Pub Date : 2023-10-05DOI: 10.3390/infrastructures8100142
Pál Hegyi, Attila Borsos, Csaba Koren
The analysis of road network topology has attracted the attention of researchers in the past few decades. In this study, the road topology of housing estates in a few selected Central European countries (Hungary, Austria, Czech Republic, and Slovakia) was analysed. This research was carried out in three steps: (1) the road network topology of different decades from the 1950s to the 1980s was described, (2) the ratio of intersections and dead-ends was investigated, and (3) the connectivity indices were analysed and compared. The research was carried out using ESRI ArcGIS software. The results show that the design of road networks built in different countries is similar in the housing estates studied. When analysing the road networks over time, significant differences could be found in the case of Hungary for housing estates built after the 1960s. In general, connectivity has become more important, as it has gradually increased over time.
{"title":"Evolution of the Road Network Topology of Central European Housing Estates","authors":"Pál Hegyi, Attila Borsos, Csaba Koren","doi":"10.3390/infrastructures8100142","DOIUrl":"https://doi.org/10.3390/infrastructures8100142","url":null,"abstract":"The analysis of road network topology has attracted the attention of researchers in the past few decades. In this study, the road topology of housing estates in a few selected Central European countries (Hungary, Austria, Czech Republic, and Slovakia) was analysed. This research was carried out in three steps: (1) the road network topology of different decades from the 1950s to the 1980s was described, (2) the ratio of intersections and dead-ends was investigated, and (3) the connectivity indices were analysed and compared. The research was carried out using ESRI ArcGIS software. The results show that the design of road networks built in different countries is similar in the housing estates studied. When analysing the road networks over time, significant differences could be found in the case of Hungary for housing estates built after the 1960s. In general, connectivity has become more important, as it has gradually increased over time.","PeriodicalId":13601,"journal":{"name":"Infrastructures","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135483415","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}
Pub Date : 2023-10-05DOI: 10.3390/infrastructures8100141
Michał Wolański
In 2016, Carlos Moreno proposed the concept of “15-minute cities” based on the principles of proximity, diversity, density, and ubiquity. In fact, he re-formulated (“re-invented”) some of the already existing planning principles, making them recognized and desired by non-professionals. Moreno, however, paid little attention to the external connectivity of neighborhoods, assuming that most needs would be satisfied locally. This paper aims to discuss the concept of “15-minute cities” from the transport planning point of view and investigate how the concept can contribute to such planning. The research review conducted in this paper suggests that similar actions in the past caused a modal shift from the use of cars to public transport, rather than a radical limitation of total transport needs. To simplify, if a neighborhood is well designed, people are more likely to walk, ride a bike, and use public transport, but the majority will still commute outside of the neighborhood for work. In the metropolis of the ideal “15-minute city”, Barcelona, the majority of the inhabitants travel to work either by car or public transport, which proves that they need to move outside the neighborhood. This leads us to the conclusions that (1) “15-minute cities” should incorporate the transit-oriented development concept and include public transport nodes, such as railways or underground stations, as the central point of walkable, multifunctional neighborhoods, and (2) railway/underground station planners should pay more attention to the creation of a proper mix of services at and around the stations according to “15-minute cities” principles. In the future, there should also be more emphasis on re-allocating workplaces to neighborhoods, as well as on researching the actual impact of the (improved and current) “15-minute cities” design on transport volumes.
