F. El-Salakawy
Wooden utility poles are vulnerable to degradation and decay, which requires maintenance or replacement. The strengthening and retrofitting techniques for wooden poles are either prone to corrosion or encountering installation difficulties. However, the use of sprayed fiber-reinforced polymer (FRP) composites seems to be a viable solution as it has proven its efficiency and applicability for reinforced concrete members and connections. This study includes a comprehensive experimental program where the mechanical properties of the sprayed-glass FRP (GFRP) composite was evaluated in terms of tensile, compressive and shear strength, in addition to its bond strength to wood and confinement efficiency. Afterwards, the results of the material testing phase were implemented on full-scale old utility poles to evaluate their structural performance with varying composite thicknesses and sprayed zone lengths. The behavior of the retrofitted poles reflected remarkable effectiveness for the sprayed-GFRP composite and highlighted the need for a design model for the optimum length for the sprayed zone. Two simplified analytical models were introduced which predicted the failure loads and locations for the tested poles and estimated the required length for the retrofitted zone, which all agreed well with the experimental results of the tested poles.
]]>CivilEng doi: 10.3390/civileng4040068
Authors: Narek Galustanian Alaa El-Sisi Asmaa Amer Eman Elshamy Hilal Hassan
The need for openings in RC structures has increased, but their presence significantly affects the performance and strength of the structures. While small openings can be managed with additional reinforcement, dealing with large openings in reinforced or pre-stressed concrete members is challenging due to the lack of technical information and specific guidelines. This research provides an up-to-date overview of RC beam–column joints that incorporate web openings and evaluates appropriate strengthening methods. The research discusses the classification of openings in RC beams, considering factors such as size and shape. Additionally, it examines the failure modes of RC beams in relation to flexural and shear behavior when web openings are present. The research also provides a comprehensive review of various strengthening techniques, outlining their advantages and disadvantages. In conclusion, larger openings in beams result in reduced strength, while increasing loads lead to higher deflection, strain, and cracking until failure. Openings are classified as small or large based on their impact on beam behavior. Multiple smaller openings are preferred over a single large opening when size becomes excessive. Optimal placement is in the middle of the section to ensure adequate concrete coverage for the chords. Sufficient concrete and depth are essential for ultimate compression during bending and effective shear reinforcement.
]]>CivilEng doi: 10.3390/civileng4040067
Authors: Pedro Martin-Moreta Susana Lopez-Querol Juan P. Martín-Vide
Bedload transport in a river is a deeply analyzed problem, with many methodologies available in the literature. However, most of the existing methods were developed for reaches of rivers rather than for confluences and are suitable for a particular type of material, which makes them very inaccurate in cases where the sediments are comprised of a mix of different types of soil. This study considers the effect of two different bed sediment sizes, gravel and sand, in relation to bed load transport in a confluence. Five well-known and validated equations (namely Meyer-Peter and Müller, Parker + Engelund and Hansen, Ackers and White, and Yang) are applied to the case study of the Tagus–Alberche rivers confluence (in Talavera de la Reina, Spain), where main and tributary rivers transport different materials (sand and gravel). Field works in the area of the confluence were conducted, and a set of alluvial samples were collected and analyzed. The previously mentioned methods were employed to analyze the geomorphology in the confluence area and downstream of it under different flooding scenarios, concluding different trends in terms of deposition/erosion in the area under historic flooding scenarios. When the trends show erosion, all methods are very consistent in terms of numerical predictions. However, the results present high disparity in the estimated values when the predictions suggest deposition, with Parker + Engelund and Hansen yielding the highest volumes and Meyer-Peter and Müller the lowest (the latter being around 1% of the former). Yang and Ackers and White predict deposits in the same range in all cases (around 15% of Parker and Engelund Hansen). Yang’s formula was found to be suitable for the confluences of rivers with different materials, allowing for the estimation of sediment transport for different grain sizes. The effect of different flow regimes has been analyzed with the application of Yang’s formula to the Tagus-Alberche confluence.
]]>CivilEng doi: 10.3390/civileng4040066
Authors: Youssef El Bitouri
The structural build-up of cementitious materials is the subject of more and more attention since it conditions several processes such as formwork pressure and multi-layer casting. However, this phenomenon originating from flocculation and chemical changes is complex and its reversibility is not clearly elucidated. The aim of this paper is to examine the effect of temperature on the reversibility of structural build-up. The results show that irreversible structural build-up remains negligible despite a rise in temperature. It represents between 0.5–7.3% of the total structural build-up. The addition of SCMs allows for a decrease in this irreversible structural build-up. Therefore, a large part of the chemical contribution is expected to be reversible. The effect of temperature can be explained by the increase in the dissolution rate leading to an increase in flocculation and to the bridging effect induced by early hydrates. Finally, the results suggest that the interparticle distance could be the key parameter governing the irreversibility of structural build-up.
]]>CivilEng doi: 10.3390/civileng4040065
Authors: Georgios Xekalakis Petros Christou Dimitris Pitilakis Nicholas Kyriakides
Earthen structures made of adobe bricks are complex systems that making the identification of their behavior difficult, especially when they have to sustain lateral forces such as seismic forces. This paper presents a numerical investigation for the assessment of the structural response of unreinforced adobe masonry structures and how the installation of wooden ring beams contributes to their overall resistance. In the framework of the numerical investigation, finite element models were created to simulate the response of an adobe building with and without the presence of wooden ring beams. The test building is located in Cyprus, in the South Eastern Mediterranean region which is a seismic area. The material properties used in this study were found in the literature and were based on experimental data for local materials. The models were subjected to earthquake loads, performing time history analyses for the calculation of pertinent displacements and stresses. The findings indicate that integrating wooden ring beams reduces the fundamental period by 6% and modifies the building’s seismic behavior. This modification is evident not just in the magnitude of the stresses but also in their distribution, leading to a stratified stress profile. Peak stresses are primarily concentrated around the ring beams.
]]>CivilEng doi: 10.3390/civileng4040064
Authors: Tarek N. Salem Ayman El-Zohairy Ahmed M. Abdelbaset
Steel storage tanks are widely used in different fields. Most of these tanks contain hazardous materials, which may lead to disasters and environmental damage for any design errors. There are many reasons which cause the failure of these tanks such as excessive base plate settlement, shear failure of soil, liquid sloshing, and buckling of the tank shell. In this study, five models of above-ground steel storage tanks resting over different types of clay soils (medium-stiff clay, stiff clay, and very stiff clay soils) are analyzed using the finite element program ADINA under the effect of static and dynamic loading. The soil underneath the tank is truly simulated using a 3D solid (porous media) element and the used material model is the Cam-clay soil model. The fluid in the tank is modeled depending on the Navier–Stokes fluid equation. Moreover, the earthquake record used in this analysis is the horizontal component of the Loma Prieta Earthquake. The analyzed tanks are circular steel tanks with the same height (10 m) and different diameters (ranging from 15 m to 40 m). The soil under the tanks has a noticeable effect on the dynamic behavior of the studied tanks. The tanks resting over the medium-stiff clay (the weakest soil) give a lower permanent settlement after the earthquake because of its low elastic modulus which leads to the absorption of the earthquake waves in comparison to the other types of soil. There are 29.6% and 35.6% increases in the peak dynamic stresses under the tanks in the cases of stiff clay and very stiff clay soils, respectively. The maximum values of the dynamic vertical stresses occur at a time around 13.02 s, which is close to the peak ground acceleration of the earthquake.
]]>CivilEng doi: 10.3390/civileng4040063
Authors: Ammar Alzarrad Matthew Miller Sudipta Chowdhury James McIntosh Tyler Perry Ryan Shen
The construction industry has witnessed a surge in heat-related accidents alongside rising summertime temperatures, exposing workers to potential injuries. The absence of specific heat stress standards by the Occupational Safety and Health Administration (OSHA) underscores the urgent need for more comprehensive and interactive educational materials to prevent such incidents in construction projects. This study proposes the adoption of an interactive Virtual Reality (VR) application to offer construction workers realistic and effective training, mitigating heat-related injuries. During the training sessions, VR headsets were utilized to immerse workers in two lifelike scenarios: (1) Addressing self-care during heat exhaustion; (2) Assisting a coworker experiencing heat exhaustion. A case study evaluated the effectiveness of the proposed VR training for 82 construction workers from two companies. Company A had traditional training, while Company B used VR training. Both groups took pre- and post-assessment surveys with six questions. The pre-assessment found no significant knowledge difference between the groups. After training, VR showed a significant reduction in incorrect answers compared to traditional training. Statistical tests confirmed the superiority of VR training (p-value = 0.00152 < 0.05), suggesting its effectiveness in preventing heat-related injuries in construction compared to traditional training methods.
]]>CivilEng doi: 10.3390/civileng4040062
Authors: Hojin Cho Jaehak Park Kyungsu Park
A squat is a type of fatigue defect caused by short-wavelength rotational contact; if squats are detected early, the maintenance cost of the track can be effectively reduced. In this paper, a method for the early detection of squats is presented based on ABA (axle box acceleration) and frequency signal processing techniques. To increase the measurement sensitivity for the squat, ABA was used to measure the longitudinal vibration. Compared to vertical ABA, longitudinal ABA does not include vibrations from rail fasteners and sleepers, so it is possible to effectively measure the vibration signal in relation to the impact of the rail. In this paper, vibration data were measured and analyzed by installing a 3-axis accelerometer on the wheel axle of the KTX; squat signals were more effectively extracted using the longitudinal vibration measurement presented above. The algorithm to detect the position of squats was developed based on wavelet spectrum analysis. This study was verified for the section of a domestic high-speed line, and as a result of conducting field verification for this section, squats were detected with a hit rate of about 88.2%. The main locations where the squats occurred were the rail welds and the joint section, and it was confirmed that unsupported sleepers occurred at locations where the squats occurred in some sections.
]]>CivilEng doi: 10.3390/civileng4040061
Authors: Nawaf K. Alsohiman Wael Alattyih Husnain Haider
One common theme in the international construction sector is project variation, which influences project outcomes. This study argued that variation could occur during the lifecycle of a construction project that might affect the contracted project success criteria (PSC), including cost, time, quality, or scope parameters. These variations can originate from the owner, consultant, contractor, or external factors. The construction industry is a critical partner in operationalizing and implementing the long-term sustainability objectives of Vision 2030 in the Kingdom of Saudi Arabia (KSA). The present study identified 18 factors that can cause variation orders by the owners of construction projects and evaluated them using statistical and fuzzy-based methods. To estimate the influence of variation orders on PSC in Saudi Arabia, over 70 experienced professionals, including project managers (58%), engineers (26%), and strategic management officers (16%) working in the construction industry evaluated the identified factors through a questionnaire survey. A 1–4 Likert scale, no impact (1) to high impact (4) on PSC, was used to rank identified factors. Analysis of variance and Tukey tests found no statistically significant difference between the respondents’ opinions. Out of the four PSC, cost and time with 14 out of 18 factors obtaining scores higher than “3” superseded quality with seven and scope with six factors. The Fuzzy Synthetic Evaluation identified inadequate planning, managerial corruption, the method of lowest bidding procurement, the inadequate experience of owner’s staff, additional work added by the owners, delayed starts, mode of financing and payments, and public works contract rigidity as the most critical factors affecting PSC of the construction projects in the view of participated stakeholders. Conversely, shortening the project period, long intervals between design and project initiation, and restrictions against foreign companies were identified as the least important factors. The study helps stakeholders achieve long-term sustainability by focusing on the top-ranked factors in KSA’s construction industry and the Gulf Region with similar working environments, rules, and regulations.
]]>CivilEng doi: 10.3390/civileng4040060
Authors: Jonny Nilimaa Yaser Gamil Vasiola Zhaka
This study provides a comprehensive review of the engineering challenges of formwork in concrete construction. The paper investigates different formwork systems, their design based on form pressure, and the difficulties of form stripping. Alternative binders are gaining more and more interest by opening new opportunities for sustainable concrete materials and their impact on form pressure and concrete setting is also investigated in this paper. The discussion involves several engineering challenges such as sustainability, safety, and economy, while it also explores previous case studies, and discusses future trends in formwork design. The findings pinpoint that choosing an appropriate formwork system depends significantly on project-specific constraints and that the development of innovative materials and technologies presents significant benefits but also new challenges, including the need for training and regulation. Current trends in formwork design and use show promising possibilities for the integration of digital technologies and the development of sustainable and ‘smart’ formwork systems. Continued research within the field has the possibility to explore new formwork materials and technologies, which will contribute to the implementation of more effective and sustainable practices in concrete construction.
