Infrastructures最新文献

{"title":"Public–Private Partnerships: A Fresh Risk-Based Approach to Water Sector Projects","authors":"S. Lima, A. Brochado, R. Marques","doi":"10.3390/infrastructures8060102","DOIUrl":"https://doi.org/10.3390/infrastructures8060102","url":null,"abstract":"This study focused on the unbalanced relationships that can arise in current public–private partnership (PPP) risk management frameworks, especially in developing countries’ water sectors. Different stakeholders’ perceptions of risk management were examined by analyzing 15 interviews in Portugal and Mozambique. The hybrid method included semantic, descriptive statistic, content, and narrative analyses. To achieve the research objectives, the semi-structured interview transcripts were processed using quantitative and qualitative techniques to collate relevant actors’ opinions of risk management in PPP water projects. Five risk categories were identified. The interviewed experts ranked the financial risk category as the most crucial, followed by infrastructure, commercial, technical and operational, and context risks. However, when the transcripts were evaluated from a risk factor perspective, the context risk category unexpectedly jumped to first place. Twenty-five high-impact risk factors were isolated in the semi-structured interview contents. The top five most critical risk factors were political interference, no performance measurement baselines, an unfavorable private investment climate, nonpayment of bills, and water assets uncertain condition. The results comprise a fresh contribution to the existing knowledge about experts’ perceptions of PPP contract risks, including that prior research and specialists categorize financial risks as the most important. The findings further reveal that experts consider managing context risks to be the key factor in PPPs success in developing countries, as well as highlighting the need to explore these risks more fully in emerging economies’ water sectors. In addition, a complete risk management cycle is proposed based on the interviewed professionals’ opinions, in which risk assessment and risk treatment or mitigation measures are dealt with simultaneously.","PeriodicalId":13601,"journal":{"name":"Infrastructures","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41726144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prediction of Fatalities at Northern Indian Railways’ Road–Rail Level Crossings Using Machine Learning Algorithms","authors":"Anil Kumar Chhotu, S. Suman","doi":"10.3390/infrastructures8060101","DOIUrl":"https://doi.org/10.3390/infrastructures8060101","url":null,"abstract":"Highway railway level crossings, also widely recognized as HRLCs, present a significant threat to the safety of everyone who uses a roadway, including pedestrians who are attempting to cross an HRLC. More studies with new, proposed solutions are needed due to the global rise in HRLC accidents. Research is required to comprehend driver behaviours, user perceptions, and potential conflicts at level crossings, as well as for the accomplishment of preventative measures. The purpose of this study is to conduct an in-depth investigation of the HRLCs involved in accidents that are located in the northern zone of the Indian railway system. The accident information maintained by the distinct divisional and zonal offices in the northern railways of India is used for this study. The accident data revealed that at least 225 crossings experienced at least one incident between 2006 and 2021. In this study, the logistic regression and multilayer perception (MLP) methods are used to develop an accident prediction model, with the assistance of various factors from the incidents at HRLCs. Both the models were compared with each other, and it was discovered that MLP supplied the best results for accident predictions compared to the logistic regression method. According to the sensitivity analysis, the relative importance of train speed is the most important, and weekday traffic is the least important.","PeriodicalId":13601,"journal":{"name":"Infrastructures","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46141732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental Tests and Numerical Analyses for the Dynamic Characterization of a Steel and Wooden Cable-Stayed Footbridge","authors":"V. Nicoletti, Simone Quarchioni, Luca Tentella, Riccardo Martini, F. Gara","doi":"10.3390/infrastructures8060100","DOIUrl":"https://doi.org/10.3390/infrastructures8060100","url":null,"abstract":"Vibrations are an issue of increasing importance in current footbridge design practice. More sophisticated footbridges with increasing spans and more effective construction materials result in lightweight structures and a high ratio of live load to dead load. As a result of this trend, many footbridges have become more susceptible to vibrations when subjected to dynamic loads. The most common dynamic loads on footbridges, other than wind loading, are