{"title":"The Potential Role of Railway Stations and Public Transport Nodes in the Development of “15-Minute Cities”","authors":"Michał Wolański","doi":"10.3390/infrastructures8100141","DOIUrl":"https://doi.org/10.3390/infrastructures8100141","url":null,"abstract":"In 2016, Carlos Moreno proposed the concept of “15-minute cities” based on the principles of proximity, diversity, density, and ubiquity. In fact, he re-formulated (“re-invented”) some of the already existing planning principles, making them recognized and desired by non-professionals. Moreno, however, paid little attention to the external connectivity of neighborhoods, assuming that most needs would be satisfied locally. This paper aims to discuss the concept of “15-minute cities” from the transport planning point of view and investigate how the concept can contribute to such planning. The research review conducted in this paper suggests that similar actions in the past caused a modal shift from the use of cars to public transport, rather than a radical limitation of total transport needs. To simplify, if a neighborhood is well designed, people are more likely to walk, ride a bike, and use public transport, but the majority will still commute outside of the neighborhood for work. In the metropolis of the ideal “15-minute city”, Barcelona, the majority of the inhabitants travel to work either by car or public transport, which proves that they need to move outside the neighborhood. This leads us to the conclusions that (1) “15-minute cities” should incorporate the transit-oriented development concept and include public transport nodes, such as railways or underground stations, as the central point of walkable, multifunctional neighborhoods, and (2) railway/underground station planners should pay more attention to the creation of a proper mix of services at and around the stations according to “15-minute cities” principles. In the future, there should also be more emphasis on re-allocating workplaces to neighborhoods, as well as on researching the actual impact of the (improved and current) “15-minute cities” design on transport volumes.","PeriodicalId":13601,"journal":{"name":"Infrastructures","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134975795","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}
Pub Date : 2023-10-04DOI: 10.3390/infrastructures8100140
Eka Oktavia Kurniati, Hee-Jeong Kim
Industrial secondary products (e.g., fly ash, blast furnace slag, and silica fume) have found extensive application as alternative construction materials in conventional manufacturing methods to reduce carbon emissions due to cement usage and solve the waste management problem. To date, additive manufacturing or 3D printing has been massively developed for every material, including cement-based materials. Some possibilities have arisen to incorporate industrial wastes in cement mixtures in 3D printing applications. However, a comprehensive study about fly ash (FA), ground granulated blast-furnace slag (GGBFS), and silica fume (SF) usage in 3D-printed materials needs to be conducted. This paper shows that some aspects of 3D printing, such as printability, buildability, and rheological properties, need to be considered, and waste materials affect these fresh mixture properties. Applying waste materials as supplementary cementitious materials also gives different mechanical properties and durability performances. Furthermore, the environmental and economic benefits of 3D-printed and conventional materials are compared. The results show that 3D printing methods can enhance the environmental and economic benefits while maintaining the performance of materials created using traditional methods. Studying industrial waste application in 3D printing has become a promising way to develop sustainable materials in this digitalization era.
{"title":"Utilizing Industrial By-Products for Sustainable Three-Dimensional-Printed Infrastructure Applications: A Comprehensive Review","authors":"Eka Oktavia Kurniati, Hee-Jeong Kim","doi":"10.3390/infrastructures8100140","DOIUrl":"https://doi.org/10.3390/infrastructures8100140","url":null,"abstract":"Industrial secondary products (e.g., fly ash, blast furnace slag, and silica fume) have found extensive application as alternative construction materials in conventional manufacturing methods to reduce carbon emissions due to cement usage and solve the waste management problem. To date, additive manufacturing or 3D printing has been massively developed for every material, including cement-based materials. Some possibilities have arisen to incorporate industrial wastes in cement mixtures in 3D printing applications. However, a comprehensive study about fly ash (FA), ground granulated blast-furnace slag (GGBFS), and silica fume (SF) usage in 3D-printed materials needs to be conducted. This paper shows that some aspects of 3D printing, such as printability, buildability, and rheological properties, need to be considered, and waste materials affect these fresh mixture properties. Applying waste materials as supplementary cementitious materials also gives different mechanical properties and durability performances. Furthermore, the environmental and economic benefits of 3D-printed and conventional materials are compared. The results show that 3D printing methods can enhance the environmental and economic benefits while maintaining the performance of materials created using traditional methods. Studying industrial waste application in 3D printing has become a promising way to develop sustainable materials in this digitalization era.","PeriodicalId":13601,"journal":{"name":"Infrastructures","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135597030","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}
Pub Date : 2023-10-02DOI: 10.3390/infrastructures8100139
Sina Nasiri, Rahmat Madandoust, Malek Mohammad Ranjbar
The impact of the calcination temperature and grinding time on the mechanical properties and durability of limestone-calcined clay concrete (LC3) is crucial. In this research, calcined clay was produced within the temperature range of 700 °C to 900 °C, and the grinding time varied from 15 to 120 min. This study examines compressive strength and chloride penetration resistance using the rapid chloride migration test on LC3 concrete over a period of 180 days. The findings reveal that clay calcined at 800 °C for 120 min exhibited the highest specific surface area compared to other calcined clays. Furthermore, the compressive strength of LC3 concrete incorporating clay calcined at 800 °C for 60 min surpassed that of other mixtures investigated. Additionally, the chloride diffusion coefficient of LC3 concrete with calcined clay prepared at 800 °C for 120 min was lower than other mixtures.