]]>CivilEng doi: 10.3390/civileng4040059
Authors: Nicola Baldo Fabio Rondinella Fabiola Daneluz Pavla Vacková Jan Valentin Marcin D. Gajewski Jan B. Król
Stiffness modulus represents one of the most important parameters for the mechanical characterization of asphalt mixtures (AMs). At the same time, it is a crucial input parameter in the process of designing flexible pavements. In the present study, two selected mixtures were thoroughly investigated in an experimental trial carried out by means of a four-point bending test (4PBT) apparatus. The mixtures were prepared using spilite aggregate, a conventional 50/70 penetration grade bitumen, and limestone filler. Their stiffness moduli (SM) were determined while samples were exposed to 11 loading frequencies (from 0.1 to 50 Hz) and 4 testing temperatures (from 0 to 30 °C). The SM values ranged from 1222 to 24,133 MPa. Observations were recorded and used to develop a machine learning (ML) model. The main scope was the prediction of the stiffness moduli based on the volumetric properties and testing conditions of the corresponding mixtures, which would provide the advantage of reducing the laboratory efforts required to determine them. Two of the main soft computing techniques were investigated to accomplish this task, namely decision trees with the Categorical Boosting algorithm and artificial neural networks. The outcomes suggest that both ML methodologies achieved very good results, with Categorical Boosting showing better performance (MAPE = 3.41% and R2 = 0.9968) and resulting in more accurate and reliable predictions in terms of the six goodness-of-fit metrics that were implemented.
]]>CivilEng doi: 10.3390/civileng4040058
Authors: Rajat Agrawal Suraj Kumar Singh Saurabh Singh Deepak Kumar Prajapat Sharma Sudhanshu Sujeet Kumar Bojan Đurin Marko Šrajbek Gordon Gilja
India is confronted with the substantial issue of plastic debris due to the absence of an efficient waste management infrastructure. Recycled plastic has the potential to enhance various construction materials, such as roofing tiles, paving blocks, and insulation. The aforementioned materials possess notable attributes such as high strength, low weight, and exceptional resistance to extreme temperatures and humidity. The objective of this study is to ascertain feasible alternatives for manufacturing road paver blocks utilizing plastic waste (Polyethene terephthalate (PET)), and M-sand (stone dust). Three variations of a discarded plastic cube measuring 150 mm × 150 mm × 150 mm were prepared for the experiment. The experimental findings indicated that a ratio of 1:4 was determined to be the most effective in achieving the desired level of compressive strength. I-section road and brick paver blocks were produced as an alternative to the traditional concrete ones. Compressive strength tests were performed on I-sections and brick paver blocks, revealing that the 1:4 mix ratio exhibited the highest average compressive strength for both materials. The findings indicated that including plastic waste positively impacted the compressive strength of the I-sections and brick paver blocks. Additionally, the quality grading of these materials was evaluated using an ultrasonic pulse velocity test. The ultrasonic pulse velocity test results demonstrated a high-quality grading for the I-sections and brick paver blocks. Scanning electron microscopy (SEM) tests assessed the microstructural behavior and performance. The results of this study demonstrate that incorporating plastic waste in combination with M-sand can effectively improve the mechanical characteristics of composite materials, rendering them viable for use in construction-related purposes.
]]>CivilEng doi: 10.3390/civileng4040057
Authors: Mohamed A. Hammad Yahia Mohamedzein Mohamed Al-Aghbari
Saline soils belong to the category of problematic soils with high compressibility and weak shear strength when exposed to water. Water dissolves the salts in soils which are the primary cementing agents. Therefore, stabilization methods that provide sustainable cementing substances are employed in this study using deep soil mixing techniques to enhance the properties of saline soil. In this regard, a laboratory-scaled deep soil mixing procedure was developed to treat the soil in a way similar to the field methods. A binder, consisting of marble powder and cement, was employed to treat the soil. This study aimed to select the most efficient binder mix design in terms of optimum marble powder/cement ratio and optimum water/binder ratio. Unconfined compressive strength, durability, density measurements and ultrasonic velocity pulse tests were conducted on the treated soil. To determine the treatment efficacy, microstructure analysis of the treated samples was conducted. The 80C20MP and 70C30MP samples exhibit a dense soil structure with minimal voids, and their microstructure is denser than the other treated specimens. Additionally, the EDX analysis shows increased calcium percentages with up to 30% MP replacement, aligning well with the microstructure analysis and the UCS values. The results indicate that the economical and eco-friendly binder mix consisted of (70% to 80%) cement and (20% to 30%) marble powder with water/binder ratio in the range of 1.1 to 1.3. This mix contributed greatly to the improvement in soil strength and integrated columns.
]]>CivilEng doi: 10.3390/civileng4030056
Authors: Mu’tasim Abdel-Jaber Nasim Shatarat Hasan Katkhuda Hebah Al-zu’bi Rawand Al-Nsour Rouzan Alhnifat Ahmad Al-Qaisia
The innovation inherent to employing expanded polystyrene (EPS) beads lies in its transformative impact on traditional concrete practices. Through the incorporation of EPS beads in concrete mixtures, a novel approach emerges that significantly alters the material’s characteristics, and opens up new avenues for construction and design. Studying the shear behavior of RC beams made with EPS beads is essential for advancing knowledge, improving design practices, ensuring structural integrity, and promoting the effective and responsible use of innovative materials in construction. This research experimentally investigated the effect of using EPS beads and pozzolana aggregate (PA) on the shear behavior of the RC beams. A total of 27 simply supported rectangular beams were cast, using three novel distinct mix designs, and were subjected to two-point load testing until failure. These three mixes were categorized as follows: a control mix, a mix with only EPS, and a mix with EPS, along with an additive. The ultimate failure load was experimentally recorded for all specimens, and the influence of the temperature (300 °C and 600 °C) on the RC beams made with EPS was examined. The findings revealed a reduction in the concrete compressive strength and density in the beams containing EPS and EPS with superplasticizers of (21.7%, 24.9%) and (11.3%, 16.2%), respectively. Additionally, EPS played a significant role in diminishing the ultimate shear capacity of the beams, compared to the control beams, by about 19.4%. However, the addition of a superplasticizer along with the EPS helped to maintain the beam capacity, to some extent. Conversely, the beams exposed to a temperature of 300 °C exhibited an almost similar capacity to that of the control beams without heating. Nevertheless, at 600 °C, the beams displayed a noticeable decrease in the ultimate load capacity, compared to the unheated control beams.
]]>CivilEng doi: 10.3390/civileng4030055
Authors: Sama Tajasosi Ashkan Saradar Jalil Barandoust Mohammad Mohtasham Moein Reza Zeinali Moses Karakouzian
In developing countries, ultra-high-performance concrete (UHPC) has not garnered sufficient attention, and its potential industrial applications remain largely unexplored and underdeveloped. The purpose of this paper is to assess the risk associated with integrating UHPC technology into the construction industry, focusing on economic, technical, and environmental facets, as highlighted by global research endeavors in this domain. In this study, a risk model is validated by analyzing diverse UHPC mix proportions from various studies and assessing the associated risk indices concerning constituent materials. The findings demonstrate that incorporating UHPC as a more robust alternative to earlier generations is plausible when considering multiple perspectives within the concrete industry. The preeminence of compressive strength and the significance of service life as a pivotal cost factor during the maintenance period, coupled with comprehensive risk indices, underscore the excellence of UHPC. Comparing UHPC with high-performance concrete (HPC) and normal concrete (NC), it becomes evident that UHPC exerts a notably lower adverse impact on the ecosystem. Additionally, UHPC proves to be a more economically viable option, warranting the replacement of existing technologies.
]]>CivilEng doi: 10.3390/civileng4030054
Authors: Anton Chepurnenko Vasilina Turina Vladimir Akopyan
Concrete-filled steel tubular (CFST) columns are one of the most effective reinforced concrete structures, and improving their calculation is a critical task. The purpose of this study was to develop a simplified method for calculating slender CFST columns, taking into account the effect of lateral compression. The idea of the method is to use the equation of a reinforced concrete column’s longitudinal bending, without taking into account the effect of lateral compression. To take into account the lateral effects, the cross-sectional stiffnesses are corrected based on the analysis of the stress–strain state in the cross-sectional plane using the finite element method. The developed method was implemented by the authors in the MATLAB environment. The approbation of the proposed method was carried out on experimental data for centrally compressed columns of a circular cross-section, as well as eccentrically compressed columns of a circular and square cross-section, presented in two papers. For the centrally compressed columns, we conducted a study on the influence of initial imperfections in the form of eccentricities and initial curvatures on the value of the ultimate load. For the eccentrically compressed columns of the circular and square cross-section, the area of their effective operation was determined.
]]>CivilEng doi: 10.3390/civileng4030053
Authors: Hamza Imran Duaa Al-Jeznawi Musab Aied Qissab Al-Janabi Luís Filipe Almeida Bernardo
Mechanically stabilized earth (MSE) walls are recognized for their cost-effectiveness and superior performance as earth-retaining structures. The integration of internally reinforced walls has transformed soil preservation practices, garnering significant attention from the global technical community. The construction method of MSE walls has recently gained widespread popularity, likely due to its cost efficiency and simplicity compared to traditional externally reinforced walls. This paper provides a comprehensive review of MSE walls, including their historical development, aesthetics, benefits, drawbacks, factors influencing lateral displacements and stress responses, and the concept of the MSE wall system. Key approaches for analyzing seismic soil–structure interaction (SSI) issues are emphasized, investigating the dynamic interaction between the structure and soil through various research methodologies. This study incorporates multiple publications, offering an in-depth review of the current state of dynamic SSI studies considering surrounding structures. The findings emphasize the significant sensitivity of the dynamic behavior of mechanically stabilized earth (MSE) walls to soil–structure interaction, highlighting the necessity for continuous research in this area. The paper identifies research gaps and proposes future directions to enhance MSE wall design and application, facilitating further advancements in earth-retaining structures.
]]>CivilEng doi: 10.3390/civileng4030052
Authors: Shayan Shamohammadi Ahmad Reza Ghasemi Kaveh Ostad-Ali-Askari Saeedeh Izadi
This study aims to correct and assess the SCS-CN model. In this research, the 3RM model (written by Shamohammadi) has been modified in such a way that the maximum primary retention (I), maximum secondary retention (Fmax), and basin potential retention (Smax) can be calculated using precipitation (Pa). The purpose of this study is to evaluate the total retention model (St=f(Fmax,Smax,pa)) and the runoff model (Q=f(St,pa)) using the mountain basins of Iran, including Emameh, Kasilian, Navrood, Darjazin, Kardeh, Khanmirza, and Mashin. The results showed that the primary retention, maximum secondary retention, and retention capacity are, respectively, 2.3, 30.4, and 32.7 mm in Imamah, 2.5, 48.6, and 51.1 mm in Kasilian, 2.4, 26.7, and 29.1 mm in Navrood, 3.2, 21.5, and 24.7 mm in Darjazin, 1.7, 15.0, and 16.7 mm in Kardeh, 2.5, 33.2, and 38.1 mm in Khanmirza, and 4.9, 44.5, and 50.6 mm in Mashine. Additionally, the λ (ratio of primary retention to potential retention) values for all basins are less than 0.2 (suggested by SCS) and vary between 0.05 in Kasilian and 0.1 in the Darjazin, Kardeh, and Mashine basins. The results of fitting the model to the rainfall-runoff data showed that the evaluation indices, including the coefficient of determination (R2), Nash–Sutcliffe (NS), and root mean square error (RMSE), for predicting the runoff in the basins varied between 0.78 to 0.96, 0.78 to 0.961, and 0.86 to 2.28, respectively. According to the obtained results, it can be concluded that the model has an acceptable ability to predict runoff for all the studied basins.
]]>CivilEng doi: 10.3390/civileng4030051
Authors: Ali Javadi Kaveh Ostad-Ali-Askari
The main aim of this paper was to analyze the sensitivity of the five infiltration equations (Kostiakov, Kostiakov–Lewis, Philip, Horton and SCS) and their coefficients to various ponding depths and initial soil moisture under different irrigation managements. The treatments included three qualities of water (electrical conductivity = 6, 3 and 0.6 dS/m), two managements of irrigation (intermittent irrigation and daily irrigation) and three irrigation periods (100, 45 and 8 days). The HYDRUS-1D model was calibrated to simulate infiltration in various initial soil moistures and ponding depths. Evaluating the performance of infiltration equations showed that the Horton and Kostiakov–Lewis had better accuracy and Kostiakov and SCS had less accuracy than the other equations. The empirical coefficients of SCS and Kostiakov had the most and least sensitivities, respectively. Furthermore, Horton was the most sensitive equation, while SCS was the least sensitive one. The output parameters under daily management were the most sensitive to variations in infiltration coefficients, especially when the salinity and sodium contents of water and soil were higher. The results also showed that the effect of the initial soil moisture on the infiltration coefficient in high permeable soil (arising from daily management) was greater; but in low permeable soil (arising from intermittent management), the ponding depth was more effective. It is concluded that the infiltration equations (specifically the SCS equation) and their coefficients (specifically coefficient c) should be calibrated relative to the initial soil moisture, ponding depth, soil solution and water irrigation quality. Particularly in areas with high permeable soil (in the daily management), the calibration of the infiltration equation should be conducted with the initial soil moisture. In these areas, the irrigation period should be controlled. In areas with low permeable soil (in intermittent management), calibration should be carried out relative to the ponding depth. In these areas, the inflow rate should be controlled.