pedestrian-induced footfall forces due to the movement of people. This paper concerns the experimental and numerical dynamic characterization of a newly built steel and wooden cable-stayed footbridge. The footbridge was dynamically tested in situ under ambient vibration, and the results allowed the real dynamic behavior of the footbridge to be captured. The dynamic response under pedestrian dynamic loads was also investigated and compared with the limitations provided by the main international codes and guidelines for footbridge serviceability assessment. A numerical model of the footbridge was also developed and updated based on the experimental outcomes. Then, the calibrated model was used to numerically assess the footbridge’s serviceability following the guideline prescriptions for pedestrian load simulation, and the design accuracy was also validated. This paper aims to increase the state-of-the-art knowledge about footbridge dynamic testing so as to support the design of new and futuristic structures as well as prove the effectiveness of using the requirements of codes and guidelines for footbridge serviceability assessment by adopting a calibrated numerical model.","PeriodicalId":13601,"journal":{"name":"Infrastructures","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42541927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geopolymers: The Green Alternative to Traditional Materials for Engineering Applications","authors":"Zahraa Jwaida, A. Dulaimi, Nuha S. Mashaan, Md Azree Othuman Mydin","doi":"10.3390/infrastructures8060098","DOIUrl":"https://doi.org/10.3390/infrastructures8060098","url":null,"abstract":"Researchers have been driven to investigate sustainable alternatives to cement production, such as geopolymers, due to the impact of global warming and climate change resulting from greenhouse gas emissions. Currently, they are exploring different methods and waste materials to enhance the mechanical and physical properties of geopolymer and expand its application range. This review paper offers a thorough analysis of the utilization of various waste materials in geopolymer manufacturing and shows the creative contribution of this research to the development of environmentally friendly cement substitutes. The article covers the properties, durability, and practical applications of geopolymer composites made from various waste binders. It includes a microstructure and chemical analysis. The research findings indicate that geopolymers are an effective cementitious binder substitute for cement in various applications. Additionally, the ecological and carbon footprint analysis highlights the sustainability of geopolymers compared to cement.","PeriodicalId":13601,"journal":{"name":"Infrastructures","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47431912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of Liquefaction Hazard and Mapping Based on Standard Penetration Tests in the Long Beach and Tuzla Regions of Cyprus","authors":"Onur Selcukhan, A. Ekinci","doi":"10.3390/infrastructures8060099","DOIUrl":"https://doi.org/10.3390/infrastructures8060099","url":null,"abstract":"Cyprus is the third largest and populated island in the Mediterranean Sea, and is still rapidly expanding. Significant infrastructures, such as hotels, educational institutions, and large residential complexes, are being built. Historically, 15 destructive earthquakes were reported on Cyprus from 1896 to 2019 that caused structural damages and casualties. In this study, the liquefaction potential of Tuzla and Long Beach on the east coast of Cyprus is estimated using the standard penetration test (SPT) data from more than 200 boreholes at different locations at the sites. The overall results are presented in a liquefaction potential index obtained from the factor of safety (F.S.) coefficient. Both study areas are susceptible to liquefaction. Thus, liquefaction potential maps are prepared to identify hazards in Tuzla and Long Beach. Additionally, the average factor of the safety line was introduced for both sites to create a correlation between the liquefaction area and F.S. values of every borehole. The adopted approach precisely provides the liquefiable regions when compared with historical evidence, CPT measurements, surface geology aspects, and geospatial data. Additionally, the results prove that the liquefaction potential must be considered during the design stage of new infrastructure in these areas.","PeriodicalId":13601,"journal":{"name":"Infrastructures","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48263611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance Comparison of 45° and 90° Herringboned Permeable Interlocking Concrete Pavement","authors":"Ali Shubbar, Mohammed Salah Nasr, Abdullah Kadhim, Tameem Mohammed Hashim, Monower Sadique","doi":"10.3390/infrastructures8050097","DOIUrl":"https://doi.org/10.3390/infrastructures8050097","url":null,"abstract":"Pavement deterioration is mainly caused by high traffic