{"title":"Investigating the Calcination Temperature and Grinding Time of Calcined Clay on the Mechanical Properties and Durability of LC3 Concrete","authors":"Sina Nasiri, Rahmat Madandoust, Malek Mohammad Ranjbar","doi":"10.3390/infrastructures8100139","DOIUrl":"https://doi.org/10.3390/infrastructures8100139","url":null,"abstract":"The impact of the calcination temperature and grinding time on the mechanical properties and durability of limestone-calcined clay concrete (LC3) is crucial. In this research, calcined clay was produced within the temperature range of 700 °C to 900 °C, and the grinding time varied from 15 to 120 min. This study examines compressive strength and chloride penetration resistance using the rapid chloride migration test on LC3 concrete over a period of 180 days. The findings reveal that clay calcined at 800 °C for 120 min exhibited the highest specific surface area compared to other calcined clays. Furthermore, the compressive strength of LC3 concrete incorporating clay calcined at 800 °C for 60 min surpassed that of other mixtures investigated. Additionally, the chloride diffusion coefficient of LC3 concrete with calcined clay prepared at 800 °C for 120 min was lower than other mixtures.","PeriodicalId":13601,"journal":{"name":"Infrastructures","volume":"124 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135829065","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}
Tunnel face extrusion rigidity is an important factor for solving stress–strain problems in loose ground conditions. In previous studies, the effect of horizontal and vertical soil layering on tunnel excavation face stability in the presence of longitudinal fiberglass dowels has not been studied. Therefore, in this study, the effect of fiberglass dowels on the stability of the tunnel face in layered soil has been investigated. In this matter, the best dowel arrangement for minimizing the excavation face extrusion in the case of two-layer soil (horizontal or vertical) has been focused on. For this purpose, firstly, a 3D numerical model was validated based on field data provided previously, and then a 3D numerical tunnel was developed in FLAC3D, adopting the Mohr–Coulomb failure criterion. In continuation, the effect of tunnel diameter, initial pressure ranging from 0.5 to 1.5 MPa, and different placement angles of fiberglass dowels ranging from 0 to 9 degrees, with respect to the tunnel longitudinal axes on the tunnel face extrusion, have been investigated. In the case of horizontal layering, the results showed that the maximum extrusion rate is significantly increased where the elasticity modulus of the soil is reduced. In addition, comparing the maximum extrusion in vertical and horizontal layering, it was found that its value in the horizontal mode is much higher than in the vertical. Additionally, the extrusion of the tunnel face has changed significantly due to an alteration in the initial stress. Finally, it was discovered that tunnel face extrusion is not significantly affected by altering the angle of the fiberglass dowels.