]]>CivilEng doi: 10.3390/civileng4030050
Authors: Shiblu Sarker
A floodplain is an area of low-lying land adjacent to a river, stream, or other water body that is regularly inundated by water during periods of high flow. Floodplains typically have relatively flat terrain and are composed of sediments deposited by the river over time. Floodplain flow refers to the movement of water across the surface of the floodplain during periods of high flow. This flow can occur as a result of water spilling over the river banks or seeping into the ground and then re-emerging on the surface of the floodplain. Bankfull discharge is the flow of water that just fills the channel of a river or stream to the top of its banks. It is the point at which the river or stream is at its maximum capacity without overflowing onto the floodplain. Bankfull discharge is often used as a reference point for assessing flood risk and planning floodplain management strategies. To examine the bank-to-bank hydro-morphodynamics of a river, it is necessary to comprehend the flow distribution throughout the main stream and floodplain. Along with river hydraulics, bankfull discharge is a crucial parameter for estimating river bank erosion. For evaluating the distribution and generation of river flow over the floodplain and main stream, a variety of modeling tools and approaches are available. This study investigates methods for separating floodplain flow and bankfull discharge from observed discharge data using the one-dimensional momentum equation. A two-dimensional modeling tool (MIKE 21C) was also employed to investigate the usefulness of the proposed method in a region with an enormous floodplain.
]]>CivilEng doi: 10.3390/civileng4030049
Authors: Mostafiz Emtiaz Md Nafis Imtiyaz Mishuk Majumder Ipshit Ibne Idris Roni Mazumder Md Mafuzur Rahaman
Due to periodic variations in temperature and heavy traffic loading, hot-mix asphalt (HMA) pavements undergo considerable distress during their service life. The rheological properties of asphalt binder, when subjected to complex physical and chemical processes, make it stiff and sometimes brittle, which ultimately plays a huge part in pavement deterioration. This phenomenon is commonly known as asphalt aging. Incorporating polymer modifiers with virgin asphalt can work as an effective means to change the binder properties and alleviate the issues related to asphalt aging. Different types of polymers, including elastomers, plastomers, and reactive polymers, can mixed in different combinations with the virgin asphalt to create polymer-modified binders (PMBs). In general, polymers are typically added to the virgin asphalt binder in PMB manufacturing at weight percentages ranging from 3% to 7%. Previous research suggests that many polymer-modified binders (PMBs) show great resiliency and perform extremely well during field and laboratory testing, although the complex nature of asphalt itself makes it significantly difficult to understand the relationship and compatibility of the asphalt–polymer system. This paper aims to develop a comprehensive literature review on the chemical aspects, microscopic structure, and compatibility of polymers with virgin asphalt. It was found that swelling, storage stability, blend morphology, and the polymer mixing technique play a great role in the compatibility of asphalt–polymer systems. Thermoplastic elastomers (e.g., styrene–butadiene–styrene) and plastomers (e.g., ethylene–vinyl acetate) are the most used polymer modifiers for asphalt binders. The compatibility of the polymer–asphalt system can be improved by sulfur vulcanization, antioxidants, hydrophobic clay minerals, functionalization, and reactive polymers, among other techniques.
]]>CivilEng doi: 10.3390/civileng4030048
Authors: Prashidha Khatiwada Yiwei Hu Nelson Lam Scott J. Menegon
This paper aims to guide structural engineers on how to apply the rapid nonlinear time history analysis (RNLTHA) procedure effectively to predict seismic demand, taking into account ductility and overstrength, and effects of dynamic phenomena including cyclic degradation of strength and stiffness in structures, in a direct and expedient manner. The shortcoming of the conventional force-based approach of design involving the use of a force reduction factor to account for nonlinear effects is well recognised. Nonlinear static (pushover) analysis and dynamic nonlinear time history analysis (NLTHA) are offered as alternative methods of analysis by major codes of practices to achieve better optimisation in the use of materials. NLTHA has advantages over pushover analysis in being more direct and capable of capturing cyclic response behaviour. Despite the merits of NLTHA, its adoption in the industry has been limited, mainly because of the complexity and the higher analysis cost involved. RNLTHA proposed in this article uses a macroscopic model of the building to fulfil the purpose of NLTHA, whilst saving computational time and achieving a good degree of accuracy, as verified by comparison with results generated from SeismoStruct.
]]>CivilEng doi: 10.3390/civileng4030047
Authors: Maria C. Naoum Constantin E. Chalioris Chris G. Karayannis Athanasios I. Karabinis Anaxagoras Elenas
Fiber Reinforced Concrete (FRC) has shown significant promise in enhancing the safety and reliability of civil infrastructures. Structural Health Monitoring (SHM) has recently become essential due to the increasing demand for the safety and sustainability of civil infrastructures. Thus, SHM provides critical benefits for future research to develop more advanced monitoring systems that effectively detect and diagnose the damage in FRC structures. This study investigates the potential of an Electro-Mechanical Impedance (EMI) based SHM system for detecting cracks in FRC prisms subjected to four-point repeated loading. For the needs of this research, an experimental investigation of three FRC specimens with the dimensions 150 × 150 × 450 (mm) were subjected to three different loading levels where no visual cracks formed on their surface. Next, prisms were subjected to reloading until they depleted their load-carrying capacity, resulting in pure bending fracture at the mid-span. A network of nine cement paste coated Piezoelectric lead Zirconate Titanate (PZT) transducers have been epoxy bonded to the surface of the FRC prisms, and their frequency signal measurements were utilized for quantitative damage assessment. The observed changes in the frequency response of each PZT sensor are evaluated as solid indications of potential damage presence, and the increasing trend connotes the severity of the damage. The well-known conventional static metric of the Root Mean Square Deviation (RMSD) was successfully used to quantify and evaluate the cracking in FRC specimens while improving the efficiency and accuracy of damage detection. Similarly, the dynamic metric of a new statistical index called “moving Root Mean Square Deviation” (mRMSD) was satisfactorily used and compared to achieve and enhance accuracy in the damage evaluation process.
]]>CivilEng doi: 10.3390/civileng4030046
Authors: Yiwei Hu Nelson Lam Prashidha Khatiwada Hing-Ho Tsang Scott Menegon
This paper is aimed at serving the needs of structural engineering designers of an important structure (or a group of structures located on the same site) who is seeking guidance on how to obtain accelerograms and/or derive response spectra that accurately represent the site subsoil conditions as informed by the borelogs. The presented site-specific seismic action model may be used to replace the default seismic action model stipulated for the designated site class. Presented in this article is a procedure for generating soil surface motions in an earthquake, and their associated site-specific response spectra, taking into account details of the soil layers. Dynamic site response analyses are involved. The conditional mean spectrum methodology is employed for selecting and scaling accelerograms for obtaining input motion on bedrock. The selection depends on the natural period of both the site and the structure. Multiple borelogs taken from within the same site are analysed to identify the critical soil column models without having to conduct site response analysis on every borelog. The technique for simplifying the soil layers utilising the shear strain profile is introduced to further cut down on the time of analyses. The procedures described in this article have been written into a web-based program that is freely accessible to engineering practitioners.
]]>CivilEng doi: 10.3390/civileng4030045
Authors: Luís Jacques de Sousa Maria Lurdes Simões João Poças Martins Luís Sanhudo Jorge Moreira da Costa
During the tender phase of public construction projects in Portugal, documents that describe the project are mandatorily submitted to open data repositories. However, in their current state, most of these repositories do not allow for benchmarking analysis due to a lack of data treatment and cohesion. This paper seeks to diagnose the main trends during the public construction project’s tender phase by performing a descriptive statistical analysis on the Portuguese Public Procurement Database (PPPData), a database that compiles 5172 public procurement contracts in Portugal from 2015 to 2022, to respond to the research gap in construction procurement benchmarking. The results of this statistical analysis draw out the main trends, uncover which tender variables can influence budget compliance, and diagnose Portugal’s public procurement in terms of its geographical, temporal, financial, and performance dispersion. This paper concludes that the award criteria are not correlated with final project performance and that multifactor assessment criteria do not necessarily lead to better performance. High-value projects awarded solely with the price award criterion tend to perform worse than those awarded with the multifactor assessment. The study also identified frequent errors and omissions in construction reporting; thus, there is a need for error mitigation tools.
]]>CivilEng doi: 10.3390/civileng4030044
Authors: Khalil Jebara Akanshu Sharma Joško Ožbolt
Current formulas to assess the shear capacity of headed steel stud anchors and post-installed (PI) anchors in case of pryout failure (sometimes known as pull-rear failure) have been derived either based on the indirect-tension resistance model or are fully empirical based on push-out test results. In both cases, the predicted pryout capacity is clearly conservative and underestimates the true pryout capacity of anchorages, especially for stiff anchors with low embedment-to-diameter ratios (hef/d < 4.5). This paper proposes an empirical and a semi-empirical formula to predict the concrete pryout capacity of headed steel studs and PI anchors. They were derived based on an improved indirect-tension model which accounts for the stud diameter and the stud spacing in a group of anchors. Furthermore, a database of 214 monotonic shear tests from the literature, including own tests (push-off and horizontally shear tests), is reevaluated and compared to the provisions of EN1992-4. The scope of this assessment proposal includes single and group of headed steel studs and PI anchors attached to a stiff steel plate as well as shear connectors in composite structures without metal deck embedded in normal-weight concrete.
]]>CivilEng doi: 10.3390/civileng4030043
Authors: Mohammadhossein Mamaghani Eric M. Lui
This paper presents the use of continuous wavelet transform (CWT) to capture the frequency contents, spectra of dominant frequencies and associated time durations of real earthquakes for generating artificial excitations to perform endurance time analysis (ETA) of structures. Applying CWT to three sets of forty earthquakes, the 90 percentile frequencies that span the ranges 0.08–18.41 Hz, 0.61–12.73 Hz, and 0.56–15.53 Hz; with associated time durations of 20, 15 and 16 s, respectively, for these earthquake sets are extracted. Artificial excitations that contain these ground motion characteristics are generated, progressively scaled up and applied to the target structure until failure. The scaling used is a block-shaped envelope that increases in size by a factor of 3/2 over time. Nonlinear seismic analyses of a steel frame and a concrete bridge bent using these artificial excitations have shown that the method not only successfully predicts the base shear–roof displacement responses of these structures, it also correctly identifies behavior such as weak story, concrete spalling, and core cracking. When compared with the increment dynamic analysis and time history analysis using multiple earthquakes, the proposed method is capable of producing comparable results with a significant reduction in computational time and a much smaller output file size.
]]>CivilEng doi: 10.3390/civileng4030042
Authors: Anton Chepurnenko Vasilina Turina
For massive monolithic foundation slabs, the problem of early cracking due to the intense heat release of concrete during the hardening process is relevant. The purpose of this article is to develop a simplified method for determining thermal stresses during the construction of massive monolithic foundation slabs. The proposed technique is based on the hypothesis of parabolic temperature distribution over the thickness of the structure at each moment of time. In addition to the parabolic distribution, the half-wave cosine distribution is also used. A hypothesis is also introduced about the same conditions of heat exchange with the environment on the lower and upper surfaces of the foundation. As a result, formulas are obtained that establish a direct relationship between thermal stresses and the temperature difference between the center and the surface. The solution to the test problem for the foundation slab is presented and compared with an alternative technique that does not use the hypothesis about the character of the temperature distribution over the thickness. Also, the inverse problem of determining the allowable temperature drop between the center and the surface of the structure is solved, at which the stresses on the upper surface at each moment of time will not exceed the tensile strength of concrete.
]]>CivilEng doi: 10.3390/civileng4030041
Authors: Tatiana P. Moschovou Dimitrios Kapetanakis
The current paper presents the results of a study that analyzed and evaluated the efficiency of the largest container ports in the wider area of the Mediterranean Basin. The research question that this paper seeks to respond to is how the resources (inputs) of a container port reflect its level of activity and efficiency. In particular, what is the relationship between ports’ infrastructures, equipment and their productivity and the ports’ ability to attract economic activities as well as the extent of their effect on a port’s efficiency? The methodology uses the data envelopment analysis (DEA) output-oriented model following a cross-sectional approach. The research conducts two modeling approaches, the CCR and the BCC model. The analysis goes deeper and compares port efficiency estimates in relation to medium-sized and large ports’ classification and their total market share. The main findings indicated an average efficiency of 0.88 and 0.89 assuming constant and variable returns of scale, respectively, implying that the ports can increase their output levels up to approximately 1.2 times without any change in their inputs.
]]>CivilEng doi: 10.3390/civileng4030040
Authors: Nastaran Cheshmehkaboodi Lotfi Guizani Noureddine Ghlamallah
Seismic isolation is a powerful tool for mitigating seismic risk and improving structural performance. However, some parameters, such as earthquake inputs and soil characteristics, influence the technology’s performance. This research aims to investigate the effects of soil–structure interaction (SSI) with regard to different moderate earthquakes associated with different distances of the source to the site, frequency content, and different soil characteristics on the seismic response of the isolated bridges. Near-fault (NF) and far-field (FF) records are applied to the conventional and isolated bridge with and without considering the underlying soil. For this reason, using the direct and simplified methods, three soil properties representing rock, dense, and stiff soils are modeled in Abaqus software. Nonlinear time history analysis (NLTHA) is carried out, and structural responses of both approaches in terms of maximum deck acceleration, base shear, and displacement of the deck and the isolation system are studied. Results demonstrate that the difference between the two approaches is significant. Using the simplified method is a rather simple approach that roughly captures the important features of the record characteristics and SSI. Furthermore, careful attention should be paid to the base shear responses and the isolator displacement demands, as they are significantly amplified in softer soils. In addition, the peak ground acceleration to peak ground velocity ratio (PGA/PGV) plays a decisive role in all dynamic responses. Records with a lower PGA/PGV ratio cause higher dynamic responses in terms of displacement and acceleration/force, regardless of the distance of the ruptured fault, while NF records show higher dynamic responses compared to FF records.
