Cortney Natalicchio, H. Al-Khateeb, M. Chajes, Z. Wu, Harry W. Shenton III
Structural Health Monitoring (SHM) systems, in combination with controlled load tests, can provide valuable data for calibrating high fidelity bridge models, which can then be used for evaluating the long-term performance of the bridge, improved load ratings, and permit vehicle evaluation. The objective of this research was to calibrate a 3D model of the Indian River Inlet (IRIB) cable-stayed bridge, using strains recorded by the bridge SHM system during a controlled load test. The bridge was modeled in STAAD-Pro and calibrated using a pre-commercialized software platform that uses a Generic Algorithm to minimize the error between the measured and predicted strains. The calibration parameters were the elastic modulus of groups of the main longitudinal edge girder/deck elements, which once calibrated, could be related to the measured concrete strength of the members. Four different models were investigated, using 6, 10, 14, and 18 parameter element groups of the edge girder members. Of the different models, the 14 and 18 parameter models yielded the best results. The “design” model yielded errors as high as 42% when compared to the measured strains; the error was less than 10% for the majority of measurements for the 14-parameter model. Including the effect of the traffic barriers in the model, the weighted average concrete strength of the calibrated model was within 4% of the measured weighted strength. The calibration was shown to be insensitive to measurement noise and was validated using several unique single and multi-vehicle load cases that were heavier and more offset from the centerline of the bridge. The calibration procedure was able to capture the variability in flexural stiffness of the edge girders due to the variability of the concrete, resulting in significantly better agreement between the live load measured strains and the model predicted strains.
{"title":"Model calibration of a long-span concrete cable-stayed bridge based on structural health monitoring data: Influence of concrete variability","authors":"Cortney Natalicchio, H. Al-Khateeb, M. Chajes, Z. Wu, Harry W. Shenton III","doi":"10.3233/brs-220195","DOIUrl":"https://doi.org/10.3233/brs-220195","url":null,"abstract":"Structural Health Monitoring (SHM) systems, in combination with controlled load tests, can provide valuable data for calibrating high fidelity bridge models, which can then be used for evaluating the long-term performance of the bridge, improved load ratings, and permit vehicle evaluation. The objective of this research was to calibrate a 3D model of the Indian River Inlet (IRIB) cable-stayed bridge, using strains recorded by the bridge SHM system during a controlled load test. The bridge was modeled in STAAD-Pro and calibrated using a pre-commercialized software platform that uses a Generic Algorithm to minimize the error between the measured and predicted strains. The calibration parameters were the elastic modulus of groups of the main longitudinal edge girder/deck elements, which once calibrated, could be related to the measured concrete strength of the members. Four different models were investigated, using 6, 10, 14, and 18 parameter element groups of the edge girder members. Of the different models, the 14 and 18 parameter models yielded the best results. The “design” model yielded errors as high as 42% when compared to the measured strains; the error was less than 10% for the majority of measurements for the 14-parameter model. Including the effect of the traffic barriers in the model, the weighted average concrete strength of the calibrated model was within 4% of the measured weighted strength. The calibration was shown to be insensitive to measurement noise and was validated using several unique single and multi-vehicle load cases that were heavier and more offset from the centerline of the bridge. The calibration procedure was able to capture the variability in flexural stiffness of the edge girders due to the variability of the concrete, resulting in significantly better agreement between the live load measured strains and the model predicted strains.","PeriodicalId":43279,"journal":{"name":"Bridge Structures","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2022-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48124065","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}
Northeast extreme tee (NEXT) precast prestressed concrete beams have recently emerged as a promising solution to accelerate bridge construction and enhance the sustainability of bridges. To date, several studies on the live load distribution factor (LLDF) for moment and shear in NEXT F beam bridges have been reported, which indicated that using the AASHTO LRFD LLDF for moment in NEXT F beam bridges could provide a sufficient safety margin; however, a 20% increase in the LRFD LLDF for shear was recommended for the safety of shear design. This paper intended to investigate the required transverse shear reinforcements in NEXT F beam bridges by using a factor of 1.2 for the LRFD LLDF for shear. A comprehensive study was carried out by considering various parameters, including concrete strength, beam section, bridge section, and span length. Results from this study showed that providing the minimum transverse shear reinforcement could offer a sufficient safety margin for the shear design of NEXT F beam bridges, even with an increase of 20% on the LRFD LLDF for shear. It is recommended that a factor of 1.2 be used for the LRFD LLDF for shear to ensure a safe design of NEXT F beam bridges, though the minimum transverse reinforcements will be likely to control the shear design.
