Infrastructures

13 pages, 875 KiB

Open AccessArticle

Delays in the Road Construction Projects from Risk Management Perspective

by Reza Mohajeri Borje Ghaleh, Towhid Pourrostam, Naser Mansour Sharifloo, Javad Majrouhi Sardroud and Ebrahim Safa

Infrastructures 2021, 6(9), 135; https://doi.org/10.3390/infrastructures6090135 - 20 Sep 2021

Cited by 10 | Viewed by 3470

Abstract

Delays in the execution stage of road construction projects are one of the significant challenges. The incapability of finishing projects according to schedule has attracted many researchers’ attention to this issue. This study has been formed to investigate delays in road construction projects [...] Read more.

Delays in the execution stage of road construction projects are one of the significant challenges. The incapability of finishing projects according to schedule has attracted many researchers’ attention to this issue. This study has been formed to investigate delays in road construction projects from a risk management perspective. In this study, risks have been identified by structured interviews with experts. Qualitative risk analysis by a survey of experts and quantitative risk analysis by analytical hierarchy process (AHP) technique have been performed. Research results show that financial and credit problems, lands’ funding, management problems, technical problems, and natural disasters have the highest risk among the main criteria. Among the subcriteria of the risk, incomplete funding with a weight of 0.188, gardens and land price with 0.114 are the most critical risk, and ground operations with 0.017, asphalt problems with 0.009, and accident insurance with a weight of 0.006 are the least essential risk. In the following, critical criteria analysis has been performed, and solutions to reduce or eliminate these delays in road construction projects are presented. Full article

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18 pages, 7247 KiB

Open AccessArticle

Deep Learning and YOLOv3 Systems for Automatic Traffic Data Measurement by Moving Car Observer Technique

by Marco Guerrieri and Giuseppe Parla

Infrastructures 2021, 6(9), 134; https://doi.org/10.3390/infrastructures6090134 - 18 Sep 2021

Cited by 12 | Viewed by 2945

Abstract

Macroscopic traffic flow variables estimation is of fundamental interest in the planning, designing and controlling of highway facilities. This article presents a novel automatic traffic data acquirement method, called MOM-DL, based on the moving observer method (MOM), deep learning and YOLOv3 algorithm. The [...] Read more.

Macroscopic traffic flow variables estimation is of fundamental interest in the planning, designing and controlling of highway facilities. This article presents a novel automatic traffic data acquirement method, called MOM-DL, based on the moving observer method (MOM), deep learning and YOLOv3 algorithm. The proposed method is able to automatically detect vehicles in a traffic stream and estimate the traffic variables flow q, space mean speed vs. and vehicle density k for highways in stationary and homogeneous traffic conditions. The first application of the MOM-DL technique concerns a segment of an Italian highway. In the experiments, a survey vehicle equipped with a camera has been used. Using deep learning and YOLOv3 the vehicles detection and the counting processes have been carried out for the analyzed highway segment. The traffic flow variables have been calculated by the Wardrop relationships. The first results demonstrate that the MOM and MOM-DL methods are in good agreement with each other despite some errors arising with MOM-DL during the vehicle detection step due to a variety of reasons. However, the values of macroscopic traffic variables estimated by means of the Drakes’ traffic flow model together with the proposed method (MOM-DL) are very close to those obtained by the traditional one (MOM), being the maximum percentage variation less than 3%. Full article

(This article belongs to the Special Issue Inspection, Assessment and Retrofit of Transport Infrastructure)

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13 pages, 242 KiB

Open AccessReview

Adopting International Learnings to Improve the Performance of New Zealand’s Infrastructure Supply Chain

by Jarrod Richards and Mostafa Seifan

Infrastructures 2021, 6(9), 133; https://doi.org/10.3390/infrastructures6090133 - 15 Sep 2021

Viewed by 1604

Abstract

Growing interest in the productivity of the infrastructure sector has increased due to cost and time overruns in major projects. In this regard, many developed countries have failed to implement a framework to ensure that project success is met through newly available technologies [...] Read more.

