M. R. Shokrzadeh, Armin Aziminejad, Abdolreza S. Moghaddam
There are several methods for strengthening reinforced concrete joints. Due to the unique properties of FRP (Fiber Reinforced Polymer) composites, the use of FRP laminates is one of the most commonly used techniques. The high cost of preparing concrete surfaces and attaching FRP laminates is a restricting factor for its application in reinforced concrete joint retrofit. Therefore, determining proper configurations that reduce the needed FRP material, as well as the surface preparation required for attaching FRP is an important factor in decreasing the strengthening cost. The proper arrangements of FRP strips can improve their performance in the rehabilitation and retrofit of reinforced concrete joints. To determine the proper configuration of FRP strips, finite element modeling was employed. The connection specimens are modeled in ABAQUS general-purpose finite element software and are classified into 10 general groups. To improve the performance of FRP strip configuration, the determined arrangement is investigated for different thicknesses and different widths of the FRP strips, and their results are compared with those of the connection specimen strengthened with full FRP coverage. The analysis results indicated that the load-bearing capacity of the connection retrofitted by the combined configuration of X-shape and orthogonal strips of FRP is close to that of the specimen with full FRP coverage. In this suitable configuration, the required FRP strips are reduced by about 30% , which decreases the cost and construction works needed for concrete joint rehabilitation.
{"title":"Evaluation of various FRP strengthening configurations for RC beam-column joints","authors":"M. R. Shokrzadeh, Armin Aziminejad, Abdolreza S. Moghaddam","doi":"10.3233/brs-240223","DOIUrl":"https://doi.org/10.3233/brs-240223","url":null,"abstract":"There are several methods for strengthening reinforced concrete joints. Due to the unique properties of FRP (Fiber Reinforced Polymer) composites, the use of FRP laminates is one of the most commonly used techniques. The high cost of preparing concrete surfaces and attaching FRP laminates is a restricting factor for its application in reinforced concrete joint retrofit. Therefore, determining proper configurations that reduce the needed FRP material, as well as the surface preparation required for attaching FRP is an important factor in decreasing the strengthening cost. The proper arrangements of FRP strips can improve their performance in the rehabilitation and retrofit of reinforced concrete joints. To determine the proper configuration of FRP strips, finite element modeling was employed. The connection specimens are modeled in ABAQUS general-purpose finite element software and are classified into 10 general groups. To improve the performance of FRP strip configuration, the determined arrangement is investigated for different thicknesses and different widths of the FRP strips, and their results are compared with those of the connection specimen strengthened with full FRP coverage. The analysis results indicated that the load-bearing capacity of the connection retrofitted by the combined configuration of X-shape and orthogonal strips of FRP is close to that of the specimen with full FRP coverage. In this suitable configuration, the required FRP strips are reduced by about 30% , which decreases the cost and construction works needed for concrete joint rehabilitation.","PeriodicalId":43279,"journal":{"name":"Bridge Structures","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140674262","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}
Web shear buckling of steel plate girders limits their load-carrying capacity in bending. Several analytical models have been suggested in the literature to estimate the shear capacity of plate girders. This paper presents a critical evaluation of several of these analytical models using the data of experimentally tested plate girders available in the literature. It was found that these analytical models make a conservative estimation of critical buckling strength for plate girders with larger slenderness and/or aspect ratios. Although the predicted ultimate shear strength varied across the different analytical models, no particular trend was identified to show that the aspect and/or slenderness ratios influenced the shear strength. A parametrically conducted analysis indicated that the threshold slenderness ratio (to cause buckling in the web panel) decreases with increasing yield strength and aspect ratio. The paper proposes simplified guidelines for the preliminary sizing of steel plate girders by avoiding shear buckling. It has been shown that the sizes of plate girders determined using the proposed guidelines satisfy design requirements for both flexure and shear.