{"title":"Shear design of precast prestressed concrete NEXT beam bridges: A critical assessment","authors":"Jianwei Huang","doi":"10.3233/brs-220198","DOIUrl":"https://doi.org/10.3233/brs-220198","url":null,"abstract":"Northeast extreme tee (NEXT) precast prestressed concrete beams have recently emerged as a promising solution to accelerate bridge construction and enhance the sustainability of bridges. To date, several studies on the live load distribution factor (LLDF) for moment and shear in NEXT F beam bridges have been reported, which indicated that using the AASHTO LRFD LLDF for moment in NEXT F beam bridges could provide a sufficient safety margin; however, a 20% increase in the LRFD LLDF for shear was recommended for the safety of shear design. This paper intended to investigate the required transverse shear reinforcements in NEXT F beam bridges by using a factor of 1.2 for the LRFD LLDF for shear. A comprehensive study was carried out by considering various parameters, including concrete strength, beam section, bridge section, and span length. Results from this study showed that providing the minimum transverse shear reinforcement could offer a sufficient safety margin for the shear design of NEXT F beam bridges, even with an increase of 20% on the LRFD LLDF for shear. It is recommended that a factor of 1.2 be used for the LRFD LLDF for shear to ensure a safe design of NEXT F beam bridges, though the minimum transverse reinforcements will be likely to control the shear design.","PeriodicalId":43279,"journal":{"name":"Bridge Structures","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2022-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46224069","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}
Accidental damage to prestressed concrete bridge girders may occur due to impact by over-height vehicles on the bottom of the girder, or the top flange of the girder may be damaged during deck removal and replacement operations. Since stress checks at service loads are an important component of design for prestressed concrete beams, serviceability-based stress checks should be considered when assessing the structural condition of damaged girders. In this paper, step-by-step theoretical calculations are used to develop equations for estimating service load stress changes due to physical damage (partial loss of concrete section and strands) based on a differential approach. The effects of lack of symmetry in the damaged cross section is considered in the calculations. A spreadsheet-based program is developed to calculate complex section property values for the damaged sections. The accuracy of the developed equations was verified using a finite element model of a prestressed beam under undamaged and damaged conditions. Reasonably good agreement was noted between the predicted stress changes and the finite element results.
{"title":"Stress change calculations in accidentally damaged prestressed bridge girders","authors":"H. Tabatabai, A. Nabizadeh","doi":"10.3233/brs-220197","DOIUrl":"https://doi.org/10.3233/brs-220197","url":null,"abstract":"Accidental damage to prestressed concrete bridge girders may occur due to impact by over-height vehicles on the bottom of the girder, or the top flange of the girder may be damaged during deck removal and replacement operations. Since stress checks at service loads are an important component of design for prestressed concrete beams, serviceability-based stress checks should be considered when assessing the structural condition of damaged girders. In this paper, step-by-step theoretical calculations are used to develop equations for estimating service load stress changes due to physical damage (partial loss of concrete section and strands) based on a differential approach. The effects of lack of symmetry in the damaged cross section is considered in the calculations. A spreadsheet-based program is developed to calculate complex section property values for the damaged sections. The accuracy of the developed equations was verified using a finite element model of a prestressed beam under undamaged and damaged conditions. Reasonably good agreement was noted between the predicted stress changes and the finite element results.","PeriodicalId":43279,"journal":{"name":"Bridge Structures","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2022-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44125620","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}