]]>CivilEng doi: 10.3390/civileng4020039
Authors: Yohannes L. Alemu Bedilu Habte Tom Lahmer Girum Urgessa
Simplicity and optimality are commonly associated with the particle swarm optimization (PSO) algorithm. As a result, numerous variants and hybrids of PSO have been developed and implemented to address structural optimization problems. The undeniable importance of the initialization technique in determining the overall performance of a given optimization algorithm cannot be overstated. Optimization algorithms, such as PSO, typically rely on a random, uniformly distributed initialization. Through multiple iterations and updates, these algorithms aim to achieve optimal results. The underlying assumption behind such an initialization approach is that a fair or reasonable arrangement of particles is best accomplished through randomization, and thus the entire optimization process is iterated based on this assumption. However, this initialization technique raises concerns regarding the attainment of optimality and convergence, leaving room for further examination. In this paper, we challenge this assumption by introducing a priority concept. The key idea is that particles should not be initialized randomly since randomness alone does not guarantee a reasonable allocation of design variable values in iterative optimization. This can lead to misguided velocity updates and ultimately, a time-consuming pursuit of optimality. To address this issue, we formulate priority criteria (PC) and propose an enhanced PSO variant called Priority Criteria PSO (PCPSO). The PC can be incorporated into any PSO variant or hybrid without impacting the parameter settings, constraints, and penalty approaches of the respective algorithms. A case study involving 2D reinforced concrete frames was conducted to compare the performance of the ordinary PSO algorithm with the PCPSO. The results clearly demonstrate that the introduction of the PC leads to a significant cost reduction when compared to PSO with an inertia damping factor. Additionally, the PCPSO algorithm exhibits accelerated convergence. Furthermore, to alleviate the computational burden associated with structural analysis at each iteration, a reanalysis approach called Combined Approximations (CA) is mathematically formulated and implemented.
]]>CivilEng doi: 10.3390/civileng4020038
Authors: Pedro Cantor António Renato Bicelli Ellon Bernardes de Assis Mário Rui Arruda Fernando Branco
This work presents a state-of-the-art review of existing fireproof construction guidelines for dwellings against wildfires. The most important wildfire-proof construction guidelines and codes for dwellings are presented, and these are later associated with existing fire engineering chapters associated with building codes. It was concluded that the variability in this subject is very high, and the approach to classifying the thermal effects in construction still lags behind scientific consensus. Moreover, the constructive requirements depend severally on the country’s building code when assessing the fireproof requirements for wildfire. Moreover, the thermal actions of wildfires in dwellings are presented and compared with classical ISO-834 standard fire curves, in which the maximum equivalent fire exposure time can range from 2 to 4 h depending on the country’s code. The key contributions of this work consist of (i) thoroughly disseminating codes and guidelines to promote scientific discussion in order to advance the wildfire fireproof standards dedicated to WUI; (ii) emphasizing the void in current codes in order to promote conversation between future researchers.
]]>CivilEng doi: 10.3390/civileng4020037
Authors: Muhammad Waseem Syed Mutahir Ullah Ghazi Nameer Ahmed Muhammad Ayaan Megersa Kebede Leta
Pakistan is currently facing physical and economic water scarcity issues, which have been further complicated by the rapid increase in its population and climate change. In affected areas, many methods are being used to tackle this problem, among which rainwater harvesting (RWH) provides the best alternative source of domestic water supply. In rainwater harvesting, a mechanism is designed to effectively collect surface runoff during rainfall events from residential rooftops. It has also been found that rainwater has great potential as a source of water supply in residential areas of major cities, such as Lahore, which is the focus of our study. This research paper examines rainwater harvesting as a sustainable solution to address the challenges of drinking water scarcity and urban flooding. The study discusses the benefits of rainwater harvesting, including reducing reliance on municipal water sources, improving water quality, and mitigating the impact of urban flooding. Additionally, the paper explores the use of filtered water points in conjunction with rainwater harvesting systems to provide clean drinking water to communities. The research draws on case studies from various regions to illustrate the effectiveness of rainwater harvesting as a sustainable solution to water scarcity and urban flooding. Ultimately, the study concludes that rainwater harvesting, when coupled with filtered water points, can offer an effective and sustainable solution to address drinking water scarcity and urban flooding.
]]>CivilEng doi: 10.3390/civileng4020036
Authors: Grigorios E. Manoukas Chris G. Karayannis
Structural pounding between adjoining multistory buildings with different total heights and different story levels has been repeatedly identified as a frequent cause of severe damage during seismic excitations. This phenomenon is very intense when upper floor slabs of short buildings hit the columns of taller and more flexible structures within their deformable length. On the other hand, it is well accepted that infill masonry panels strongly affect the seismic response and overall behavior of multistory reinforced concrete (RC) frames and especially in the common case of an open first story (pilotis). Thereupon, the interaction between a multistory frame with an open first floor and shorter and stiffer adjacent buildings was studied and the influence of the open first story on pounding investigated with inelastic dynamic step-by-step analyses. The results of the pounding cases of an 8-story RC frame with a single story and 4-story buildings were examined. Three cases of short structures were considered as follows: a frame structure, a stiff structure and a very stiff non-self-vibrating one. All studied interaction cases included type A (floor-to-floor) pounding cases and type B (floor-to-column) pounding cases. This study focused on the influence of an open first story (pilotis) on the pounding phenomenon. Therefore, all examined two-building poundings were studied considering two cases: the first case involving a fully infilled 8-story frame and second case involving an infilled 8-story structure with an open first story (pilotis). Moreover, as expected due to the asymmetry of the examined two-structured pounding pairs, the directions (plus and minus) of the seismic excitation proved to be important for the evaluation of the developing capacity demands. In the present study for the first time, it is stressed that pounding cases between structures with different geometries (asymmetric) have to be examined in both directions (plus and minus) of each seismic excitation. From the results, it can be deduced that the developing shear forces on the columns that suffer a hit in the case of type B pounding exceed the shear strength of the column even if detailing for critical regions according to Eurocode 8 is applied. Further, it is inferred that pilotis configuration increases the developing pounding forces and consequently increases the capacity demands mainly in terms of the ductility of the column that suffers the hit.
]]>CivilEng doi: 10.3390/civileng4020035
Authors: Amin Akhnoukh Ahmed Fady Farid Ahmed M. M. Hasan Youssef F. Rashed
Magneto-rheological dampers (MR-Dampers) are increasingly being used in construction applications to reduce the dynamic response of structures to seismic activities or severe wind loading. Sensors attached to the structure will signal the computer to supply the dampers with an electric charge that transfers the MR fluid to a near-solid material with different physical and mechanical properties (viscoelastic behavior). Control algorithms govern the fluid to near-solid conversion, which controls the behavior of the damper and the performance of the structure under the seismic or wind loading event. The successful optimization of control parameters minimizes the overall structural response to dynamic forces. The main objective of this research is to change the output behavior of specific floors within a building subjected to seismic excitation by optimizing the MR-Damper control parameters to impact the behavior of a specific floor or number of floors within the building. The adjustment of control parameters to attain this objective was validated in multiple case studies throughout this research. The successful implementation of the research outcome will result in optimized MR-damper design to meet the performance-based criteria of building projects.
]]>CivilEng doi: 10.3390/civileng4020034
Authors: Mário R. T. Arruda Pedro Cantor Renato Bicelli
This paper presents a numerical study on the thermal effect of the insulation of lightweight concrete in hybrid GFRP-concrete structures. In these hybrid structures, the GFRP profiles are totally covered by normal and lightweight concrete and subjected to thermal loads. The problem with GFRP structures is their weak thermal resistance, even at moderately high temperatures. To promote some thermal insulation, it is recommended to cover the GFRP profile with concrete, but this increases its weight. Therefore, lightweight concrete may be a good solution due to its insulation capabilities. For this study, the thermal loads used in the numerical campaign are based on a nominal fire-curved ISO-834, and the temperature is measured at several points. Using these temperatures, it is possible to conclude that the effect of lightweight concrete may provide structural benefits when compared with classical standard structural concrete for covering GFRP profiles using different cover values (from 5.0 cm to 2.5 cm). For this work, commercial finite element software was used for the thermal nonlinear analysis. It was possible to conclude that with lightweight concrete, it is likely to have half of the cover and still maintain the same level of insulation as regular concrete.
]]>CivilEng doi: 10.3390/civileng4020033
Authors: Chengcheng Tao Shanyue Guan
To address the rapidly growing demands of traffic congestion, more highway bridges have been constructed, especially curved bridges. With more curved bridges designed and constructed, people have conducted a comprehensive analysis of the structural performance. Due to the nature of the structural complexity of curved bridges, dynamic responses of the curve bridges vary dramatically from the standard linear bridges. Although some work has been conducted to investigate the curved bridge dynamic analysis under seismic inputs, the framework for analyzing the curved bridges’ vulnerability under various angles of inputs is still lacking. In this paper, we conducted a series of curved bridge seismic analyses based on different inputs and conducted a parametric study of the bridge performance using finite element models. We conducted time history analyses by applying seismic inputs to investigate the bridge dynamic responses based on different angle inputs and other different structural parameters. We developed an approach identifying the most vulnerable direction of the seismic inputs and the strongest dynamic responses for curved bridges based on time series analysis. This approach was validated with the dynamic analysis of a simplified bridge model. The method developed in this paper will help improve the curved bridge design code and further provide suggestions about mitigating seismic response for device design.
]]>CivilEng doi: 10.3390/civileng4020032
Authors: Nasreen B. Pathan Logan Couch Fariborz M. Tehrani Ali Naghshineh Oliver Fischer
Existing literature suggests that substituting mineral aggregates with tire-derived aggregate (TDA) in concrete increases the ductility and toughness of the concrete at the cost of lowering its strength and stiffness. Hence, TDA concrete has applications in dynamic systems, such as lateral resisting frames sustaining seismic loads. This study investigated the application of TDA concrete in buckling-restrained braced frames (BRBFs). Buckling-restrained brace (BRB) specimens included steel plates encased with concrete mixtures containing TDA coarse aggregates compared to conventional concrete. Testing involved shake-table testing of a single-span, one-story, steel-braced frame with single-leg conventional or TDA concrete BRBs under harmonic, periodic, impulse, and ground motion loadings. Results included time-history responses and backbone curves of the BRBF specimens. Analytical interpretation of results included determining effective mass, stiffness, damping ratio, toughness, and ductility of BRBFs for TDA versus conventional concrete.
]]>CivilEng doi: 10.3390/civileng4020031
Authors: Koorosh Gharehbaghi Kong Fah Tee Kerry McManus
While megaprojects can be defined as highly complex, time-consuming, and cost-intensive endeavors, for rail infrastructures they are even more problematic. As a starting point, for rail megaprojects, their scope may, at times, alter due to some risks and uncertainties. As many such projects exceed many years in development, their scope and formation will not be a linear trajectory. It is, therefore, the aim of this paper to evaluate the difficulties in determining the scope of rail megaprojects. This paper first introduces the theoretical framework via adaptive decision-making and policy setting when dealing with mega rail projects. Through sustainable development, carefully applied research is undertaken to highlight some of the key shortfalls of current practices when dealing with mega rail projects. This includes categorizing sustainability into four dimensions: social, economic, environmental, and engineering for rail infrastructure. To address the existing gap in the literature, including the appropriate alignment of policy planning and design, this paper will carefully review the complex science of rail megaprojects. This can be seen as a conceptual framework, which combines complex theory and practice to develop a theoretical perspective to initiate, plan, execute, and commission mega rail projects. Particularly with an international focus, this paper will review global development, targeting rail infrastructures. For rail megaprojects, strategically integrated objectives are traditionally key functions within the regional land transport network along with the national network and are necessary to (i) improve connectivity, both nationally and inter-regionally for people, communities, regions, and industry via effectively linking the existing broad-based transport network; (ii) enhance logistical systems and trade; (iii) provide a consistent framework for continuous sustainable development; and (iv) provide a consistent framework for long-term economic and social benefits.
]]>CivilEng doi: 10.3390/civileng4020030
Authors: Fawzi Latosh Abobakr Al-Sakkaf Ashutosh Bagchi
Unlike steel reinforcements in concrete, Fiber Reinforced Polymer (FRP) materials are light and free from corrosion. Therefore, FRP materials are increasingly being used in structural engineering as a replacement for steel reinforcements. While the use of FRP bars as longitudinal reinforcements in concrete deep beams has been studied somewhat widely, their use and effectiveness as web reinforcements are not well studied. In this study, the effect of the FRP web reinforcements on the behaviour and strength of FRP-reinforced concrete deep beams were investigated in an experimental study. Four glass fiber-reinforced concrete (RC) simply supported deep beam specimens were tested under a concentrated load with different shear span-to-depth ratios and web reinforcement ratios. The behaviour of the deep beams was described in terms of load–deflection behaviour, crack developments, strain in FRP reinforcements, and failure modes. The experimental investigation emphasized the significance of web reinforcements in determining the reinforced concrete deep beam behaviour, such as mid-span deflection, crack breadth, failure modes, and ultimate strengths. Furthermore, to predict the behavior of deep beams, numerical Finite Element models using Abaqus software were created. The present test results were compared to those predicted using the Finite Element models. This investigation shows that web reinforcement is quite important for FRP-RC deep beams to achieve a robust behaviour by enhancing its capacity and deformability.