Growing interest in the productivity of the infrastructure sector has increased due to cost and time overruns in major projects. In this regard, many developed countries have failed to implement a framework to ensure that project success is met through newly available technologies and business initiatives to ensure the user is the most important beneficiary. This review paper provides a review of international research relating to the life cycle, firm-level operations, and collaborative business models of infrastructure projects. The review initially identified the importance that understanding key phases and procurement models has on the efficiency of a project’s life cycle. A key indicator of the likelihood of good performance across a supply chain lies with the ability to understand the efficiencies of the firm-level operations. The literature has noted that successful projects are able to perform well across an organizations end-to-end involvement and be able to share risks among mature organizations. This paper provides a review of how a collaborative business model can benefit a project lifecycle and firm-level operations. The global research currently has identified the need for a collaborative approach that reduces the risk within all organizations through common goals, effective end-to-end project systems and consideration of the entire project lifecycle. The paper provides a detailed review of international practices in an infrastructure supply chain that have the potential to address New Zealand’s infrastructure project failures. Full article

(This article belongs to the Special Issue Smart, Sustainable and Resilient Infrastructures)

20 pages, 13735 KiB

Open AccessArticle

Bridge Inspection and Defect Recognition with Using Impact Echo Data, Probability, and Naive Bayes Classifiers

by Faezeh Jafari and Sattar Dorafshan

Infrastructures 2021, 6(9), 132; https://doi.org/10.3390/infrastructures6090132 - 14 Sep 2021

Cited by 10 | Viewed by 2193

Abstract

Interpretation of IE data have been carried out by analyzing IE signals in frequency domain to determine the maximum frequency. However, the current peak frequency method can be inaccurate. The purpose of this research is to introduce features in IE signals that can [...] Read more.

Interpretation of IE data have been carried out by analyzing IE signals in frequency domain to determine the maximum frequency. However, the current peak frequency method can be inaccurate. The purpose of this research is to introduce features in IE signals that can be used for effective classification and interpretation for bridge deck evaluation through statistical analysis and Naive Bayes classifiers. The dataset contained IE data collected from eight slabs created at Advanced Sensing Technology FAST NDE laboratory (FHWA). A set of statistical features in time domain, normalized peak values, and length of preprocessed signals were used to classify the IE data, statistically. Then, Naive Bayes classifiers was employed to recognize defect area. Finally, the result of statistical classification was compared with frequency approach. The result shows that 19 and 21% of the IE signals collected from the defect area have multiple peaks, respectively. However, 85% of the IE signals collected from the sound set had only one peak. A probability classifier was used to find the relationship between the result of the frequency method and statistical analysis. The result shows that 10% of the IE signals were usable for estimating the thickness in the sound group. Full article

(This article belongs to the Special Issue Non-destructive Testing and Evaluation for Civil Infrastructures)

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29 pages, 17074 KiB

Open AccessArticle

Defining the Thermal Features of Sub-Surface Reinforcing Fibres in Non-Polluting Thermo–Acoustic Insulating Panels: A Numerical–Thermographic–Segmentation Approach

by Kaixin Liu, Stefano Perilli, Arsenii O. Chulkov, Yuan Yao, Mohammed Omar, Vladimir Vavilov, Yi Liu and Stefano Sfarra

Infrastructures 2021, 6(9), 131; https://doi.org/10.3390/infrastructures6090131 - 10 Sep 2021

Cited by 1 | Viewed by 1538

Abstract

Natural fibres present ozone-friendly solutions in the field of construction. The attenuation of the sound and heat losses is an important feature in such type of materials above all, when used in non-woven fabrics and fibre-reinforced composites. Hemp fibres show robust insulation performance; [...] Read more.