loading and by increased levels of runoff water resulting from storms, floods, or other reasons. Consequently, this issue can be efficiently solved by employing permeable pavement, such as permeable interlocking concrete pavement (PICP) to control water runoff and endure increased traffic loads. This study investigates the performance of PICP, in both 45° and 90° herringboned surface patterns, in terms of the infiltration of volumes of water, runoff water volumes, and the ability of pavement to withstand static loading. All the related tests in this study were implemented using a lab apparatus that was fabricated as a simulator for rainfall. Various conditions were adopted during the performance tests, including the application of longitudinal slopes (0, 2.5, 5, and 7.5%), side slopes (0, 2.5, and 5%), and different rainfall intensities (25, 50, 75, and 100 L/min). The results indicated that at high rainfall intensities (75 and 100 L/min), PICP with the 45° herringboned surface pattern had the highest volume of infiltrated water and the lowest runoff water at all the adopted longitudinal and side slopes. In addition, PICP with the 45° herringboned surface pattern showed higher resistance to deflection under a static loading test than the 90° herringboned pattern under the same conditions. Therefore, PICP with a 45° herringboned surface pattern showed supremacy in terms of runoff reduction and load resistance in comparison to PICP with a 90° herringboned pattern. Even though there are differences between the two types of PICP, they are both strongly recommended as alternatives to regular pavement.","PeriodicalId":13601,"journal":{"name":"Infrastructures","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135380434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Free Shrinkage Strains of Box Girders with Concrete Overlays","authors":"M.G. Parmiani, L. Orta","doi":"10.3390/infrastructures8050096","DOIUrl":"https://doi.org/10.3390/infrastructures8050096","url":null,"abstract":"The aging of reinforced concrete structures is one of the biggest concerns in civil engineering today since billions of dollars are spent annually on deck repairs and replacements. This study focuses on the rehabilitation of reinforced concrete box girders used in bridge construction. Bridge rehabilitation with a new concrete overlay possesses many challenges that involve cracking and debonding of the overlay caused by the restraining effect of the substrate. This effect leads to the development of tension stresses in the overlay, compression stresses in the substrate, and shear stresses at the interface. In order to mitigate this type of cracking and to ensure a desirable monolithic structural behavior of the rehabilitated bridge, a long-term assessment of the free shrinkage strains acting in the overlay is necessary. This study conducts a two-dimension finite element analysis of a reinforced concrete box girder bridge to evaluate humidity and free shrinkage strain profiles at different times. The humidity gradient between the overlay and the substrate generates differential volume changes between substrate and overlay. The substrate deformations are negligible, while the overlay is subjected to high shrinkage; 78% of the ultimate shrinkage strain is reached after 3 years, indicating a high susceptibility to cracking.","PeriodicalId":13601,"journal":{"name":"Infrastructures","volume":"1 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41444051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Using Construction and Demolition Waste Materials to Develop Chip Seals for Pavements","authors":"M. Shamsaei, A. Carter, M. Vaillancourt","doi":"10.3390/infrastructures8050095","DOIUrl":"https://doi.org/10.3390/infrastructures8050095","url":null,"abstract":"Construction and demolition waste (CDW) materials account for a considerable part of waste materials throughout the world. As these materials are not usually recycled, reusing them in construction projects is of major significance. In this study, recycled concrete, bricks, and glass were used as 100% aggregates of chip seal, which is a corrective or preventive pavement maintenance method. A cationic rapid setting (CRS-2) bitumen emulsion was also used to prepare the chip seal. Different tests, including the sand patch test, sweep test, British pendulum tester (BPT), interface bond, and Vialit test, were conducted. The results of these tests revealed that all these materials had sufficient aggregate embedment for vehicle speeds of more than 70 km/h, and the number of chips was less than 10%, indicating their good performance. All developed chip seals ranked as high skid resistance pavement at ambient temperature. The chip seals developed with concrete and glass showed the best adhesion with an asphalt pavement surface and an aggregate–bitumen adhesion at very cold and ambient temperatures due to the fact of their chemical compositions. Overall, using concrete aggregates to develop chip seals under