The rupture of a cable in cable-supported bridges is an accidental condition that should be considered during the design phase due the impact that this situation could have on the structural safety of the bridge and users. For that reason, design guidelines suggest carrying out a pseudo-static analysis where the failing cable is replaced by a load of the same magnitude as the pre-rupture tension but applied in the opposite direction and multiplied by a dynamic amplification factor (DAF) between 1.5 and 2.0. Previous studies in cable-stayed bridges have shown that the pseudo-static approach may not be suitable. Due to the wide use of extradosed bridges in infrastructure projects around the world, a computational analysis was performed in this investigation to estimate the dynamic amplification factors of extradosed bridge girders and cables when sudden failure of an extradosed cable occurs. The main goal of the study is to determine whether the pseudo-static approach suggested in the guidelines is acceptable. Linear response history analyses were performed by using computational models of extradosed bridges in which the girder stiffness and the suspension (lateral or central) and cable layout (fan or harp) of the cables were modified. From the analysis, the DAFs were calculated and compared to those recommended in the design guidelines. The calculated DAFs for the axial forces and bending moment in the girder of the bridges and for the axial forces in the extradosed cables were smaller than 2.0. However, in some cases the DAF for shear forces were higher than 2.0, especially when the girder stiffness was relatively low. The results indicate that the recommendations of the design guidelines are adequate for extradosed bridges, which is a result of the relatively high stiffness of the girder and low inclination of extradosed cables. Despite this, response history analyses like the one performed in this study are recommended to assess the response of the bridge under cable breakage.
{"title":"Dynamic amplification factors of girder and cables of extradosed bridges during sudden cable failure","authors":"Homer Buelvas, J. Benjumea, Gustavo Chio","doi":"10.3233/brs-210189","DOIUrl":"https://doi.org/10.3233/brs-210189","url":null,"abstract":"The rupture of a cable in cable-supported bridges is an accidental condition that should be considered during the design phase due the impact that this situation could have on the structural safety of the bridge and users. For that reason, design guidelines suggest carrying out a pseudo-static analysis where the failing cable is replaced by a load of the same magnitude as the pre-rupture tension but applied in the opposite direction and multiplied by a dynamic amplification factor (DAF) between 1.5 and 2.0. Previous studies in cable-stayed bridges have shown that the pseudo-static approach may not be suitable. Due to the wide use of extradosed bridges in infrastructure projects around the world, a computational analysis was performed in this investigation to estimate the dynamic amplification factors of extradosed bridge girders and cables when sudden failure of an extradosed cable occurs. The main goal of the study is to determine whether the pseudo-static approach suggested in the guidelines is acceptable. Linear response history analyses were performed by using computational models of extradosed bridges in which the girder stiffness and the suspension (lateral or central) and cable layout (fan or harp) of the cables were modified. From the analysis, the DAFs were calculated and compared to those recommended in the design guidelines. The calculated DAFs for the axial forces and bending moment in the girder of the bridges and for the axial forces in the extradosed cables were smaller than 2.0. However, in some cases the DAF for shear forces were higher than 2.0, especially when the girder stiffness was relatively low. The results indicate that the recommendations of the design guidelines are adequate for extradosed bridges, which is a result of the relatively high stiffness of the girder and low inclination of extradosed cables. Despite this, response history analyses like the one performed in this study are recommended to assess the response of the bridge under cable breakage.","PeriodicalId":43279,"journal":{"name":"Bridge Structures","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47152976","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}
Frequency-based analysis techniques such as response spectrum analysis (RSA) are widely used for designing bridges in seismically active regions. Two well-known analysis procedures that underlie RSA are the solution of the eigenproblem and the approximation of the solution to the eigenproblem (i.e., approximation of eigenvectors and eigenvalues) through use of force-dependent Ritz vectors. While frequency-based methods have achieved widespread adoption in practice, certain simplifications remain common, such as neglecting soil-structure interaction (SSI) due to a fixed-base assumption. In the present study, frequency-based techniques packaged within a research version of a design-oriented computational tool are employed to analyze, assess, and compare results obtained from RSA with use of the eigenanalysis, and separately, Ritz vector approaches. Importantly, for the bridge configurations analyzed, SSI is taken into account. As outcomes, the potential benefits of the Ritz vector approach (as well as modeling strategies) are demonstrated. The study outcomes are intended to aid practicing engineers when the need to account for SSI is recognized as pertinent to a given bridge seismic design application.
