CivilEng

Open AccessArticle

Adjustment of Tall Building Behavior by Guided Optimization of Magneto-Rheological Damper Control Parameters

by

,

,

and

CivilEng 2023, 4(2), 596-617; https://doi.org/10.3390/civileng4020035 - 26 May 2023

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Feature Papers in CivilEng)

► Show Figures

Figure 1

Open AccessArticle

Thermal Insulation of Hybrid GFRP-Lightweight Concrete Structures

by

Mário R. T. Arruda

,

Pedro Cantor

and

Renato Bicelli

CivilEng 2023, 4(2), 584-595; https://doi.org/10.3390/civileng4020034 - 25 May 2023

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Feature Papers in CivilEng)

► Show Figures

Figure 1

Open AccessArticle

A Method to Identify the Critical Seismic Input for Curved Bridges

by

Chengcheng Tao

and

Shanyue Guan

CivilEng 2023, 4(2), 567-583; https://doi.org/10.3390/civileng4020033 - 24 May 2023

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Feature Papers in CivilEng)

► Show Figures

Figure 1

Open AccessArticle

Experimental Seismic Evaluation of Novel Buckling-Restrained Braced Frames Containing Tire-Derived Aggregate Concrete

by

,

,

,

and

CivilEng 2023, 4(2), 551-566; https://doi.org/10.3390/civileng4020032 - 10 May 2023

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Concrete in Structural Engineering for Sustainability)

► Show Figures

Figure 1

Open AccessHypothesis

Challenges in Determining the Scope of Rail Megaprojects: Responding to Ever-Increasing Infrastructure Demand

by

Koorosh Gharehbaghi

,

Kong Fah Tee

and

Kerry McManus

CivilEng 2023, 4(2), 538-550; https://doi.org/10.3390/civileng4020031 - 08 May 2023

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Feature Papers in CivilEng)

► Show Figures

Figure 1

Open AccessArticle

Feasibility Study on the Effect of FRP Shear Reinforcements on the Behaviour of FRP-Reinforced Concrete Deep Beams

by

Fawzi Latosh

,

Abobakr Al-Sakkaf

and

Ashutosh Bagchi

CivilEng 2023, 4(2), 522-537; https://doi.org/10.3390/civileng4020030 - 05 May 2023

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Feature Papers in CivilEng)

► Show Figures

Figure 1

Open AccessArticle

Numerical and Code-Based Investigation on the Impact of Corrosion on the Ultimate Compressive Strength of Steel Angle Members Using Thickness Reduction Method

by

Chamath Ravindu Senevirathna

,

Chaminda S. Bandara

and

Sudath C. Siriwardane

CivilEng 2023, 4(2), 506-521; https://doi.org/10.3390/civileng4020029 - 27 Apr 2023

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Feature Papers in CivilEng)

► Show Figures

Figure 1

Open AccessArticle

Numerical Modeling and Analysis of Strengthened Steel–Concrete Composite Beams in Sagging and Hogging Moment Regions

by

,

,

,

and

CivilEng 2023, 4(2), 483-505; https://doi.org/10.3390/civileng4020028 - 27 Apr 2023

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Feature Papers in CivilEng)

► Show Figures

Figure 1

Open AccessReview

Experimental Evaluation of Post-Earthquake Fire on Reinforced Concrete Structures—A Review

by

Vahid Khiali

and

Hugo Rodrigues

CivilEng 2023, 4(2), 469-482; https://doi.org/10.3390/civileng4020027 - 26 Apr 2023

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Connections in Concrete Volume 2)

► Show Figures

Figure 1

Open AccessArticle

Assessment of the Type of Paint on Performance of Rendering Mortars

by

Luis G. Baltazar

and

Antonio Morais

CivilEng 2023, 4(2), 454-468; https://doi.org/10.3390/civileng4020026 - 24 Apr 2023

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Topic Built Environment and Human Comfort)