]]>CivilEng doi: 10.3390/civileng4020029
Authors: Chamath Ravindu Senevirathna Chaminda S. Bandara Sudath C. Siriwardane
Damage assessment of corroded steel members due to severe exposure conditions, has been a vital component for determining the strengthening requirements of existing deteriorated structures, to overcome possible devastating failures. This article mainly focuses on steel angle members, which are mostly used as axially loaded members in different types of applications. In this study, the strategy of thickness reduction at corroded locations was demonstrated as a simple, convenient, and accurate method to represent the corrosion-equivalent properties of steel angles under axial compression. Further, the viability of the thickness reduction approach was evaluated in code-based and numerical approaches. Four standards, BS 5950-1:2000, BS EN 1993-1-1:2005, ASCE 10-15 and ANSI/AISC 360-16 were investigated to identify their applicability to obtain the residual compression capacities of corroded members. The capacity estimations of codes were compared with experimental data to demonstrate that the estimations of codes are not accurate when the level of corrosion is high. Finally, 39 corroded steel angle members of 10 different corrosion patterns were numerically modeled and analyzed to demonstrate the impact of different corrosion patterns on the compression capacity.
]]>CivilEng doi: 10.3390/civileng4020028
Authors: Ayman El-Zohairy Suzan Mustafa Hesham Shaaban Hani Salim Abbas A. Allawi
Strengthening of composite beams is highly needed to upgrade the capacities of existing beams. The strengthening methods can be classified as active or passive techniques. Therefore, the main purpose of this study is to provide detailed FE simulations for strengthened and unstrengthened steel–concrete composite beams at the sagging and hogging moment regions with and without profiled steel sheeting. The developed models were verified against experimental results from the literature. The verified models were used to present comparisons between the effect of using external post-tensioning and CFRP laminates as strengthening techniques. Applying external post-tensioning at the sagging moment regions is more effective because of the exhibited larger eccentricity. In the form of an initial camber and compressive stresses in the bottom flange prior to loading, this reasonable eccentricity induces reverse loading on the reinforced beams, reducing the net tensile stress induced during loading. Using CFRP laminates on the concrete slab for continuous composite beams is more effective in enhancing the beam capacity in comparison with using the external post-tension. However, reductions in the beam ductility were obtained.
]]>CivilEng doi: 10.3390/civileng4020027
Authors: Vahid Khiali Hugo Rodrigues
This review aims to investigate the recent advancements in the performance of earthquake-damaged reinforced concrete structures subjected to fire loading and the damages that are induced by fire to reinforced concrete structural elements with damage due to seismic loads. The first part of the paper provides a general understanding of the Post-Earthquake Fire (PEF) effect on reinforced concrete structures, and some statistics regarding the previous earthquake casualties and amounts of destruction in different regions of the world are addressed. In the second part of the investigation, an in-depth review of the experimental and numerical procedures of PEF analysis in concrete columns, beams, slabs, and full-scale RC frames and the types of damages in RC members due to PEF have been presented, giving a general review of the results and conclusions in previous research in PEF in different reinforced concrete structures. In the end is discussed the concept of hybrid fire simulation, its applications in engineering problems, the methodologies that consider full interaction effects as well as recent breakthroughs in studying PEF using Real-Time Hybrid Simulation.
]]>CivilEng doi: 10.3390/civileng4020026
Authors: Luis G. Baltazar Antonio Morais
The aim of this work is to determine how the mechanical and physical properties of render mortars, in particular their moisture performance, are affected by the application of paint. In this study, three commercial paints, hydro-pliolite-based paint, acrylic paint and silicate paint, were applied as coating layers on render mortars formulated with different binders. The choice of the binders used (hydrated lime, natural hydraulic lime and cement) was related to the functional requirements that the renders have to fulfil according to the type of buildings where they are applied (i.e., new or old buildings). Firstly, the hardness and surface cohesion of the different painted and unpainted renders were analysed in order to investigate the effect of the type of paint on the mechanical strength of the render surface. The influence of the paints on the moisture behaviour of the renders was then investigated using the water capillarity test, the water vapour permeability test and the drying test. The results show that all the paints studied can cause a significant change in the behaviour of the renders in terms of moisture transport phenomena. Nevertheless, it can be concluded that acrylic paint has the greatest resistance to water absorption, but it is also the paint with the higher resistance to water vapour diffusion. Hydro pliolite paint was found to be adequate from the point of view of reducing moisture accumulation and is the most recommended for old buildings with hydrated lime or hydraulic lime-based renders.
]]>CivilEng doi: 10.3390/civileng4020025
Authors: Asiya Alawi Abdalrhman Milad Diego Barbieri Moad Alosta George Uwadiegwu Alaneme Qadir Bux alias Imran Latif
Portland cement (PC) is a common material used in civil infrastructure engineering. Cement production emits roughly 2.2 billion tons of CO2 per year, contributing 8% of global emissions in 2016. This contributes to almost half of the calcination process, and together with thermal combustion, clinker generation could be responsible for 90% of the sector’s emissions. One effective technique for dealing with these industrial by-product wastes is to employ them to make cement replacements such as concrete and mortar, which can be used in a variety of applications. As a result, the purpose of this research is to review the current advancements, challenges, and future perspectives on the utilization of agro-industrial waste (AIW) produced around the world in cement-based products. Geopolymers (GPs), on the other hand, reduce carbon dioxide emissions and have the potential to be a complete or partial replacement for PC in the construction sector. The GP technology enables the use of AIW in combination with an alumina–silicate (A–S) phase with minimal environmental impact. GP-cement is mostly produced by activating alkali silicates or alkali sols with secondary raw materials such as calcined clays, fly ash (FA), zeolite, metakaolin, etc. Mixing various resource materials, including additives, A–S, and alkali sols, alkali concentrations, optimizing the curing temperature, the SiO2/Na2O ratio, microstructural behavior, and other factors, results in GP-cement with outstanding mechanical and durability characteristics. The review concludes that AIW-based geopolymer composites have shown promising results in terms of their mechanical properties, durability, and environmental sustainability, which makes them emerge as promising future building materials with applications in a wide range of industries.
]]>CivilEng doi: 10.3390/civileng4020024
Authors: Nemanja Dobrota Aleksandar Stevanovic Yifei Yang Suhaib Alshayeb
Transportation agencies periodically conduct signal retiming (i.e., optimization) to ensure efficient signal operations. Previous studies introduced the notion of the “resonant cycle length” (RCL), which is based on the premise that a good progression of traffic on the corridor mainline for various volume fluctuations can be achieved with an appropriate value of cycle lengths, where all other signal timing parameters (splits, offsets and phase sequences) remain unaltered. Several follow-up studies brought many inconsistencies in the previously introduced concept. For instance, authors would investigate the existence of the RCL by evaluating the performance of signal timing plans for not only coordinated movements (side streets and coordinated movements together), but would optimize all signal timing parameters (not only cycle lengths) while investigating. This study sheds light on the RCL concept and highlights the importance of all signal timing parameters for signal performance. In addition, we introduce a concept called the resonant signal timing plan (RSTP) as a refinement for the RCL, which represents a combination of signal timing parameters that (unaltered) retain an acceptable performance for a variety of traffic conditions. Results show that different sets of signal timing parameters cause plans to be resonant depending on the evaluation type.
]]>CivilEng doi: 10.3390/civileng4020023
Authors: Xian-Kui Zhu
Most transmission pipelines are buried underground per regulations, and external corrosion is the leading cause of failures of buried pipelines. For assessing aged pipeline integrity, many corrosion assessment models have been developed over the past decades. This paper delivers a technical review of corrosion assessment models for determining the remaining strength of thin- and thick-walled pipelines containing corrosion defects. A review of burst prediction models for defect-free pipes is given first, including the strength- and flow-theory-based solutions, and then of those for corroded pipes. In terms of the reference stress, the corrosion models are categorized into four generations. The first three generations correspond to the flow stress, ultimate tensile stress (UTS), and a combined function of UTS and strain-hardening rate, while the fourth generation considers the wall-thickness effect. This review focuses on recent advances in corrosion assessment methods, including analytical models and machine learning models for thick-walled pipelines. Experimental data are used to evaluate these burst pressure prediction models for defect-free and corroded pipes for a wide range of pipeline steels from low to high grades (i.e., Grade B to X120). On this basis, the best corrosion models are recommended, and major technical challenges and gaps for further study are discussed.
]]>CivilEng doi: 10.3390/civileng4020022
Authors: Elena Makisha
The transition to a design based on information modeling has paved the way for automated verification of project documentation. The most complicated type of design documentation check is the assessment of compliance with the requirements of regulatory documents since its automation requires the translation of statements written in natural language into a machine-readable format. At the same time, building codes and regulations should be suitable for translation into machine-readable form. However, a large number of provisions presented in regulatory documents cannot be subjected to automated verification due to their specific features. This study aimed to analyze the suitability of the regulatory provisions to be translated into a machine-readable format, identify limiting factors, and establish recommendations to avoid these factors. This study was conducted based on the example of the code of rules for “Residential Apartment Buildings” (SP 54.13330.2016) applied in the Russian Federation. During the research, a previously developed algorithm that generates rules for checking building information models and is based on the RuleML language was applied to the provisions of the standard above to identify statements that can and cannot be translated. As a result, 356 statements were received, which were divided into five groups: requirements suitable for translation into a machine-readable format, requirements containing links to other documents (regulatory and not only), requirements of uncertain interpretation, requirements that cannot be verified based on an information model, and informative requirements. For the first group of statements, there were examples given for both the statements and the rules derived from them. For the other four groups, examples of statements were supplied with factors preventing the translation of requirements into a machine-readable format and solutions on how to avoid these factors. An analysis of the distribution of statements (related to the above-mentioned groups) by sections of the standard showed that a significant part of the requirements is suitable for translation into a machine-readable format. The possible obstacles to translation can be overcome by attracting experts and using programming tools. The paper also makes recommendations on how to arrange new standard structures.
]]>CivilEng doi: 10.3390/civileng4020021
Authors: Ilham I. Mohammed Nazim Abdul Nariman Pshtiwan Shakor Osama Ismail Kozhin Rizgar
Reusing waste is one of the most recent topics and one of the main contributors to sustainability. It is known that concrete is one of the most common materials to produce different types of construction members around the world. That is due to mainly its low cost, availability, long period of durability, and ability to withstand harsh environments. On the other hand, due to the rapid changes that have happened in the last few decades in the production of decorative materials, some material types of cladding are used for decoration purposes, such as Styrofoam (EPS) (trade name “Astropol”), which is developed from disposal materials. Discovering and implementing a method of reusing these wastes in concrete is beneficial for the environment to reduce waste around the globe. In the current study, Styrofoam (Astropol) waste was used as a replacement for fine aggregate since concrete structures contain this material in their composition. It is important to test these materials for fire resistance and expose them to an elevated temperature in order to discover the post-fire mechanical properties of the composite material. The experimental result showed that the post-fire compressive strength of concrete containing different ratios of EPS (Astropol) increases compared to conventional concrete. The compressive strengths were 19.94 MPa, 19.295 MPa, 16.806 MPa, and 17.66 MPa for 0%, 15%, 25%, and 50%, respectively, while the post-fire indirect tensile strength for all specimens containing EPS reduced as the fire duration and temperature increased.
]]>CivilEng doi: 10.3390/civileng4010020
Authors: Benjamin Stewart Hiram Moya Amit U. Raysoni Esmeralda Mendez Matthew Vechione
The mathematical study known as queueing theory has recently become a major point of interest for many government agencies and private companies for increasing efficiency. One such application is vehicle queueing at an international port-of-entry (POE). When queueing, fumes from idling vehicles negatively affect the overall health and well-being of the community, especially the U.S. Customs and Border Protection (CBP) agents that work at the POEs. As such, there is a need to analyze and optimize the border crossing queuing operations to minimize wait times and number of vehicles in the queue and, thus, reduce the vehicle emissions. For this research, the U.S.–Mexico POE located at The Gateway International Bridge in Brownsville, Texas, is used as a case study. Due to data privacy concerns, the hourly wait times for vehicles arriving at the border had to be extracted manually each day using a live wait time tracker online. The data extraction was performed for the month of March 2022. Using these wait times, a queueing simulation software, SIMIO, was used to develop an interactive simulation model and calibrate the service rates. The output from the SIMIO model was then used to develop an artificial neural network (ANN) to predict hourly particulate matter content with an R2 of 0.402. From the ANN, a predictive equation has been developed, which may be used by CBP to make operational decisions and improve the overall efficiency of this POE. Thus, lowering the average wait times and the emissions from idling vehicles in the queue.