Natural fibres present ozone-friendly solutions in the field of construction. The attenuation of the sound and heat losses is an important feature in such type of materials above all, when used in non-woven fabrics and fibre-reinforced composites. Hemp fibres show robust insulation performance; this research work should be considered beneficial to the development of a non-destructive thermographic methodology, which can address the thermal barrier (typically applied on multi-layer panel) effects. The intent is to assess the integrity of the sub-surface reinforcing glass fibres; such integrity state will help confer the rigidity and the resistance to mechanical stresses. The testing proposed in this study can be further developed in a laboratory right after the manufacturing process of similar type of components. The testing needs preliminary numerical simulations to help guide the selection of the appropriate pre- and post-processing algorithms combined with or without segmentation operators. A set of numerical and experimental tests were performed through controlled thermal stimulation while recording the thermal responses. The study also highlights the advantages, disadvantages, and future development of the presented technique and methodologies. Full article

(This article belongs to the Special Issue Sustainability of Building Materials and Structures)

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19 pages, 4601 KiB

Open AccessArticle

Model Bridge Span Traversed by a Heavy Mass: Analysis and Experimental Verification

by Georgios I. Dadoulis and George D. Manolis

Infrastructures 2021, 6(9), 130; https://doi.org/10.3390/infrastructures6090130 - 10 Sep 2021

Cited by 4 | Viewed by 1536

Abstract

In this work, we investigate the transient response of a model bridge traversed by a heavy mass moving with constant velocity. Two response regimes are identified, namely forced vibrations followed by free vibrations as the moving mass goes past the far support of [...] Read more.

In this work, we investigate the transient response of a model bridge traversed by a heavy mass moving with constant velocity. Two response regimes are identified, namely forced vibrations followed by free vibrations as the moving mass goes past the far support of the simply supported span of the bridge. Despite this being a classical problem in structural dynamics, there is an implicit assumption in the literature that moving loads possess masses that are at least an order of magnitude smaller than the mass of the bridge span that they traverse. This alludes to interaction problems involving secondary systems, whose presence does not alter the basic characteristics of the primary system. In our case, the dynamic properties of the bridge span during the passage of a heavy mass change continuously over time, leading to an eigenvalue problem that is time dependent. During the free vibration regime, however, the bridge recovers the expected dynamic properties corresponding to its original configuration. Therefore, the aim here is the development of a mathematical model whose numerical solution is validated by comparison with experimental results recovered from an experiment involving a scaled bridge span traversed by a rolling mass. Following that, the target is to identify regions in the transient response of the bridge span that can be used for recovering the bridge’s dynamic properties and subsequently trace the development of structural damage. In closing, the present work has ramifications in the development of structural health monitoring systems applicable to critical civil engineering infrastructure, such as railway and highway bridges. Full article

(This article belongs to the Special Issue Damage Detection and Model Updating of Bridges Using Vibration Measurements)

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20 pages, 6400 KiB

Open AccessArticle

Rock Strain Prediction Using Deep Neural Network and Hybrid Models of ANFIS and Meta-Heuristic Optimization Algorithms

by T. Pradeep, Abidhan Bardhan, Avijit Burman and Pijush Samui

Infrastructures 2021, 6(9), 129; https://doi.org/10.3390/infrastructures6090129 - 07 Sep 2021

Cited by 20 | Viewed by 2278

Abstract

The majority of natural ground vibrations are caused by the release of strain energy accumulated in the rock strata. The strain reacts to the formation of crack patterns and rock stratum failure. Rock strain prediction is one of the significant works for the [...] Read more.

The majority of natural ground vibrations are caused by the release of strain energy accumulated in the rock strata. The strain reacts to the formation of crack patterns and rock stratum failure. Rock strain prediction is one of the significant works for the assessment of the failure of rock material. The purpose of this paper is to investigate the development of a new strain prediction approach in rock samples utilizing deep neural network (DNN) and hybrid ANFIS (adaptive neuro-fuzzy inference system) models. Four optimization algorithms, namely particle swarm optimization (PSO), Fireflies algorithm (FF), genetic algorithm (GA), and grey wolf optimizer (GWO), were used to optimize the learning parameters of ANFIS and ANFIS-PSO, ANFIS-FF, ANFIS-GA, and ANFIS-GWO were constructed. For this purpose, the necessary datasets were obtained from an experimental setup of an unconfined compression test of rocks in lateral and longitudinal directions. Various statistical parameters were used to investigate the accuracy of the proposed prediction models. In addition, rank analysis was performed to select the most robust model for accurate rock sample prediction. Based on the experimental results, the constructed DNN is very potential to be a new alternative to assist engineers to estimate the rock strain in the design phase of many engineering projects. Full article