{"title":"Numerical Investigation of the Effect of Longitudinal Fiberglass Dowels on Tunnel Face Support in Layered Soils","authors":"Morteza Esmaeili, Jafar Hosseini Hosseini Manoujan, Jafar Chalabii, Farshad Astaraki, Majid Movahedi Rad","doi":"10.3390/infrastructures8100138","DOIUrl":"https://doi.org/10.3390/infrastructures8100138","url":null,"abstract":"Tunnel face extrusion rigidity is an important factor for solving stress–strain problems in loose ground conditions. In previous studies, the effect of horizontal and vertical soil layering on tunnel excavation face stability in the presence of longitudinal fiberglass dowels has not been studied. Therefore, in this study, the effect of fiberglass dowels on the stability of the tunnel face in layered soil has been investigated. In this matter, the best dowel arrangement for minimizing the excavation face extrusion in the case of two-layer soil (horizontal or vertical) has been focused on. For this purpose, firstly, a 3D numerical model was validated based on field data provided previously, and then a 3D numerical tunnel was developed in FLAC3D, adopting the Mohr–Coulomb failure criterion. In continuation, the effect of tunnel diameter, initial pressure ranging from 0.5 to 1.5 MPa, and different placement angles of fiberglass dowels ranging from 0 to 9 degrees, with respect to the tunnel longitudinal axes on the tunnel face extrusion, have been investigated. In the case of horizontal layering, the results showed that the maximum extrusion rate is significantly increased where the elasticity modulus of the soil is reduced. In addition, comparing the maximum extrusion in vertical and horizontal layering, it was found that its value in the horizontal mode is much higher than in the vertical. Additionally, the extrusion of the tunnel face has changed significantly due to an alteration in the initial stress. Finally, it was discovered that tunnel face extrusion is not significantly affected by altering the angle of the fiberglass dowels.","PeriodicalId":13601,"journal":{"name":"Infrastructures","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135924164","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}
Pub Date : 2023-09-23DOI: 10.3390/infrastructures8100137
Abderrazak Barkat, Said Kenai, Belkasem Menadi, El-Hadj Kadri, Jamal Khatib
Self-compacting concrete (SCC) production is a complex operation that requires finding a good combination and suitable dosages for its constituents. Several formulation methods have been developed to meet the workability requirements of SCC. Mortar spread is used to estimate SCC’s rheological properties, but the use of supplementary cementitious materials, such as metakaolin, could affect the accuracy of the estimation. In this paper, the relationships between the fresh properties of local-metakaolin (MK)-based SCC and the spreading of its mortar portion were investigated. The results showed the existence of good correlations between the spreading of mortar portion of SCC and its fresh state properties. The partial substitution of cement with MK did not affect these correlations. The mortar flow should be chosen according to the required rheological properties of the SCC. This can be achieved by using an appropriate viscosity-enhancing agent (VEA).
{"title":"Relationships between Mortar Spread and the Fresh Properties of SCC Containing Local Metakaolin","authors":"Abderrazak Barkat, Said Kenai, Belkasem Menadi, El-Hadj Kadri, Jamal Khatib","doi":"10.3390/infrastructures8100137","DOIUrl":"https://doi.org/10.3390/infrastructures8100137","url":null,"abstract":"Self-compacting concrete (SCC) production is a complex operation that requires finding a good combination and suitable dosages for its constituents. Several formulation methods have been developed to meet the workability requirements of SCC. Mortar spread is used to estimate SCC’s rheological properties, but the use of supplementary cementitious materials, such as metakaolin, could affect the accuracy of the estimation. In this paper, the relationships between the fresh properties of local-metakaolin (MK)-based SCC and the spreading of its mortar portion were investigated. The results showed the existence of good correlations between the spreading of mortar portion of SCC and its fresh state properties. The partial substitution of cement with MK did not affect these correlations. The mortar flow should be chosen according to the required rheological properties of the SCC. This can be achieved by using an appropriate viscosity-enhancing agent (VEA).","PeriodicalId":13601,"journal":{"name":"Infrastructures","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135967350","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}
Pub Date : 2023-09-15DOI: 10.3390/infrastructures8090136
Kay Smarsly, Kosmas Dragos, Jan Stührenberg, Mathias Worm