]]>CivilEng doi: 10.3390/civileng4010019
Authors: Jonny Nilimaa Rasoul Nilforoush
Tensile strength is a crucial property for the function, safety and durability of all concrete structures. The general procedure to assess the tensile properties of concrete from existing structures is to perform indirect tests and predict the tensile strength based on established empirical relationships. In this study, the direct tensile strength of concrete was investigated using cylindrical specimens. The aim of the study was to propose, test and evaluate a general method for direct tensile tests of concrete from existing structures. A total of 16 specimens were tested under deformation-controlled tensile-loading until failure. The concrete samples were prepared with 10 or 15 mm grooves at mid-height to obtain cracking in the groove region, where the crack-opening sensors were installed. The load and corresponding deformation were recorded continuously during the test to obtain the load–crack-width relationship of the concrete. The tests showed that the method can be used to assess the tensile properties of concrete from existing structures. The study provides important insights regarding the assessment of direct tensile strength of concrete and the results can be used to improve the structural health monitoring of existing structures and thereby ensure their safety and durability.
]]>CivilEng doi: 10.3390/civileng4010018
Authors: Yiwei Hu Prashidha Khatiwada Hing-Ho Tsang Scott Menegon
This paper is aimed at serving the needs of structural engineering researchers who are seeking accelerograms that realistically represent the time histories of earthquake ground in support of their own investigations. Every record is identified with a specific earthquake scenario defined by the magnitude–distance combination and site conditions; the intensity of the presented records is consistent with ultimate limit state design requirements for important structures in an intraplate region. Presented in this article are accelerograms that were generated on the soil surface of two example class Ce sites and two example class De sites based on site response analyses of the respective soil column models utilizing bedrock excitations as derived from the conditional mean spectrum (CMS) methodology. The CMS that were developed on rock sites were based on matching with the code spectrum model stipulated by the Australian standard for seismic actions for class Be sites at reference periods of 0.2, 0.5, 1 and 2 s for return periods ranging from 500 to 2500 years. The reference to Australian regulatory documents does not preclude the adoption of the presented materials for engineering applications outside Australia. To reduce modeling uncertainties, the simulation of the soil surface ground motion is specific to the site of interest and is based on information provided by the borelogs. The site-specific simulation of the strong motion is separate to the CMS-based accelerogram selection–scaling for obtaining the bedrock accelerograms (utilizing strong motion data provided by the PEER). The decoupling of the two processes is a departure from the use of the code site response spectrum models and has the merit of reducing modeling uncertainties and achieving more realistic representation of the seismic actions.
]]>CivilEng doi: 10.3390/civileng4010017
Authors: Ryan Hoult António A. Correia João Pacheco de Almeida
Reinforced concrete (RC) core walls are commonly used to provide buildings with lateral and torsional resistance against the actions of wind and earthquakes. In low-to-moderate seismic regions, it is not unusual to find a single peripheral core wall that alone should resist these actions, where the torsional (rotational) twist cannot be neglected. It has previously been difficult to have confidence in simulating the axial-flexure-torsion behavior of these RC core walls, primarily due to: (i) some types of modelling approaches being unable to appropriately account for the shear-flexural action, as well as torsional response; and (ii) the scarcity of experimental data, particularly for walls under torsional loads, which would be required to validate such models. In this research, beam-truss models (BTMs), which correspond to an interesting compromise between detailed modelling and practical applications, were used to simulate the in-plane and diagonal flexural response of RC U-shaped walls. Furthermore, the global torque-rotation results from a recent experimental wall test provided the evidence to further validate this powerful modelling technique. A case study building, comprising an RC U-shaped core wall structure with varying eccentricity values, was evaluated for an earthquake event with a 2475-year return period in the city of Melbourne, Australia, using the capacity spectrum method. Nonlinear static pushover analyses showed that, depending on the magnitude of torsion, the in-plane flexural strength and displacement capacity can be significantly reduced. The results from this research emphasize the importance of including torsional actions in the design and assessment of reinforced concrete buildings.
]]>CivilEng doi: 10.3390/civileng4010016
Authors: Xiangzhe Weng Ryan D. Hoult Elisa Lumantarna
This paper aims to show the application of site-specific response spectra in the analysis of buildings that are supported by lightly reinforced precast concrete walls. Previous surveys on load-bearing precast reinforced concrete walls in multi-storey buildings in low-to-moderate seismic regions have found that many existing precast walls are lightly reinforced with a connection reinforcement ratio less than the wall reinforcement ratio. When these precast walls are subjected to reversed cyclic loads, the lateral response is typically controlled by rocking and the ultimate performance is governed by the ruptures of connection dowels. This paper uses moment–curvature analyses in combination with plastic hinge analyses to evaluate the force–displacement capacity of planar lightly reinforced load-bearing precast walls. The seismic performance of a building supported by these lightly reinforced precast walls can then be assessed by superimposing the capacity curve and the inelastic site-specific response spectra developed for the building site. The proposed analytical approach is illustrated through a case study building. By comparing a lightly reinforced precast wall with a comparable limited ductile reinforced concrete wall, it is also found that, although these two walls exhibit similar force capacities, the ultimate displacement capacity of the lightly reinforced precast wall is significantly lower. This finding highlights the potential seismic vulnerability of lightly reinforced precast walls in some existing buildings.
]]>CivilEng doi: 10.3390/civileng4010015
Authors: Yao Hu Prashidha Khatiwada Elisa Lumantarna Hing Ho Tsang
This paper aims at giving structural designers guidance on how to transform seismic demand on a building structure from two-dimensional (2D) to three-dimensional (3D) in an expedient manner, taking into account amplification of the torsional actions. This paper is to be read in conjunction with either paper #3 or #4. Torsional amplification of the drift demand in a building is of major concern in the structural design for countering seismic actions on the building. Code-based seismic design procedures based on elastic analyses may understate torsional actions in a plan of asymmetric building. This is because the inability of elastic analyses to capture the abrupt increase in the torsional action as the limit of yield of the supporting structural walls is surpassed. Nonlinear dynamic analysis can provide accurate assessment of torsional actions in a building which has been excited to respond in the inelastic range. However, a 3D whole building analysis of a multi-storey building can be costly and challenging, and hence not suited to day-to-day structural design. To simplify the analysis and reduce the scale of the computation, closed-form expressions are introduced in this paper for estimation of the Δ3D/Δ2D drift demand ratio for elastic conditions when buildings are subjected to moderate-intensity ground shaking. The drift demand of the 3D model can be estimated as a product of the 2D drift demand and the Δ3D/Δ2D drift demand ratio. In dealing with higher-intensity ground shaking causing yielding to occur, a macroscopic modelling methodology may be employed. The estimated Δ3D/Δ2D drift demand ratio of an equivalent single-storey building is combined with separate analysis for determination of the 2D drift demand. The deflection profile of the multi-storey prototype taking into account 3D effects, including torsional actions, is hence obtained. The accuracy of the presented methodologies has been verified by case studies in which drift estimates generated by the proposed calculation procedure were compared against results from whole building analyses, employing a well-established computer software.
]]>CivilEng doi: 10.3390/civileng4010014
Authors: Amir Behravan M. Tyler Ley Dan Cook Qinang Hu Anna Rywelski Russell Brorsen
The penetration of ions plays an important role in the durability of concrete structures. This study aims to establish the feasibility of using dental X-ray equipment to measure the concentration and penetration of iodide within cementitious systems. This technique is known as checking ion penetration (CHIP). This test uses iodide as a tracer because it has a high electron density, and so it can be observed with X-ray imaging as it penetrates the concrete. Concentration profiles from CHIP are used to calculate the apparent diffusion coefficient (Dac). These results are similar to measurements from bulk chloride ponding tests. The Dac is used to predict the service life or evaluate the quality of an as-built concrete structure or concrete mixture. Because of the wide availability of dental equipment, CHIP shows promise to be used as a method to measure the in-place quality control of the concrete.
]]>CivilEng doi: 10.3390/civileng4010013
Authors: Tingsong Chen Nobuyoshi Yabuki Tomohiro Fukuda
The construction industry holds the worst safety record compared to other industrial sectors, and approximately 88% of accidents result in worker injury. Meanwhile, after the development and wide application of deep learning in recent years, image processing has greatly improved the accuracy of human motion detection. However, owing to equipment limitations, it is difficult to effectively improve depth-related problems. Wearable devices have also become popular recently, but because construction workers generally work outdoors, the variable environment makes the application of wearable devices more difficult. Therefore, reducing the burden on workers while stabilizing the detection accuracy is also an issue that needs to be considered. In this paper, an integrated sensor fusion method is proposed for the hazard prevention of construction workers. First, a new approach, called selective depth inspection (SDI), was proposed. This approach adds preprocessing and imaging assistance to the ordinary depth map optimization, thereby significantly improving the calculation efficiency and accuracy. Second, a multi-sensor-based motion recognition system for construction sites was proposed, which combines different kinds of signals to analyze and correct the movement of workers on the site, to improve the detection accuracy and efficiency of the specific body motions at construction sites.
]]>CivilEng doi: 10.3390/civileng4010012
Authors: Hendrik Morgenstern Michael Raupach
The durability of concrete structures is essential for reliable infrastructure. Although many deterioration models are available, they are rarely applied in situ. For existing structures in need of repair or durability assessment, this is also the case for Building Information Modeling (BIM). However, both BIM and durability modeling hold great potential to both minimize expended resources and maximize the reliability of structures. At the Institute for Building Materials Research (ibac) at RWTH Aachen University, a novel approach to the calibration of deterioration models using Bayesian inference iteratively in a BIM model enriched with machine-readable diagnosis data to achieve a predictive decision support tool is being developed. This paper demonstrates the digital workflow, validates the proposed approach, and expresses the added value for the planning of repair measures.
]]>CivilEng doi: 10.3390/civileng4010011
Authors: Rami Khalifah Mena I. Souliman Mawiya Bin Mukarram Bajusair
One of the most common pavement distresses in flexible pavement is rutting, which is mainly caused by heavy wheel load and various other factors. The prediction of rutting depth is important for safe travel and the long-term performance of pavements. Factors that are considered in this paper for the prediction of rut depth are Temperature, Equivalent Single Axle Load, Resilient modulus, and Thickness of hot mixed asphalt. The input data for all factors are collected from the Long-Term Pavement Performance Information Management System for the state of Texas. Regression analysis is performed for dependent and independent variables to obtain the empirical relationship. In various fields of civil engineering, artificial neural networks have recently been utilized to model the qualities and behavior of materials and to determine the complicated relationship between various properties. An Artificial Neural Network is used to develop a predictive model to predict the rutting depth. A total number of 70 observations were considered for the predictive model. A mathematical relation is developed and verified between rut depth and variable input data.
]]>CivilEng doi: 10.3390/civileng4010010
Authors: Noemi Schclar Leitão Eloísa Castilho M. Luísa Braga Farinha
During the first filling, the reservoir is gradually raised in multiple stages. At each stage, the filling is paused to allow adequate time for monitoring and evaluating the performance of the dam and its foundation. The analysis of the monitored behavior and assessment of security conditions is performed by comparing the values measured by the monitoring system installed in the dam with the values predicted by numerical models representing the structural behavior, the material properties, and the loads. This article addresses the main aspects related to the safety control of concrete arch dams during the first filling of the reservoir. Special attention is given to the nonlinear behavior induced by the opening/closing of the contraction joints. An example of numerical simulation of the behavior of an arch dam during the first filling of the reservoir is also presented. The validation of the computed temperatures, the induced displacements and the induced stresses was performed by comparison with the values measured with the monitoring system installed in the dam.
]]>CivilEng doi: 10.3390/civileng4010009
Authors: Prashidha Khatiwada Yiwei Hu Elisa Lumantarna Scott J. Menegon
This paper is aimed at giving structural designers guidance on how to make use of elastic site-specific response spectra for the dynamic modal analysis of a structure in support of its structural design. The use of response spectra in support of the pushover analysis of an RC building forming part of the non-linear static analysis procedure (that can be used to predict seismic demand without relying on the code-stipulated default R factor) is also presented. Seismic analysis of structures based on the use of site-specific response spectra can help to achieve a more optimised, and cost-effective, structural design compared to the conventional approach employing a response spectrum model stipulated by the code for different site classes. Currently, the methodology is only adopted in major projects in which enough resources are available to engage experts who are skilled in operating the procedure; thus, the use of site-specific response spectra in structural engineering practice is still limited despite the merits of the procedure. Deriving a site-specific response spectrum requires a database of representative ground motion records to be developed. Extra analytical tasks to be undertaken include the processing of bore log data, site response analyses, and selection/scaling of bedrock accelerograms for input into site response analyses. Guidelines for implementing this design methodology are currently lacking. To promote the wide adoption of site-specific seismic design, this article presents the procedure for developing the required site-specific design spectra, as well as guidelines for applying these spectra for seismic design based on analyses of linear, or nonlinear, models of the building. Non-linear analysis can be accomplished by dealing with macroscopic models as illustrated in a case study.