{"title":"Comparison of eigenanalysis and Ritz vector approaches for response spectrum analysis of soil-pile-bridge systems","authors":"M. Davidson, A. Patil, S. A. Rosenfeld, Z. Zhu","doi":"10.3233/brs-210192","DOIUrl":"https://doi.org/10.3233/brs-210192","url":null,"abstract":"Frequency-based analysis techniques such as response spectrum analysis (RSA) are widely used for designing bridges in seismically active regions. Two well-known analysis procedures that underlie RSA are the solution of the eigenproblem and the approximation of the solution to the eigenproblem (i.e., approximation of eigenvectors and eigenvalues) through use of force-dependent Ritz vectors. While frequency-based methods have achieved widespread adoption in practice, certain simplifications remain common, such as neglecting soil-structure interaction (SSI) due to a fixed-base assumption. In the present study, frequency-based techniques packaged within a research version of a design-oriented computational tool are employed to analyze, assess, and compare results obtained from RSA with use of the eigenanalysis, and separately, Ritz vector approaches. Importantly, for the bridge configurations analyzed, SSI is taken into account. As outcomes, the potential benefits of the Ritz vector approach (as well as modeling strategies) are demonstrated. The study outcomes are intended to aid practicing engineers when the need to account for SSI is recognized as pertinent to a given bridge seismic design application.","PeriodicalId":43279,"journal":{"name":"Bridge Structures","volume":"1 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42450730","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}
Using precast concrete elements in bridge structures has emerged as an economic and durable solution to enhance the sustainability of bridges. The northeast extreme tee (NEXT) beams were recently developed for accelerated bridge construction by the Precast/Prestressed Concrete Institute (PCI). To date, several studies on the live load distribution factor (LLDF) for moment in NEXT F beam bridges have been reported. However, the LLDFs for shear in NEXT F beam bridges are still unclear. In this paper, the lateral distributions of live load shear in NEXT F beam bridges were examined through a comprehensive parametric study. The parameters covered in this study included bridge section, span length, beam section, number of beams, and number of lanes loaded. A validated finite element (FE) modeling technique was employed to analyze the shear behavior of NEXT F beam bridges under the AASHTO HL-93 loading and to determine the LLDFs for shear in NEXT beam bridges. A method for computing the FE-LLDF for shear was proposed for NEXT beam bridges. Results from this study showed that the FE-LLDFs have a similar trend as the AASHTO LFRD-LLDFs. However, it was observed that some LRFD-LLDFs are lower than the FE-LLDFs by up to 14.1%, which implied using the LRFD-LLDFs for shear could result in an unsafe shear design for NEXT beam bridges. It is recommended that a factor of 1.2 be applied to the LRFD-LLDF for shear in NEXT F beam bridges for structural safety and design simplicity.