(This article belongs to the Special Issue Artificial Intelligence in Infrastructure Geotechnics)

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22 pages, 5248 KiB

Open AccessArticle

Fiber Reinforced Polymer Culvert Bridges—A Feasibility Study from Structural and LCC Points of View

by Reza Haghani, Jincheng Yang, Marte Gutierrez, Christopher D. Eamon and Jeffery Volz

Infrastructures 2021, 6(9), 128; https://doi.org/10.3390/infrastructures6090128 - 07 Sep 2021

Cited by 2 | Viewed by 4854

Abstract

Soil–steel composite bridges (SSCB) have become increasingly popular for short-span bridges as an alternative to concrete slab bridges mainly due to their low initial cost, rapid manufacture, simplified construction, and geometrical adaptability. SSCBs have a variety of applications and can be used over [...] Read more.

Soil–steel composite bridges (SSCB) have become increasingly popular for short-span bridges as an alternative to concrete slab bridges mainly due to their low initial cost, rapid manufacture, simplified construction, and geometrical adaptability. SSCBs have a variety of applications and can be used over waterways or roadways. While conventional bridges tend to lose their load-carrying capacity due to degradation, SSCBs gain strength because of backfill soil consolidation. However, the load carrying capacity and integrity of such structures highly depends on the condition and load-carrying capacity of the steel arch element. A major drawback of SSCBs, especially those located on waterways or with poor drainage, is corrosion and subsequent loss of cross-sectional capacity. Unfortunately, the inspection of such bridges is not straightforward and any damage/collapse will be very costly to repair/replace. Fiber reinforced polymer (FRP) composites offer an attractive alternative to replace the steel in these types of bridges. FRP composites have significantly improved durability characteristics compared to steel, which will reduce maintenance costs and improve life-cycle costs (LLCs). This paper presents a new concept to use glass FRP as a construction material to construct soil–FRP composite bridges (SFCB). Various aspects of design and manufacturing are presented along with results and conclusions from a case study involving alternative bridge designs in steel and FRP composites. Full article

(This article belongs to the Special Issue Inspection, Assessment and Retrofit of Transport Infrastructure)

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25 pages, 31244 KiB

Open AccessArticle

Effects of Hydropower Dam Operation on Riverbank Stability

by Soonkie Nam, Marte Gutierrez, Panayiotis Diplas and John Petrie

Infrastructures 2021, 6(9), 127; https://doi.org/10.3390/infrastructures6090127 - 03 Sep 2021

Cited by 1 | Viewed by 2035

Abstract

The increasing number of extreme climate events has impacted the operation of reservoirs, resulting in drastic changes in flow releases from reservoirs. Consequently, downstream riverbanks have experienced more rapid and frequent changes of the river water surface elevation (WSE). These changes in the [...] Read more.

The increasing number of extreme climate events has impacted the operation of reservoirs, resulting in drastic changes in flow releases from reservoirs. Consequently, downstream riverbanks have experienced more rapid and frequent changes of the river water surface elevation (WSE). These changes in the WSE affect pore water pressures in riverbanks, directly influencing slope stability. This study presents an analysis of seepage and slope stability for riverbanks under the influence of steady-state, drawdown, and peaking operations of the Roanoke Rapids Hydropower dam on the lower Roanoke River, North Carolina, USA. Although the riverbanks were found to be stable under all the discharge conditions considered, which indicates that normal operations of the reservoir have no adverse effects on riverbank stability, the factor of safety decreases as the WSE decreases. When the role of fluvial erosion is considered, riverbank stability is found to reduce. Drawdown and fluctuation also decrease the safety factor, though the rate of the decrease depends more on the hydraulic conductivity of the soils rather than the discharge pattern. Full article

(This article belongs to the Special Issue Urban Geotechnical Engineering)

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17 pages, 10506 KiB

Open AccessArticle

Assessment on Bonding Potentials of Trackless Tack under a Thin Overlay

by Ah Young Seo, Maryam S. Sakhaeifar and Bryan T. Wilson

Infrastructures 2021, 6(9), 126; https://doi.org/10.3390/infrastructures6090126 - 03 Sep 2021

Cited by 2 | Viewed by 1729

Abstract

Trackless tacks are used to minimize the loss of tack materials caused by adherence to moving tires. During the last two decades, the paving industry and highway agencies have had an increasing interest in the use of trackless tacks to ensure an adequate [...] Read more.