]]>CivilEng doi: 10.3390/civileng4010008
Authors: Ahmadreza Torabipour Nima Asghari Homa Haghighi Shaghayegh Yaghoubi Girum Urgessa
This study presents finite element analysis of double split tee (DST) connections with high-strength steel bolts and coupled split tee sections, to evaluate various cyclic response parameters and elements. The investigation included quantifying connection behavior and hysteretic response, damage indexes, and failure modes. Over 40 specimens were simulated in ABAQUS under cyclic loading, including shape memory alloy (SMA)-built specimens. In the post-analysis phase, the T-stub thickness, the T-stub yield strength, the bolt preload and bolt number, and the stiffener type and stiffener material for the most significant parts of the DST connection were calculated. Simulation results showed that a lower ultimate moment yielded fewer needed stem bolts. The energy dissipation (ED) capacity increased as the horizontal distance between the stem bolts decreased. Additionally, increasing the strength of the bolt and T-stub by 15% resulted in a 3.86% increase in residual displacement (RD) for the bolt and a 1.73% decrease in residual displacement for the T-stub. T-stub stiffeners enhanced ED capacity by 31.7%. SMA materials were vulnerable to mode 1 failure when used in T-stubs, bolts, or stiffeners. However, the use of SMA increased the rate of energy dissipation. Adding stiffeners to the T-stubs altered the failure indexes and improved the pattern of failure modes. In addition, stiffeners decreased the rupture and pressure indexes. As a result, the failure index of a T-stub shifted from brittle failure to ductile failure.
]]>CivilEng doi: 10.3390/civileng4010007
Authors: Louis Aurier Munzer Hassan Jan Jaworski Lotfi Guizani
The application of Accelerated Bridge Construction methods (ABC) to build, renovate and rehabilitate aging bridges is most likely to reduce the economic and social impacts of projects. This is especially relevant in countries with severe winter climates, where bridge construction is typically interrupted during the winter period. The objective of this study is to present the state of the art related to elements, systems, connections and materials used for bridge superstructures in ABC projects and to highlight their adaptability to cold or northern climate countries. The literature review and presentation of results are based on the gathering of Prefabricated/Precast Bridge Elements and Systems (PBES) used for ABC projects in North America and which are also used in many countries around the world. Following this inventory, and after grouping the PBES, connections and materials, the authors were able to identify the possibility of adapting the ABC method for countries with cold and northern climates. Products that can be used down to −6 °C for connections are presented, and future research orientations are proposed.
]]>CivilEng doi: 10.3390/civileng4010006
Authors: Zoltán Gyurkó Tamás Kovács Levente Jakab Rita Nemes
The present research deals with the cyclic and standard pull-out resistance of deformed steel bars embedded in lightweight and normal concrete. This paper is a continuation of a previous paper, where the experimental results are detailed. In the present paper, the experimental results are set against the formulas and the diagrams provided by the Eurocode standard and the Model Code 1990, and then a comparative discussion is performed. In the case of cyclic loading, the damage defined by the Palmgren–Miner hypothesis, as well based on the recommendations of various national annexes of Eurocode and the Model Code, is calculated. A multiplier corresponding to the maximum load is calculated, which indicates by how much the applied load should be multiplied to obtain a damage value equal to 1.
]]>CivilEng doi: 10.3390/civileng4010005
Authors: CivilEng Editorial Office CivilEng Editorial Office
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]]>CivilEng doi: 10.3390/civileng4010004
Authors: Hyunjin Ju Alina Serik
This study discusses the torsional capacity of recycled coarse aggregate (RCA) reinforced concrete beams under pure torsion based on the experimental findings available in the literature. The experimental data on RCA specimens were collected and compared with the conventional concrete specimens with key variables, such as compressive strength and longitudinal and transverse reinforcement ratios, as those variables affect the torsional capacity of reinforced concrete beams. Overall, the database consisted of experimental results from 30 RCA specimens and 256 natural coarse aggregate (NCA) specimens. The result shows that specimens with a 100 % replacement ratio have the lowest strength. In addition, as the structural mechanism of torsion is similar to the shear mechanism in reinforced concrete beams, a comparative analysis was performed with RCA specimens subjected to shear force. It was concluded that the RCA has a similar effect in strength reduction for the specimens subjected to torsion or shear with a 100% replacement ratio. However, further study and experimental evidence are required to confirm the applicability of the recycled aggregate to produce and design the structural members.
]]>CivilEng doi: 10.3390/civileng4010003
Authors: Mohamed Algamati Abobakr Al-Sakkaf Eslam Mohammed Abdelkader Ashutosh Bagchi
Nowadays, due to environmental changes, the condition of buildings can be in danger. In order to protect the performance of existing buildings, it is important to investigate the seismic behaviour of building structure subjected to earthquake excitation. In addition, it is important to study the advanced level of ductile design recommended by current codes. In the immediate future, lateral load resistance needs to be evaluated precisely. For the purpose of analyzing the seismic responses of reinforced concrete (RC) buildings in this project, 6- and 12-story frames of representative buildings are modeled in this research paper. The response spectrum analysis is deployed for a multi-degree-of-freedom system exposed to seismic waves (earthquake) in the City of Vancouver. Hence, the seismic nature of Vancouver City is emulated by the resulting response spectra using ground motion records (GMR). Ultimately, for concluding the average displacement as well as the base shear of the structures, a time-history analysis is investigated. In this regard, the SAP2000 and ETABS software are utilized for analyzing seismic performances. In addition, a comparison is presented between previous studies that used the IDARC2D software and the proposed results that used the ETABS software. It is found that the applied cases are not overlapping the limit of the NBCC 2015 Code. Consequently, after investigation, it is evident that the 3D software is much more accurate than the 2D software.
]]>CivilEng doi: 10.3390/civileng4010002
Authors: Chaofan Yi Zheng Chen Jiamin Yu Vivek Bindiganavile
This study models concrete as a multi-phase system that comprises the mortar, coarse aggregates, and interfacial transition zones (ITZs). The diffusivity and the volumetric fraction of these phases are considered to propose a three-phase diffusion–reaction model to simulate the external sulphate attack. Furthermore, the parametric analysis alongside the sensitivity analysis is carried out to quantify the effect of these phases on the expansive cracking in concrete when exposed to a sulphate-rich environment. The results show that mortar dominates the sulphate ingress and the ensuing distress, while the ITZ is found to be least significant. Due to its significantly low permeability, the coarse aggregate may act as a “deceleration strip” or a “dam”, which in turn obstructs the sulphate penetration. More importantly, this effect is further noted to evolve with a decrease in the diffusivity and a rise in the volumetric fraction of coarse aggregates. As for ITZ, its volume fraction may play a more dominant role than its diffusivity on sulphate attack in concrete.
]]>CivilEng doi: 10.3390/civileng4010001
Authors: Pierre Rossi
This study presents analysis of two types of experimental test related to the crack propagation in concrete specimens subjected to high-sustained loading levels and quasi-static loadings. The concept of the equivalent crack length is introduced to perform this analysis. Even though this analysis is partial, it shows the influence of loading rate conditions on the crack process rate. This result shows that, in the domains of low and very low loading rates, the concrete mechanical characteristics linked to the cracking process (for example, tensile strength, post-cracking behaviour, etc.) are dependent on the loading rates applied to the specimens for determining them.
]]>CivilEng doi: 10.3390/civileng3040064
Authors: Golam Kabir Shahid Azam
Civil infrastructure supported by expansive clays is severely affected by extensive volumetric deformations. The reliability prediction of such facilities is quite challenging because of the complex interactions between several contributing factors, such as a scarcity of data, a lack of analytical equations, correlations between quantitative and qualitative information, and data integration. The main contribution of this research is the development of a modeling approach based on the Bayesian belief network. The modeling results highlight that facility age is the most critical parameter (23% variance), followed by facility type (1.37% variance), for all the investigated types of infrastructure, namely road embankments, buried pipelines, and residential housing. Likewise, the results of sensitivity analysis and extreme scenario analysis indicate that the new method is capable of predicting infrastructure reliability and the assessments were found to be in agreement with expected field behavior. The proposed model is useful in decision making related to civil infrastructure management in expansive clays.
]]>CivilEng doi: 10.3390/civileng3040063
Authors: Henrik Matz Martin Empelmann
In response to housing shortages in densely inhabited urban areas, there is a search for structural engineering solutions for serial and modular construction. Prefabricated concrete columns can make an important difference. Using industrial manufacturing processes, it is possible to produce highly loadable, durable and true-to-size columns that enable accelerated construction progress and dismantling or reuse of the components at the end of the structure’s economic life. However, there are challenges in designing the detachable connection between highly loaded columns due to an undesired reduction of the load-bearing capacity on the one hand and a high sensitivity to geometrical deviations on the other hand. To investigate the load-bearing and deformation behaviour of butt-jointed columns, large-scale component tests as well as three-dimensional numerical analyses using the finite element method were carried out. The analyses show that measures to increase the stiffness of the joint, such as thicker steel plates, lower mortar thickness, etc., lead to an increase of the ultimate load. It could also be demonstrated that butt-jointed columns are very sensitive to unevenness of the end faces. Finally, the investigations allow first conclusions on the design and detailing of detachable compression connections between prefabricated concrete columns.
]]>CivilEng doi: 10.3390/civileng3040062
Authors: Bandar Moshabab Alqahtani Wael Alruqi Siddharth Bhandari Osama Abudayyeh Hexu Liu
Mental health concerns are surging worldwide and workers in the construction industry have been found to be particularly vulnerable to these challenges. Stress, depression, addictions, suicides, and other key indicators of poor mental health have been found to be highly prevalent among construction workers. Critically, researchers have also found a link between how stress in the workplace impacts the overall safety performance of an individual. However, the burgeoning nature of the research has stifled the determination of feasible and actionable interventions on jobsites. This paper aims to analyze the relationship between work-related stressors found on construction jobsites and self-reported injury rates of workers. To accomplish this goal, a meta-analysis methodology was used, wherein a comprehensive literature search was conducted to identify key work-related stressors and questionnaires used in the construction industry’s safety domain to assess stress. Using a formal meta-analysis approach that leverages the findings from past studies, a more holistic determination of the relationship between work-related stressors and injury rates among workers was performed. Ninety-eight studies were reviewed, and seven were selected that fulfilled pre-determined validated inclusion criteria for eligibility in the meta-analysis. The results revealed 10 salient work-related stressors among construction workers. Of these ten, seven work-related stressors were identified as significant predictors of injury rates among workers: job control, job demand, skill demand, job certainty, social support, harassment and discrimination, and interpersonal conflicts at work. This study represents a significant first step toward formally identifying work-related stressors to improve working conditions, reduce or eliminate injuries on construction sites, and support future research.
]]>CivilEng doi: 10.3390/civileng3040061
Authors: Stewart MacLennan Fernando C. R. Almeida Agnieszka J. Klemm
In an attempt to increase sustainability of construction materials, both ground granulated blast-furnace slag (GGBS) and, less popular, copper slag (CS) can be used in alkali-activated composites. However, such composites are often more susceptible to cracking, triggered by the self-desiccation processes. The addition of superabsorbent polymers (SAP) may enable internal curing of concrete and prevent excessive cracking. Thus, this paper aims to evaluate the effectiveness of SAP as an internal curing agent for alkali-activated slag mortars containing GGBS and CS. The samples were activated by sodium silicate using 6.5% Na2O by mass of precursor. The evaluation was based on the analysis of mechanical properties, autogenous shrinkage, and water absorption capacity of two types of SAPs. Depending on the type of polymer, a higher alkali concentration in SAP solutions speeds up early age reactions up to 7 days. After this period, SAP collapses and reactions follow at the same pace as the reference sample. In the presence of CS, SAP with higher absorption and smaller particles well-distributed in the mix leads to a higher extension of reactions, observed in higher values of autogenous shrinkage (AS). This results in increased compressive strength of GGBS-CS mortars, achieving values 8.8% greater than the reference sample (without SAP) at 6 months. Although its leads to higher cracking susceptibility, SAP can improve mechanical properties and promote new applications for sustainable material containing copper slag.
]]>CivilEng doi: 10.3390/civileng3040060
Authors: Alaa El-Sisi Ahmed Hassanin Fahad Alsharari Narek Galustanian Hani Salim
The fiber-reinforced polymeric (FRP) composite can be joined by adhesive bonding or mechanically fastening the composite element. Carbon fiber-reinforced polymers (CFRP) and glass fiber-reinforced polymers (GFRP) are the most common types of polymers. Mechanically fastened or bolted joints do not need treatments, and the surface temperature and other environmental effects such as humidity do not affect its strength. In this research, the previous research that describes the behavior of the composite bolted joint (CBJ) is presented and summarized including the modes of failure of the CBJ, and the experimental works that explain the bearing failure (BF) of the CBJ. In addition, the effects of bolt clamping force (BCF) and techniques that are used to simulate the progressive failure and damage in composite materials and finite element simulation works are surveyed.
]]>CivilEng doi: 10.3390/civileng3040059
Authors: Andrew Pan Murray Grabinsky
Cemented paste backfill (CPB) plays an increasingly important role in the mining industry due to its operational and environmental benefits. CPB is placed in the mined-out stope to form a self-supporting structure. The strength and stability of the CPB is of great concern in its engineering applications. Indeed, CPB must remain stable during the extraction of adjacent stopes to ensure the safety of the mine operations. Although significant research has been conducted on the shear properties of CPB, there are limited studies on its post-failure behavior, in particular the yield characteristics of CPB. This paper presents the finding on the post-peak and yield property of CPB. The study is conducted on three cemented contents and six stress intervals based on the mining practice and field study. The results show that CPB exhibits dilative behavior under strain softening and contractive property under strain hardening conditions. Our study demonstrates that pure frictional resistance could exceed the cohesion strength at high stress levels.