different traffic loads is recommended. Finally, these findings can provide a novel approach for recycling CDW materials with low costs.","PeriodicalId":13601,"journal":{"name":"Infrastructures","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49205482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"SAR Interferometry Data Exploitation for Infrastructure Monitoring Using GIS Application","authors":"F. Orellana, P. J. .. D'Aranno, Silvia Scifoni, M. Marsella","doi":"10.3390/infrastructures8050094","DOIUrl":"https://doi.org/10.3390/infrastructures8050094","url":null,"abstract":"Monitoring structural stability in urban areas and infrastructure networks is emerging as one of the dominant socio-economic issues for population security. The problem is accentuated by the age of the infrastructure because of increasing risks due to material deterioration and loss of load capacity. In this case, SAR satellite data are crucial to identify and assess the deteriorating conditions of civil infrastructures. The large amount of data available from SAR satellite sensors leads to the exploitation and development of new GIS-based procedures for rapid responses and decision making. In recent decades, the DInSAR technique has been used efficiently for the monitoring of structures, providing measurement points located on structures with millimeter precision. Our study has analyzed the behavior of structures in settlements, attempting to discuss the interactions of soil and structures, and examining the behavior of different types of structures, such as roads and buildings. The method used is based on long-term SAR interferometry data and a semi-automatic procedure to measure the displacement (mm/year) of structures, through a GIS-based application performed in the “Implemented MOnitoring DIsplacement” I.MODI platform. The analysis provides extensive information on long-term spatial and temporal continuity of up to 25 years of record, using satellite SAR multi-sensors from ERS, Envisat, and COSMO-SkyMed. The interpretation uses time series spatial analysis, supported by orthophotos, and layers of the DBTR (regional topographic database), Digital Surface model (DSM), and hydrogeological map to show anomalous areas with a high displacement rate and to observe the correlation of settlements in the sediments. With the satellite information and Geographic Information System (GIS), we were able to observe relevant parameters, such as the velocity of advance in the direction of the slope (deformation profiles), the cumulative displacement, and the trend changes in structures. The results illustrate an innovative procedure that allows the management of DInSAR data to facilitate the effective management of structures in which a monitoring protocol was developed at different spatial scales, integrating the information into a GIS.","PeriodicalId":13601,"journal":{"name":"Infrastructures","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44428814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Visual Behaviour of the Cyclist: Comparison between Simulated and Real Scenarios","authors":"E. Acerra, Murad M. Shoman, H. Imine, Claudia Brasile, C. Lantieri, V. Vignali","doi":"10.3390/infrastructures8050092","DOIUrl":"https://doi.org/10.3390/infrastructures8050092","url":null,"abstract":"Cyclists are one of the main categories of road users particularly exposed to accident risk. The increasing use of this ecological means of transport requires a specific assessment of cyclist safety in terms of traffic flow and human factors. In this study, a particular visual tracking tool has been used to highlight not only the main critical points of the infrastructure, where a high level of distraction is recorded, but also the various interactions with different road users (pedestrians, vehicles, buses, wheelchairs, cyclists). To confirm the critical aspects of the infrastructure and the trend of workload, a similar circuit was reproduced in a bicycle simulator, which also allowed a meaningful comparison of cycling behaviour. The innovative component of this paper is a comparison between a real test, held in Stockholm, and a simulator where the same scenario has been represented, in order to highlight the objective differences in behaviour. The cycling performance was also evaluated both from an objective point of view, with the count of frames related to each category of visualization, and from a subjective one, through the questionnaires. The results show the crossing as a critical aspect because only 4/3% fixation is required for both simulated and real tests to confirm the significance of the comparison between the two experiments. The high attention rate, resulting from frame-by-frame analysis, also points to a clear difference in the perception of users, who feel with a low workload.","PeriodicalId":13601,"journal":{"name":"Infrastructures","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43346327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}