Trackless tacks are used to minimize the loss of tack materials caused by adherence to moving tires. During the last two decades, the paving industry and highway agencies have had an increasing interest in the use of trackless tacks to ensure an adequate bond between the overlay and the existing pavement. Therefore, the need for more studies on the bonding characteristics of various trackless tacks is growing. The purpose of this study is to measure the bonding potential of trackless tacks and identify several variables that affect the shear resistance in terms of bonding strength and energy using statistical analysis. The improvement of interlayer shear resistance by tack treatment is different depending on the tack and surface types. Higher tack reactivation temperatures increase the interlayer shear resistance. Compaction effort is considered to have only a marginal effect on bond performance. Tack and surface types play a more critical role in determining the shear bond strength than residual tack rate in the field experiment. Full article

(This article belongs to the Special Issue Pavement Sustainability)

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20 pages, 22827 KiB

Open AccessArticle

Performance of Polymer Cementitious Coatings for High-Voltage Electrical Infrastructure

by Bowen Xu, Hui Li, Dan V. Bompa, Ahmed Y. Elghazouli and Jiangbo Chen

Infrastructures 2021, 6(9), 125; https://doi.org/10.3390/infrastructures6090125 - 02 Sep 2021

Cited by 2 | Viewed by 2557

Abstract

This paper investigates the electrical, thermal and mechanical properties as well as the environmental performance of polymer cementitious composites (PCCs) as sustainable coating materials for underground power cables and as high-voltage insulators. Particular focus is placed on the optimised mix design and the [...] Read more.

This paper investigates the electrical, thermal and mechanical properties as well as the environmental performance of polymer cementitious composites (PCCs) as sustainable coating materials for underground power cables and as high-voltage insulators. Particular focus is placed on the optimised mix design and the effect of the manufacturing method on the performance of PCCs, incorporating liquid styrene and acrylic (SA) monomers, wollastonite and muscovite. Microstructural investigations, together with results from strength tests, indicate that the manufacturing method is a key performance parameter. Experimental results show that PCC mixes containing 25% SA emulsion, 12.5% wollastonite and no muscovite provide the most favourable dielectric properties from the mixes investigated. The PCC material has a dielectric strength up to 16.5 kV/mm and a dielectric loss factor lower than 0.12. Additional experiments also show that PCC has good thermal stability and thermal conductivity. The mechanical strength tests indicate that PCC specimens possess reliable strengths which are applicable in structural design. Environmental assessments also show that PCCs possess significantly lower embodied energy and embodied carbon than conventional plastic insulating materials. Full article

(This article belongs to the Special Issue Reusing, Recycling and Repurposing Infrastructure: Components and Construction Materials)

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24 pages, 4719 KiB

Open AccessArticle

Uncertainty in Building Inspection and Diagnosis: A Probabilistic Model Quantification

by Clara Pereira, Ana Silva, Cláudia Ferreira, Jorge de Brito, Inês Flores-Colen and José D. Silvestre

Infrastructures 2021, 6(9), 124; https://doi.org/10.3390/infrastructures6090124 - 01 Sep 2021

Cited by 8 | Viewed by 2206

Abstract

In the field of building inspection and diagnosis, uncertainty is common and surveyors are aware of it, although it is not easily measured. This research proposes a model to quantify uncertainty based on the inspection of rendered façades. A Bayesian network is developed, [...] Read more.