]]>CivilEng doi: 10.3390/civileng3040058
Authors: Charlotte Thiel Johanna Kratzer Benedikt Grimm Thomas Kränkel Christoph Gehlen
With steadily rising CO2 concentrations in the ambient air and fast-changing concrete compositions with reduced clinker contents, the availability of reliable and accelerated concrete carbonation tests is of crucial importance to design durable structures. This paper focuses on the effects of moisture under accelerated conditions and the effects of different CO2 exposure conditions. Mortar prisms incorporating three different cement types were cured and stored at either 50% or 65% relative humidity (RH). Afterwards, the prisms were carbonated at different ambient humidities (50, 57 and 65%), different CO2 concentrations (0.04, 1 and 3 vol.%) and complemented by a series of tests at increased gas pressure (2 barg). High-resolution test methods were used to explain the underlying carbonation mechanisms. The results show that pre-conditioning for two weeks—as currently suggested by the European Standard—seems to be too short because the initial inner moisture content severely affects the carbonation rate. Relative humidity during carbonation of 57% led to higher carbonation rates compared to 50% and 65%. In addition, climate data needs to be periodically (preferably permanently) recorded in research experiments and in laboratory testing to ensure fair interpretation of experimental results.
]]>CivilEng doi: 10.3390/civileng3040057
Authors: Yang Lu Stephen Thomas Tian Jie Zhang
Advances in the field of processing and characterization of material behaviors are driving innovations in materials design at a nanoscale. Thus, it is demanding to develop physics-based computational methods that can advance the understanding of material Multiphysics behaviors from a bottom-up manner at a higher level of precision. Traditional computational modeling techniques such as finite element analysis (FE) and molecular dynamics (MD) fail to fully explain experimental observations at the nanoscale because of the inherent nature of each method. Concurrently coupled atomic to the continuum (AtC) multi-scale material models have the potential to meet the needs of nano-scale engineering. With the goal of representing atomistic details without explicitly treating every atom, the AtC coupling provides a framework to ensure that full atomistic detail is retained in regions of the problem while continuum assumptions reduce the computational demand. This review is intended to provide an on-demand review of the AtC methods for simulating thermo-mechanical behavior. Emphasis is given to the fundamental concepts necessary to understand several coupling methods that have been developed. Three methods that couple mechanical behavior, three methods that couple thermal behavior, and three methods that couple thermo-mechanical behavior is reviewed to provide an evolutionary perspective of the thermo-mechanical coupling methods.
]]>CivilEng doi: 10.3390/civileng3040056
Authors: Anxhelina Qorllari Thomas A. Bier
In this study, the significance of several factors in the performance of self-compacting mortar was statistically investigated. A screening design was used as a suitable design to identify the most important factors that can affect workability and compressive strength. The purpose of the study was to obtain the optimal conditions which can lead to optimal workability (slump flow, funnel time) and maximal compressive strength (2 and 28 days). Four experimental factors each at two levels, the type of supplementary cementitious material (SCM) as silica fume (SF) and metakaolin (MK); the amount of (SCM) at 5% and 15%; superplasticizer (SP) at 0.3% and 1.2% and viscosity modifying agent (VMA) at 0.05% and 0.2% were selected as potential candidates affecting the experimental outputs. The analysis of the data to obtain optimal values of the outputs was carried out by using MINITAB®. To establish the factor levels selected in this study in order to achieve optimal workability and maximal compressive strength, response optimization was applied. The predicted conditions for optimal workability were found to be 8.84% SF, 1.2% SP and 0.15% VMA. The solution proposed to maximize the compressive strength was 0.3% SP, 0.05% VMA and 9% or 9.75% SF for 2 and 28 days, respectively. By setting the factors at the specified levels, experimental values of the slump flow at 278 mm; funnel time at 8.3 s; 2- and 28-day compressive strength at 22.8 and 66.1 MPa were achieved. This resulted in the predicted and experimental values at the optimum conditions being in strong agreement.
]]>CivilEng doi: 10.3390/civileng3040055
Authors: Lutz Auersch Jiaojiao Song
Train passages over intact or damaged slab tracks on different soils were calculated by two methods. The finite element method (FEM) uses a Winkler soil under the track model by adding a thin “soil layer”. The combined finite-element boundary-element method has a continuous soil model that is included by the boundary element method. The basic results are the distributions of the track (rail, track plate, and base layer) displacements along the track for a single axle load. These solutions were superposed to a complete train load and transformed to time histories. The influence of track and soil parameters was analysed. The main interest was the influence of the track damage. A gap between the track plate and base layer of different lengths was studied for changes in amplitudes and widths of deflection. A best fit to measured track displacements was found so that the track damage could be identified and quantified. The FEM model with the Winkler soil cannot be fitted to the amplitude and width with the same soil parameters. Therefore, the FEBEM model is preferable for these railway track problems.
]]>CivilEng doi: 10.3390/civileng3040054
Authors: Sufian H. Natsheh Craig C. Menzemer
A new built-up closed-rib section is proposed that may improve the installation, performance, and durability of orthotropic steel bridge decks. The rib is composed of two partial or whole standard hot-rolled steel sections which are connected by a steel plate. The concept is used to design a built-up closed-rib replacement for the Benjamin Franklin Bridge deck. In addition, section performance was compared with the actual bulb section as well as a typical trapezoidal section through finite element simulations. The analyses indicate that the built-up section has smaller stress concentration values as compared with the other sections, and hence, improved fatigue resistance is expected. Finally, it is concluded that the built-up rib has potential to be considered in future orthotropic steel deck designs.
]]>CivilEng doi: 10.3390/civileng3040053
Authors: Evangelos D. Spyrou Vassilios Kappatos
Structural Health Monitoring (SHM) is a very important research domain whereby civil infrastructure is monitored. Using wireless technologies can boost SHM by providing the level of autonomous operation that is essential for these tasks. Wireless routing, with its subset, geographic routing, is an important procedure that needs to be optimised, in order to lead packets to the basestation. Occasionally, routing is susceptible to interference and collisions due to a large number of connected devices. This fact led to cooperative transmission; cooperative networks are the ones that utilise relays to accomplish the transmission of packets; thus, resulting in link quality as well as throughput increase. In this paper, we investigate the Collection Tree Protocol (CTP) to show that it can be cooperative when used in an SHM for civil infrastructure monitoring applications giving a geographical essence to the routing protocol. We do that by exploiting the fact that the CTP’s mechanism uses its tree formation for a node to transmit to the best link quality parents. An example of a cooperative model to show that it may be applied to the protocol is given. Further, Indriya testbed results of direct and cooperative transmissions are given to strengthen the case of this work, with which a scenario where the CTP exhibits better link quality when using a relay is given. A practical addition is suggested, whereby an extra field in the packet struct is proposed, which will provide the CTP with further strength to changing conditions and direct communication loss.
]]>CivilEng doi: 10.3390/civileng3040052
Authors: Md Rakibul Islam Md Tawkir Ahmed Nafis Anwari Md Hadiuzzaman Shohel Amin
This paper assesses the perception of intercity rail passengers on station facilities at Joydebpur Railway Station in Bangladesh. The ordinal logistic regression (OLR) tool was applied to analyze 1000 responses of rail passengers on 24 selected service and 5 demographic parameters. Critical consideration from the perspective of a developing country revealed six unique factors, namely Level crossing facility, Illegal establishments, Illegal shops, Floating people, Arrival performance, and Departure performance, which have never been explored in any previous studies. The regression analysis identified that 13 service quality factors significantly affected commuters’ satisfaction level, particularly the Food and drinks, Road connectivity, Sanitation, and Waiting room facility at the station. Among the five demographic factors, age, occupation, and travel frequency significantly influenced overall passenger satisfaction (OPS). The model results have also been validated through a second survey at Kamalapur Railway Station, Bangladesh. The results suggest that policymakers should focus on the elderly, financially solvent people, and frequent travelers. Additionally, refreshment facilities, road connectivity, sanitation, and waiting room facilities should be given priority, as these will heavily impact passenger satisfaction according to this study. Subsequent attributes can then be prioritized as per the attributes ranked and according to budget considerations of the authority.
]]>CivilEng doi: 10.3390/civileng3040051
Authors: Afzal Ahmed Manousos Valyrakis Abdul Razzaq Ghumman Muhammad Arshad Ghufran Ahmed Pasha Rashid Farooq Shahmir Janjua
Water scarcity is a major issue for developing countries due to the continuous increase in population every year, the major environmental challenges faced by developing countries such as Pakistan being the scarcity of water. One proposed solution to meet the requirements is to conserve water from rainfall. The process consists of the collection, storage, and use of rainwater. The rooftop rainwater harvesting systems (RWH) and rainfall harvesting system for artificially recharged water by recharge wells have received increased attention in the recent past as an efficient means of water conservation. In this study, both the systems have been analyzed for the University of Engineering and Technology Taxila (UET Taxila), Pakistan. The objective of this study is to propose a system to harvest water from the rooftops of all of the buildings on the campus and also to propose the most optimum locations of recharge wells for the artificial recharge of groundwater development. Numerous field visits were conducted after every rainfall over the past few months to identify lower elevation areas, which were further validated by the results obtained by Arc GIS. The total area of catchments available for rainwater harvesting in UET Taxila and the amount of water that could be harvested or used for replenishing groundwater reserves were also assessed in the current study. The results show that the harvestable rooftop water per month is 59% of the currently available source for watering trees and plants, and the harvestable water by recharge wells is 761,400 ft3 per year.
]]>CivilEng doi: 10.3390/civileng3040050
Authors: Roger Sathre Sai Madhavi Antharam Michela Catena
Achieving water security in South Asian cities will require a realistic and holistic understanding of the challenges that are growing in extent and severity. These challenges include the rapid rise in urban household water demand due to both overall population growth and increasing urbanization rate. Additionally, surface water supply in closed river basins is fully utilized, and there is little opportunity in these regions to increase the extraction of surface water to meet rising demands. Furthermore, groundwater extraction in most regions exceeds natural recharge rates, leading to rapidly falling annual water tables and seasonal depletion in hard rock regions and to gradually declining water tables requiring deeper wells and increased pumping effort in alluvial regions. Additionally, even in cities with abundant water resources, poorer segments of the population often face economic water scarcity and lack the means to access it. Nevertheless, there are important potential engineering opportunities for achieving water security in South Asian cities. Much withdrawn water is lost due to urban water distribution inefficiency, and a range of proven techniques exist to improve distribution. Metering of urban water can lead to structural improvements of management and billing, though the water needs of the poorest city residents must be ensured. Industrial water-use efficiency can be significantly improved in manufacturing and electricity generation. The quantities of wastewater generated in South Asia are large, thus treating and reusing this water for other purposes is a strong lever in enhancing local water security. There is limited potential for rooftop rainwater harvesting and storage, though capture-enhanced groundwater recharge can be important in some areas. Some individual inter-basin transfer projects may prove worthwhile, but very-large-scale projects are unlikely to contribute practically to urban water security. Overall, the water challenges facing South Asian cities are complex, and although no single intervention can definitively solve growing problems, numerous actions can be taken on many fronts to improve water security.
]]>CivilEng doi: 10.3390/civileng3040049
Authors: Ahmed Badawy Abobakr Al-Sakkaf Ghasan Alfalah Eslam Mohammed Abdelkader Tarek Zayed
The construction sector continues to experience significant challenges brought by new techniques and technologies. Hence, there is a dire need for construction companies to address critical issues concerning changing environmental conditions, construction innovations, market globalization and many other aspects, thereby enhancing their competitive edge. Thus, the primary goal for this research is to develop a multi-criteria decision making model that would consider and evaluate all essential factors in determining the competitiveness index of construction companies. In the developed model, three new pillars (3P) for competitiveness are introduced: (1) non-financial internal pillar; (2) non-financial external pillar; and (3) financial pillar. The 3P includes 6 categories and 26 factors that are defined and incorporated in the developed assessment model for the purpose of measuring the companies’ competitiveness. The weights for the identified factors are computed using fuzzy analytical network process (FANP) to diminish the uncertainty inherited within the judgment of the respondents. The weight of factors and their affiliated performance scores are used as an input for the preference ranking organization method for enrichment evaluation (PROMETHEE II) technique. In this regard, PROMETHEE II is undertaken as a ranking technique to prioritize any given construction company by determining its respective competitiveness index. The developed model is validated through five cases studies that reveal its potential of illustrating detailed analysis with respect to the competitive ability of construction companies. A sensitivity analysis is carried out to determine the most influential factors that affect the competitiveness of construction companies. It is anticipated that the developed evaluation model can be used in the decision-making process by all parties involved in construction projects. For instance, contractors can leverage the evaluation model in taking better decisions pertinent to the markup values. In addition, it can benefit employers in the evaluation process of contractors.
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