{"title":"Shear live load analysis of NEXT beam bridges for accelerated bridge construction","authors":"Jianwei Huang","doi":"10.3233/brs-210191","DOIUrl":"https://doi.org/10.3233/brs-210191","url":null,"abstract":"Using precast concrete elements in bridge structures has emerged as an economic and durable solution to enhance the sustainability of bridges. The northeast extreme tee (NEXT) beams were recently developed for accelerated bridge construction by the Precast/Prestressed Concrete Institute (PCI). To date, several studies on the live load distribution factor (LLDF) for moment in NEXT F beam bridges have been reported. However, the LLDFs for shear in NEXT F beam bridges are still unclear. In this paper, the lateral distributions of live load shear in NEXT F beam bridges were examined through a comprehensive parametric study. The parameters covered in this study included bridge section, span length, beam section, number of beams, and number of lanes loaded. A validated finite element (FE) modeling technique was employed to analyze the shear behavior of NEXT F beam bridges under the AASHTO HL-93 loading and to determine the LLDFs for shear in NEXT beam bridges. A method for computing the FE-LLDF for shear was proposed for NEXT beam bridges. Results from this study showed that the FE-LLDFs have a similar trend as the AASHTO LFRD-LLDFs. However, it was observed that some LRFD-LLDFs are lower than the FE-LLDFs by up to 14.1%, which implied using the LRFD-LLDFs for shear could result in an unsafe shear design for NEXT beam bridges. It is recommended that a factor of 1.2 be applied to the LRFD-LLDF for shear in NEXT F beam bridges for structural safety and design simplicity.","PeriodicalId":43279,"journal":{"name":"Bridge Structures","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48161320","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}
Gamze Muratoğlu, Berk Karakuş, A. Caner, Havin Arslan, Nurettin Pelen, Uzay Genişoğlu, B. Atak
On October 30, 2020, an earthquake about 70 km away from the city center of Izmir with a 4.3 million population has shaken the city tremendously and has resulted in destruction of many building type of structures due to an unexpected high soil-amplified vibrations very similar to the Mexico City earthquake in 1985. The bridges at the soil-amplified sites has performed in elastic range with no damage at all. In the city of Izmir, the 42 year old twin bridges located on the main transportation route, were tremendously shaken by the earthquake had observed to have no seismic induced damage. Surprisingly twin bridges suffering from the alkali silica reaction (ASR) over the years did not even pound to each other despite the small size of longitudinal gap between them. As it has been known, the past performance of Turkish designed bridges are typically succesfull with almost no damage as observed in the Van 2011 and Sivrice 2020 earthquake mainly due to allowing movements at their joints and to flexible type of framing. The focus of the paper is given to understand the successful performance of bridges and to investigate the non-pounded twin bridges of the Izmir city. In this scope, a bridge inspection has been performed and the twin bridges have been analyzed for the recorded ground motion. The results have indicated that the structures have been subjected to 0.3 g at their vibration modes and the twin bridges have a synchronized motion due to having the identical vibration mode shape with a period of 1.5 seconds
{"title":"Unexpected soil amplification effect on seismic performance of highway bridges during the Aegean earthquake of October 2020, Mw 6.6","authors":"Gamze Muratoğlu, Berk Karakuş, A. Caner, Havin Arslan, Nurettin Pelen, Uzay Genişoğlu, B. Atak","doi":"10.3233/brs-210190","DOIUrl":"https://doi.org/10.3233/brs-210190","url":null,"abstract":"On October 30, 2020, an earthquake about 70 km away from the city center of Izmir with a 4.3 million population has shaken the city tremendously and has resulted in destruction of many building type of structures due to an unexpected high soil-amplified vibrations very similar to the Mexico City earthquake in 1985. The bridges at the soil-amplified sites has performed in elastic range with no damage at all. In the city of Izmir, the 42 year old twin bridges located on the main transportation route, were tremendously shaken by the earthquake had observed to have no seismic induced damage. Surprisingly twin bridges suffering from the alkali silica reaction (ASR) over the years did not even pound to each other despite the small size of longitudinal gap between them. As it has been known, the past performance of Turkish designed bridges are typically succesfull with almost no damage as observed in the Van 2011 and Sivrice 2020 earthquake mainly due to allowing movements at their joints and to flexible type of framing. The focus of the paper is given to understand the successful performance of bridges and to investigate the non-pounded twin bridges of the Izmir city. In this scope, a bridge inspection has been performed and the twin bridges have been analyzed for the recorded ground motion. The results have indicated that the structures have been subjected to 0.3 g at their vibration modes and the twin bridges have a synchronized motion due to having the identical vibration mode shape with a period of 1.5 seconds","PeriodicalId":43279,"journal":{"name":"Bridge Structures","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47412562","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}
This article proposes a new parameter in evaluating mechanical behaviors of defected bridge spans. It is Moment Cumulative Function of Power Spectral Density (MCF-PSD) based on changes in shape of power spectrum and trained via cumulative function of spectral moment value by deep learning model. This new parameter allows evaluating stiffness attenuation along time, thereby helps to forecast the workability of bridge span. It can identify risky positions in not only a bridge span but also various spans of the same bridge, which proves its sensitivity to the structure’s behavior change over time. This study reveals that training MCF-PSD using cumulative function algorithm has gained outstanding results in comparison with previous studies in structural quality assessment. Therefore, it fulfills criteria of evaluating the damage level in a structure and also fosters new development of defect diagnosis and forecast. Conclusions from this study show that the change of this function is the basis to evaluate difference among measurement positions in the same span or among different spans of the same bridge and behaviors at different positions in the same span. Therefore, MCF-PSD is more sensitive than other parameters in evaluating the structure’s stiffness attenuation.