In the field of building inspection and diagnosis, uncertainty is common and surveyors are aware of it, although it is not easily measured. This research proposes a model to quantify uncertainty based on the inspection of rendered façades. A Bayesian network is developed, considering three levels of variables: characteristics of the building, façade and exposure conditions; causes of defects; and defects. To compute conditional probabilities, the results of an inspection campaign from the literature are used. Then, the proposed model is validated and verified using inspection results from another sample, the combination of a strength-of-influence diagram and sensitivity analysis and the application of the model to a case study. Results show that the probabilities computed by the model are a reasonable representation of the hesitancy in decision making during the diagnosis process based only on visual observation. For instance, design and execution errors show lower probabilities due to not being verifiable a posteriori without detailed documentation. The proposed model may be extended and replicated for other building materials in the future, as it may be a useful tool to improve the perception of uncertainty in a key stage of building maintenance or rehabilitation. Full article

(This article belongs to the Special Issue Durability and Degradability of Construction Materials)

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Graphical abstract

11 pages, 5992 KiB

Open AccessArticle

The Adhesion and Diffusion of Saturate, Asphaltene, Resin and Aromatic (SARA) Molecules on Oxygenated and Hydrogenated Carbon Nanotubes (CNTs)

by Mehdi Shishehbor, Hadi S. Esmaeeli and M. Reza Pouranian

Infrastructures 2021, 6(9), 123; https://doi.org/10.3390/infrastructures6090123 - 01 Sep 2021

Cited by 1 | Viewed by 2026

Abstract

The interfacial adhesion between asphalt binder and carbon nanotubes (CNTs) depends on many nanoscopic properties such as diffusion of SARA molecules on CNTs surface. Functionalization of CNTs with Oxygens (O=CNTs), hydroxyl groups (HO–CNTs), and hydrogens (H–CNTs) has been an effective way to modify [...] Read more.

The interfacial adhesion between asphalt binder and carbon nanotubes (CNTs) depends on many nanoscopic properties such as diffusion of SARA molecules on CNTs surface. Functionalization of CNTs with Oxygens (O=CNTs), hydroxyl groups (HO–CNTs), and hydrogens (H–CNTs) has been an effective way to modify the surface properties of CNTs and ultimately the macroscopic properties of the CNT-composites. This paper presents the effect of different dosages of oxygenated and hydrogenated CNTs on the adhesion and diffusion of SARA molecules on CNTs’ surfaces. First, reactive molecular dynamics simulation is used to oxygenate and hydrogenate CNTs up to a certain dosage. Next, it is employed to model the interaction and diffusion of SARA molecules with the functionalized CNTs. We employ the steer molecular dynamic (SMD) and Einstein formula to calculate the adhesion and diffusion properties. The results demonstrate that hydrogenation has little effect on the adhesion energy, while oxygenation can increase adhesion energy up to 100% for 25% dosage. The diffusion coefficient dramatically drops for both oxygenated and hydrogenated CNTs, with lower values for the latter. We observe that for hydrogenated and oxygenated CNTs at different dosages, asphaltene, resin, aromatic, and saturate molecules have the highest to lowest values, respectively. Full article

(This article belongs to the Section Infrastructures Materials and Constructions)

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12 pages, 3930 KiB

Open AccessArticle

Assessment of Traffic Sign Comprehension Levels among Drivers in the Emirate of Abu Dhabi, UAE

by Taleb M. Al-Rousan and Abdullahi A. Umar

Infrastructures 2021, 6(9), 122; https://doi.org/10.3390/infrastructures6090122 - 31 Aug 2021

Cited by 5 | Viewed by 4439

Abstract

Road traffic signs are part of the road infrastructure components meant to ensure the safe use of roads by motorists and pedestrians alike. A good knowledge and comprehension of road signs helps ensure smooth flow of traffic, improves safety for other motorists and [...] Read more.

Road traffic signs are part of the road infrastructure components meant to ensure the safe use of roads by motorists and pedestrians alike. A good knowledge and comprehension of road signs helps ensure smooth flow of traffic, improves safety for other motorists and provides drivers with good reaction time to comply with the message dictated by the signs. Abu Dhabi, being the capital of the UAE, brings together people from all over the world for work, business or tourism. Abu Dhabi has quality roads and traffic signage together with an efficient police force that enforces adherence to traffic rules. Despite all these and the reduced fatalities in absolute terms, traffic violations have been increasing exponentially, resulting in five million traffic fines in 2019 for a population of about 2.9 million inhabitants. This study sought to assess motorists’ comprehension of the various traffic signs used across the UAE. The results of the survey (N = 200) revealed that the drivers were able to correctly identify 77% of the road signs in the survey. It was also found that the respondents failed to correctly identify traffic signs within the specific category referred to as “advance warning signs”. Respondents’ education, nationality, gender, and marital status did not have any statistically significant effects on the results compared to earlier studies. It is recommended that more attention be focused on driver education and training. Full article