With the advancements in information, communication, and sensing technologies, structural health monitoring (SHM) has matured into a substantial pillar of infrastructure maintenance. In particular, wireless sensor networks have gradually been incorporated into SHM, leveraging new opportunities towards reduced installation efforts and enhanced flexibility and scalability, as compared to cable-based SHM systems. However, wireless sensor nodes are installed at fixed locations and need to be employed at high density to reliably monitor large infrastructure, which may cause high installation costs. Furthermore, the limited power autonomy of wireless sensor networks, installed at fixed locations for unattended long-term operation, still represents a significant constraint when deploying stationary wireless sensor nodes for SHM. To resolve the critical constraints stemming from costly high-density deployment and limited power autonomy, a mobile structural health monitoring concept based on legged robots is proposed in the study reported in this paper. The study explores the accuracy and cost-efficiency of deploying legged robots in dense measurement setups for wireless SHM of civil infrastructure, aiming to gain insights into the advantages of mobile wireless sensor nodes in general and of legged robots in particular, in terms of obtaining rich information on the structural condition. As is shown in this paper, the legged robots, as compared to stationary wireless sensor nodes, require a smaller number of nodes to be deployed in civil infrastructure to achieve rich sensor information, entailing more cost-efficient, yet accurate, SHM. In conclusion, this study represents a first step towards autonomous robotic fleets advancing structural health monitoring.
{"title":"Mobile Structural Health Monitoring Based on Legged Robots","authors":"Kay Smarsly, Kosmas Dragos, Jan Stührenberg, Mathias Worm","doi":"10.3390/infrastructures8090136","DOIUrl":"https://doi.org/10.3390/infrastructures8090136","url":null,"abstract":"With the advancements in information, communication, and sensing technologies, structural health monitoring (SHM) has matured into a substantial pillar of infrastructure maintenance. In particular, wireless sensor networks have gradually been incorporated into SHM, leveraging new opportunities towards reduced installation efforts and enhanced flexibility and scalability, as compared to cable-based SHM systems. However, wireless sensor nodes are installed at fixed locations and need to be employed at high density to reliably monitor large infrastructure, which may cause high installation costs. Furthermore, the limited power autonomy of wireless sensor networks, installed at fixed locations for unattended long-term operation, still represents a significant constraint when deploying stationary wireless sensor nodes for SHM. To resolve the critical constraints stemming from costly high-density deployment and limited power autonomy, a mobile structural health monitoring concept based on legged robots is proposed in the study reported in this paper. The study explores the accuracy and cost-efficiency of deploying legged robots in dense measurement setups for wireless SHM of civil infrastructure, aiming to gain insights into the advantages of mobile wireless sensor nodes in general and of legged robots in particular, in terms of obtaining rich information on the structural condition. As is shown in this paper, the legged robots, as compared to stationary wireless sensor nodes, require a smaller number of nodes to be deployed in civil infrastructure to achieve rich sensor information, entailing more cost-efficient, yet accurate, SHM. In conclusion, this study represents a first step towards autonomous robotic fleets advancing structural health monitoring.","PeriodicalId":13601,"journal":{"name":"Infrastructures","volume":"176 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135353851","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}
Pub Date : 2023-09-13DOI: 10.3390/infrastructures8090135
Andrea Miano, Annalisa Mele, Irene Della Ragione, Antimo Fiorillo, Marco Di Ludovico, Andrea Prota
The Italian infrastructure network of roads and bridges is one of the most complex in the world due to the territory orography. Italy is strongly interested in seismic and hydrogeological hazards, and, in addition, degradation and obsolescence phenomena are common in infrastructures nowadays approaching the end of their nominal life. Furthermore, these infrastructures are subjected to continuous traffic load increase over time. In 2020, the Italian Ministry of Infrastructure and Transport (MIT) published the guidelines for risk classification and management, safety assessment, and monitoring of existing bridges (LG2020) as an attempt to unify the multiple procedures of inspection, monitoring, and maintenance of infrastructures. The multilevel approach proposed in the Italian guidelines for the management of the complex existing system of bridges is herein discussed and investigated, focusing on an operational methodology to evaluate the impact of structural defects on the risk assessment. This study aims to develop an operational methodology for the application of the procedure generically depicted in the LG2020 for the attribution of the level of defectiveness based on the outcomes of the periodical inspections. In particular, such a methodology is applied to two of the most widespread bridge structural typologies in the Mediterranean area: reinforced concrete (RC) and prestressed RC (PRC) bridges. The defects’ extent and level to structural members are associated with the proposed procedure for different bridge risk ratings. The work presents a useful tool to proceed from the outcomes of the inspections to the assignment of a level of defectiveness for the bridge, which enters into the risk assessment. This is to drive decision-makers in the definition of future actions and interventions, such as the detailed assessment of safety level and relevant strengthening interventions or installation of continuous monitoring systems.