{"title":"Structural health monitoring of bridge spans using Moment Cumulative Functions of Power Spectral Density (MCF-PSD) and deep learning","authors":"Thanh Q. Nguyen, Hoang B. Nguyen","doi":"10.3233/BRS-210183","DOIUrl":"https://doi.org/10.3233/BRS-210183","url":null,"abstract":"This article proposes a new parameter in evaluating mechanical behaviors of defected bridge spans. It is Moment Cumulative Function of Power Spectral Density (MCF-PSD) based on changes in shape of power spectrum and trained via cumulative function of spectral moment value by deep learning model. This new parameter allows evaluating stiffness attenuation along time, thereby helps to forecast the workability of bridge span. It can identify risky positions in not only a bridge span but also various spans of the same bridge, which proves its sensitivity to the structure’s behavior change over time. This study reveals that training MCF-PSD using cumulative function algorithm has gained outstanding results in comparison with previous studies in structural quality assessment. Therefore, it fulfills criteria of evaluating the damage level in a structure and also fosters new development of defect diagnosis and forecast. Conclusions from this study show that the change of this function is the basis to evaluate difference among measurement positions in the same span or among different spans of the same bridge and behaviors at different positions in the same span. Therefore, MCF-PSD is more sensitive than other parameters in evaluating the structure’s stiffness attenuation.","PeriodicalId":43279,"journal":{"name":"Bridge Structures","volume":"17 1","pages":"15-39"},"PeriodicalIF":0.6,"publicationDate":"2021-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3233/BRS-210183","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46871049","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}
Development of multiple structural systems for bridges is useful in the design of new bridges and rehabilitation of existing bridges. This paper briefly presents some existing bridges with multiple structural systems and succinctly discusses design ideas for bridges with such systems. As an example of a bridge with multiple structural systems, the paper presents the reconstruction of a pedestrian suspension bridge in the City of Trilj, Croatia. The new bridge’s load-bearing structure is composed of several structural systems. Namely, the reconstructed bridge is a combination of suspension, cable-stayed and stress-ribbon bridge, which is laterally restrained with horizontal tensioned ropes. Numerical analysis was conducted on the renovated bridge. The results have shown an acceptable levels of stresses and deflections verifying the structural safety of the restored bridge. It is believed that this example of the bridge renovation may be useful in the design of new and strengthening of existing similar bridges.
{"title":"Bridges with multiple structural systems: The example of Trilj Bridge reconstruction in Croatia","authors":"J. Radnić, D. Matešan, I. Banović","doi":"10.3233/BRS-210185","DOIUrl":"https://doi.org/10.3233/BRS-210185","url":null,"abstract":"Development of multiple structural systems for bridges is useful in the design of new bridges and rehabilitation of existing bridges. This paper briefly presents some existing bridges with multiple structural systems and succinctly discusses design ideas for bridges with such systems. As an example of a bridge with multiple structural systems, the paper presents the reconstruction of a pedestrian suspension bridge in the City of Trilj, Croatia. The new bridge’s load-bearing structure is composed of several structural systems. Namely, the reconstructed bridge is a combination of suspension, cable-stayed and stress-ribbon bridge, which is laterally restrained with horizontal tensioned ropes. Numerical analysis was conducted on the renovated bridge. The results have shown an acceptable levels of stresses and deflections verifying the structural safety of the restored bridge. It is believed that this example of the bridge renovation may be useful in the design of new and strengthening of existing similar bridges.","PeriodicalId":43279,"journal":{"name":"Bridge Structures","volume":"17 1","pages":"65-75"},"PeriodicalIF":0.6,"publicationDate":"2021-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3233/BRS-210185","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48239228","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}
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