► Show Figures

Figure 1

Open AccessReview

Eco-Friendly Geopolymer Composites Prepared from Agro-Industrial Wastes: A State-of-the-Art Review

by

,

,

,

,

George Uwadiegwu Alaneme

and

Qadir Bux alias Imran Latif

CivilEng 2023, 4(2), 433-453; https://doi.org/10.3390/civileng4020025 - 19 Apr 2023

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Feature Papers in CivilEng)

► Show Figures

Figure 1

Open AccessArticle

Investigation of Resonant Signal Timing Plans through Comprehensive Evaluation of Various Optimization Approaches

by

Nemanja Dobrota

,

Aleksandar Stevanovic

,

Yifei Yang

and

Suhaib Alshayeb

CivilEng 2023, 4(2), 416-432; https://doi.org/10.3390/civileng4020024 - 12 Apr 2023

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Section Urban, Economy, Management and Transportation Engineering)

► Show Figures

Figure 1

Open AccessReview

Recent Advances in Corrosion Assessment Models for Buried Transmission Pipelines

by

Xian-Kui Zhu

CivilEng 2023, 4(2), 391-415; https://doi.org/10.3390/civileng4020023 - 07 Apr 2023

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Feature Papers in CivilEng)

► Show Figures

Figure 1

Open AccessArticle

Features of Regulation Document Translation into a Machine-Readable Format within the Verification of Building Information Models

by

Elena Makisha

CivilEng 2023, 4(2), 373-390; https://doi.org/10.3390/civileng4020022 - 03 Apr 2023

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Feature Papers in CivilEng)

► Show Figures

Figure 1

Open AccessArticle

Post-Fire Mechanical Properties of Concrete Incorporating Waste EPS (Styrofoam) as Aggregate Replacement

by

,

,

,

and

CivilEng 2023, 4(2), 359-372; https://doi.org/10.3390/civileng4020021 - 27 Mar 2023

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Feature Papers in CivilEng)

► Show Figures

Figure 1

Open AccessArticle

Port-of-Entry Simulation Model for Potential Wait Time Reduction and Air Quality Improvement: A Case Study at the Gateway International Bridge in Brownsville, Texas, USA

by

,

,

,

and

CivilEng 2023, 4(1), 345-358; https://doi.org/10.3390/civileng4010020 - 20 Mar 2023

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Next Generation Infrastructure)

► Show Figures

Figure 1

Open AccessArticle

A Direct Tensile Strength Testing Method for Concrete from Existing Structures

by

Jonny Nilimaa

and

Rasoul Nilforoush

CivilEng 2023, 4(1), 333-344; https://doi.org/10.3390/civileng4010019 - 16 Mar 2023

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Feature Papers in CivilEng)

► Show Figures

Figure 1

Open AccessArticle

Site-Specific Response Spectra and Accelerograms on Bedrock and Soil Surface

by

,

,

and

CivilEng 2023, 4(1), 311-332; https://doi.org/10.3390/civileng4010018 - 16 Mar 2023

Cited by 2

Abstract

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 [...] Read more.

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 C_e sites and two example class D_e 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 B_e 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. Full article

(This article belongs to the Special Issue Site-Specific Seismic Design of Buildings)

► Show Figures

Figure 1

Open AccessArticle

Beam-Truss Models to Simulate the Axial-Flexural-Torsional Performance of RC U-Shaped Wall Buildings

by

Ryan Hoult

,

António A. Correia

and

João Pacheco de Almeida

CivilEng 2023, 4(1), 292-310; https://doi.org/10.3390/civileng4010017 - 13 Mar 2023

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Site-Specific Seismic Design of Buildings)

► Show Figures

Figure 1

Journal Description

CivilEng

Latest Articles

Journal Menu

Journal Browser

Highly Accessed Articles

Latest Books

E-Mail Alert

News

Topics

Conferences

Special Issues

Further Information

Guidelines

MDPI Initiatives

Follow MDPI