{"title":"Impact of the Structural Defects on Risk Assessment of Concrete Bridges According to the Italian Guidelines 2020","authors":"Andrea Miano, Annalisa Mele, Irene Della Ragione, Antimo Fiorillo, Marco Di Ludovico, Andrea Prota","doi":"10.3390/infrastructures8090135","DOIUrl":"https://doi.org/10.3390/infrastructures8090135","url":null,"abstract":"The Italian infrastructure network of roads and bridges is one of the most complex in the world due to the territory orography. Italy is strongly interested in seismic and hydrogeological hazards, and, in addition, degradation and obsolescence phenomena are common in infrastructures nowadays approaching the end of their nominal life. Furthermore, these infrastructures are subjected to continuous traffic load increase over time. In 2020, the Italian Ministry of Infrastructure and Transport (MIT) published the guidelines for risk classification and management, safety assessment, and monitoring of existing bridges (LG2020) as an attempt to unify the multiple procedures of inspection, monitoring, and maintenance of infrastructures. The multilevel approach proposed in the Italian guidelines for the management of the complex existing system of bridges is herein discussed and investigated, focusing on an operational methodology to evaluate the impact of structural defects on the risk assessment. This study aims to develop an operational methodology for the application of the procedure generically depicted in the LG2020 for the attribution of the level of defectiveness based on the outcomes of the periodical inspections. In particular, such a methodology is applied to two of the most widespread bridge structural typologies in the Mediterranean area: reinforced concrete (RC) and prestressed RC (PRC) bridges. The defects’ extent and level to structural members are associated with the proposed procedure for different bridge risk ratings. The work presents a useful tool to proceed from the outcomes of the inspections to the assignment of a level of defectiveness for the bridge, which enters into the risk assessment. This is to drive decision-makers in the definition of future actions and interventions, such as the detailed assessment of safety level and relevant strengthening interventions or installation of continuous monitoring systems.","PeriodicalId":13601,"journal":{"name":"Infrastructures","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135781625","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}
Pub Date : 2023-09-11DOI: 10.3390/infrastructures8090134
DingXin Cheng, Lerose Lane
Single chip seals are used by many agencies to maintain or preserve their roadways. While the construction and performance of single chip seals can be easily found from literature, the construction of double chip seals with and without paving fabric or paving mats is still not common. This paper investigates four double chip seal strategies used in a pilot project constructed on US 395 in Inyo County, California, by Caltrans. Within the double chip seal project limits, eight Performance Evaluation Sections (PESs) using four treatment strategies were established for detailed performance monitoring and evaluation: 1—a 3/8-inch asphalt rubber chip seal followed by a 1/4-inch PME chip seal without pavement-reinforcing fabric (PRF) or a paving mat as a control section; 2—a 3/8-inch PME chip seal over PRF, followed by a 1/4-inch PME chip seal; 3—a 3/8-inch PME chip seal over a paving mat, followed by a 1/4-inch PME chip seal; and 4—an asphalt rubber 3/8-inch chip seal over a paving mat, followed by a 1/4-inch PME chip seal. This pilot project was monitored during construction and evaluated 1 year later to help identify any construction issues and was used to improve the specifications and performance of Caltrans’ chip seals. This paper presents the initial findings following construction, and the one-year performance of the pilot project and lessons learned. The findings presented were accomplished by using these four treatment strategies on a highway with a very adverse high desert climate type and high traffic volumes. Project reviews are also planned for up to seven years to determine the long-term project performance.