(This article belongs to the Special Issue Transport Systems: Safety Modeling, Visions and Strategies)

15 pages, 7082 KiB

Open AccessArticle

Construction and Performance Monitoring of Innovative Ultra-High-Performance Concrete Bridge

by Haena Kim, Byungkyu Moon, Xinyu Hu, Hosin (David) Lee, Gum-Sung Ryu, Kyung-Taek Koh, Changbin Joh, Byung-Suk Kim and Brian Keierleber

Infrastructures 2021, 6(9), 121; https://doi.org/10.3390/infrastructures6090121 - 30 Aug 2021

Cited by 8 | Viewed by 2622

Abstract

The application of Ultra-High-Performance Concrete (UHPC) materials in rehabilitating bridges and constructing primary bridge components is increasing rapidly across the world because of their superior strength and durability characteristics when compared to regular concretes. However, there have been few new bridges constructed using [...] Read more.

The application of Ultra-High-Performance Concrete (UHPC) materials in rehabilitating bridges and constructing primary bridge components is increasing rapidly across the world because of their superior strength and durability characteristics when compared to regular concretes. However, there have been few new bridges constructed using UHPC materials with regular formworks, ready-mix trucks, and construction equipment. This paper presents a comprehensive report encompassing the design, construction, and performance monitoring of a new bridge constructed in Iowa using a unique UHPC technology that includes steel fibers of two different lengths embedded in the concrete. By using optimized lengths of steel fibers, both the tensile strength and the toughness were increased. The UHPC material was produced with local cement and aggregates in the US using typical ready-mix concrete equipment. This paper discusses the experience gained from the design and construction process including mix design, batching, delivery of steel fibers to the ready-mix concrete batch unit, and post-tensioning of precast slabs at the jobsite. For four years after construction, the joints of the bridge decks were monitored using strain sensors mounted on both sides of the deck joints. The strain values were quite similar between the two sides of each joint, indicating a good load transfer between precast bridge girders. A bridge was successfully constructed using a unique UHPC technology incorporating two different lengths of steel fibers and utilizing local cement and aggregates and a ready-mix truck, and has been performing satisfactorily with a good load transfer across post-tensioned precast girder joints. Full article

(This article belongs to the Special Issue Infrastructures for Smart Cities)

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17 pages, 6331 KiB

Open AccessArticle

Numerical Evaluation for Roads Considering the Addition of Geogrids in Karst Geohazards Zones

by Alain Leonel Conrado-Palafox, Luisa Nicte Equihua-Anguiano and Victor Alfonso Hernández-Hernández

Infrastructures 2021, 6(9), 120; https://doi.org/10.3390/infrastructures6090120 - 30 Aug 2021

Cited by 1 | Viewed by 2227

Abstract

Design of road infrastructure in karst terrain is a challenge for any geotechnical condition caused by the weathering of the subsoil. Previous investigations pointed out the efficiency of the roads with geogrids, however there are few studies analyzing road reinforced under karst geohazards. [...] Read more.

Design of road infrastructure in karst terrain is a challenge for any geotechnical condition caused by the weathering of the subsoil. Previous investigations pointed out the efficiency of the roads with geogrids, however there are few studies analyzing road reinforced under karst geohazards. This paper presents a numerical study of the geogrid additions in a typical Mexican road and considering 19 cavities in the subsoil due to failures of the roads in these terrains. The rocks and the soil were simulated by Hoek–Brown and Mohr–Coulomb constitutive models, considering specific characteristics of karstic materials. Hence, it was carried out in different two-dimension finite element models to analyze the geogrid behavior and its benefits. First, the geogrid position was varied inside of the road structure and applying a heavy truck load in its surface and finally, underground cavities were sequentially opened in the numerical model. It was established the best combination of the road-geogrid structure construction and the influence when cavities are developed underground analyzing the stress paths in the medium. From this study, it is found, that when the geogrid layer is embedded between bedrock and subgrade, the failure is mitigated, observing an increase in the factor of safety even with 19 voids presence in the model. Concluding that the geogrid is an adequate solution of reinforcement of roads. Full article