{"title":"Lessons Learned from the Construction and Initial Performance of a Double Chip Seal in a Paving Mat Pilot Project","authors":"DingXin Cheng, Lerose Lane","doi":"10.3390/infrastructures8090134","DOIUrl":"https://doi.org/10.3390/infrastructures8090134","url":null,"abstract":"Single chip seals are used by many agencies to maintain or preserve their roadways. While the construction and performance of single chip seals can be easily found from literature, the construction of double chip seals with and without paving fabric or paving mats is still not common. This paper investigates four double chip seal strategies used in a pilot project constructed on US 395 in Inyo County, California, by Caltrans. Within the double chip seal project limits, eight Performance Evaluation Sections (PESs) using four treatment strategies were established for detailed performance monitoring and evaluation: 1—a 3/8-inch asphalt rubber chip seal followed by a 1/4-inch PME chip seal without pavement-reinforcing fabric (PRF) or a paving mat as a control section; 2—a 3/8-inch PME chip seal over PRF, followed by a 1/4-inch PME chip seal; 3—a 3/8-inch PME chip seal over a paving mat, followed by a 1/4-inch PME chip seal; and 4—an asphalt rubber 3/8-inch chip seal over a paving mat, followed by a 1/4-inch PME chip seal. This pilot project was monitored during construction and evaluated 1 year later to help identify any construction issues and was used to improve the specifications and performance of Caltrans’ chip seals. This paper presents the initial findings following construction, and the one-year performance of the pilot project and lessons learned. The findings presented were accomplished by using these four treatment strategies on a highway with a very adverse high desert climate type and high traffic volumes. Project reviews are also planned for up to seven years to determine the long-term project performance.","PeriodicalId":13601,"journal":{"name":"Infrastructures","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136023278","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}
Pub Date : 2023-09-05DOI: 10.3390/infrastructures8090133
Florin Pavel, Robert Vladut
This paper is focused on the evaluation of the liquefaction hazard for different sites in Romania. To this aim, a database of 139 ground motions recorded during Vrancea intermediate-depth earthquakes having moment magnitudes MW ≥ 6.0 is employed for the evaluation of the equivalent number of cycles for this seismic source. Several functional forms for the empirical evaluation of the equivalent number of cycles considering various seismological or engineering parameters are tested and evaluated. The regression analysis shows smaller uncertainties for the empirical models based on ground motion engineering parameters. Considering the lack of information in terms of engineering parameters, a simpler empirical model which accounts for the earthquake magnitude, source–site distance and soil conditions is selected for the liquefaction hazard analysis. Based on the proposed empirical model, specific magnitude scaling factors for Vrancea intermediate-depth earthquakes are proposed for the first time as well. The liquefaction hazard analysis is performed for sites whose seismic hazard is generated by either the Vrancea intermediate-depth seismic source or by local shallow crustal seismic sources. In the case of some of the selected sites, liquefaction phenomena were observed during past large-magnitude earthquakes. Unlike previous studies dealing with liquefaction analyses for sites in Romania, in this research, the hazard assessment is performed for various ground motion levels evaluated based on probabilistic seismic hazard assessment. Liquefaction hazard curves are constructed for each analyzed site. The results of the liquefaction hazard analysis show that this phenomenon is more likely to occur in the areas exposed to Vrancea intermediate-depth earthquakes, compared to the areas affected by local shallow earthquakes. In the case of the analyzed soil profiles from Bucharest, Craiova and Ianca, the minimum liquefaction safety factors less than one even for seismic hazard levels having mean return periods of 100 years and less.
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