(This article belongs to the Special Issue Research and Developments in Pavements)

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24 pages, 3627 KiB

Open AccessArticle

The Use of ICT-Based Applications to Support the Implementation of Smart Cities during the COVID-19 Pandemic in Indonesia

by Rini Rachmawati, Ayu Dianita Sari, Haddad Al Rasyid Sukawan, I Made Arya Widhyastana and Rizki Adriadi Ghiffari

Infrastructures 2021, 6(9), 119; https://doi.org/10.3390/infrastructures6090119 - 26 Aug 2021

Cited by 19 | Viewed by 5064

Abstract

The COVID-19 pandemic has resulted in compulsion and encouragement of actions that have enabled changes to occur globally that have then been adapted to current conditions. For their highly dense populations, it is difficult to control the spread of the virus in cities. [...] Read more.

The COVID-19 pandemic has resulted in compulsion and encouragement of actions that have enabled changes to occur globally that have then been adapted to current conditions. For their highly dense populations, it is difficult to control the spread of the virus in cities. As a result, activities that draw large crowds together so that people can access public services are inevitable. Several cities that have been declared as smart cities in Indonesia have made a breakthrough by making use of information and communication technology (ICT)-based applications. This can be of great help for societies during pandemics. ICT has been able to help citizens perform various activities from home with the help of applications. This study aims to identify various applications that support the implementation of the concept of a smart city. This applies particularly to those applications that are based on ICT that can tackle the unique conditions of the COVID-19 pandemic and make recommendations regarding future developments. The data collected for this study were analyzed using secondary sources obtained from various clusters of literature, the internet, and social media. In addition, primary data was gathered from discussion forums. This paper employs a qualitative approach with qualitative descriptive data analysis techniques and hierarchical cluster analysis. Qualitative descriptive analysis was utilized to explore the conditions of smart cities, the regional conditions of the pandemic, and smart city applications more generally. The results show that during the COVID-19 pandemic, cities and regions, including the 100 smart cities in Indonesia, have developed many innovative solutions through ICT-based applications that can help people maintain an active social life and access public services. In the future, when everything is allegedly back to normal, cities need to implement the use of various ICT-based applications to increase efficiency in their planning and management. Therefore, it has become increasingly necessary to improve people’s digital literacy and to develop a type of ICT infrastructure that enables more people to access the internet. Full article

(This article belongs to the Section Smart Infrastructures)

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14 pages, 3992 KiB

Open AccessArticle

The Main Impacts of Infrastructure Works on Public Roads

by Eduardo A. N. e Santos, Clézio T. de S. Dutra, Christine K. Chinelli, Ahmed W. A. Hammad, Assed N. Haddad and Carlos A. P. Soares

Infrastructures 2021, 6(9), 118; https://doi.org/10.3390/infrastructures6090118 - 24 Aug 2021

Cited by 4 | Viewed by 2956

Abstract

Infrastructure implementation and renovation in cities require work on public roads that impact the daily lives of road users and local population and commerce. Although the study of the impacts of infrastructure works in the researched literature has received various approaches, there is [...] Read more.

Infrastructure implementation and renovation in cities require work on public roads that impact the daily lives of road users and local population and commerce. Although the study of the impacts of infrastructure works in the researched literature has received various approaches, there is still a shortage of studies that identify the impacts of the implementation of infrastructure on public roads and the importance of each one. This study collaborates with this theme by researching the main impacts caused by infrastructure works on public roads based on extensive and detailed bibliographic research and based on a survey carried out toward residents of the areas impacted by these works, road users, and Brazilian professionals with experience in the concerned field. The results showed that fourteen impacts identified in the literature were considered important by survey respondents, of which seven were considered the most important. Full article

(This article belongs to the Special Issue Smart, Sustainable and Resilient Infrastructures)

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Infrastructures, Volume 6, Issue 9 (September 2021) – 18 articles

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