{"title":"Steel plate girders shear strength prediction. A performance comparison of analytical models","authors":"M. M. Rafi, M. A. Bhutto","doi":"10.3233/brs-240221","DOIUrl":"https://doi.org/10.3233/brs-240221","url":null,"abstract":" Web shear buckling of steel plate girders limits their load-carrying capacity in bending. Several analytical models have been suggested in the literature to estimate the shear capacity of plate girders. This paper presents a critical evaluation of several of these analytical models using the data of experimentally tested plate girders available in the literature. It was found that these analytical models make a conservative estimation of critical buckling strength for plate girders with larger slenderness and/or aspect ratios. Although the predicted ultimate shear strength varied across the different analytical models, no particular trend was identified to show that the aspect and/or slenderness ratios influenced the shear strength. A parametrically conducted analysis indicated that the threshold slenderness ratio (to cause buckling in the web panel) decreases with increasing yield strength and aspect ratio. The paper proposes simplified guidelines for the preliminary sizing of steel plate girders by avoiding shear buckling. It has been shown that the sizes of plate girders determined using the proposed guidelines satisfy design requirements for both flexure and shear.","PeriodicalId":43279,"journal":{"name":"Bridge Structures","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140366401","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}
Among the test systems for in-place concrete strength available today, two measure the in-place physical strength, pullout, and cores. Both systems are dealt with in detail in this paper, the pullout systems named LOK-TEST/CAPO-TEST (ASTM C900-19) and coring (ASTM C42/42M-18). Testing in-situ with accurate test systems will reveal effects on the final strength from a potential mix’s over transportation, pumping, consolidation, compaction, and curing. With the LOK-TEST system testing of the pre-installed inserts takes 4–5 minutes each, easily and with only one small suitcase brought along. The CAPO-TEST, originally designed to supplement the LOK-TEST, takes 15–20 minutes for each test to be performed anywhere on a structure without pre-installed inserts. No large holes are left in the structure from coring and thinner elements may be tested without weakening them structurally. The pullout test provides accurately the In-Place Strength without testing cores and the duration is about 15 minutes compared to 3–4 days for coring correctly cured. General robust correlations to strength of standard specimens exist no matter what parameter is considered for normal concrete, even for carbonation of the surface layer. With the systems the cover layer protecting the reinforcement may be checked efficiently and quickly, not at least in areas with dense reinforcement or on slim structures. Bad curing conditions are revealed and the consequences in terms of reduced service life for presence of chlorides or carbonation may be estimated swiftly. This paper is benchmarking 50 years of successful in-situ concrete strength measurements, from studies of the failure mechanism and laboratory/on-site correlations to full scale testing of structures in Europe, Scandinavia, and Canada. Six testing cases with emphasis on pullout and cores are illustrating different applications: Case 1. Production testing at the Great Belt Link, Denmark. Case 2. Service life of bridge pier, Great Belt Link, Denmark. Case 3. Curing of the cover layer evaluated by pullout and conductivity, Denmark. Case 4. Strength testing with CAPO-TEST for further loading of old bridges, Poland. Case 5. In-Situ compressive strength testing of quarantined precast concrete tunnel lining segments using CAPO-TEST, UK. Case 6. Safe and early loading with LOK-TEST, Canada. Other cases are given on www.NDTitans.com
在目前可用的现场混凝土强度测试系统中，有两种可以测量现场物理强度，一种是拉拔，另一种是取芯。本文将详细介绍这两种系统，即名为 LOK-TEST/CAPO-TEST （ASTM C900-19）和取芯（ASTM C42/42M-18）的拉拔系统。使用精确的测试系统进行原位测试，可以揭示潜在混合料在过度运输、泵送、固结、压实和固化过程中对最终强度的影响。使用 LOK-TEST 系统对预装插入件进行测试，每个插入件只需 4-5 分钟，只需携带一个小手提箱即可轻松完成。CAPO-TEST 最初是为补充 LOK-TEST 而设计的，每次测试需要 15-20 分钟，可在没有预装嵌件的任何结构上进行。取芯时不会在结构上留下大孔，可以对较薄的构件进行测试，而不会削弱其结构。拉拔测试无需测试岩芯即可准确提供就地强度，测试时间约为 15 分钟，而正确固化的岩芯测试则需要 3-4 天。无论考虑普通混凝土的任何参数，甚至是表层的碳化，标准试样的强度都存在普遍的稳健相关性。使用该系统可以高效、快速地检测保护钢筋的覆盖层，尤其是在钢筋密集区域或细长结构上。不良的固化条件会被暴露出来，氯化物或碳化的存在会缩短使用寿命，其后果也会被迅速估算出来。本文以 50 年来成功的现浇混凝土强度测量为基准，从失效机理和实验室/现场相关性研究，到欧洲、斯堪的纳维亚半岛和加拿大结构的全面测试。六个测试案例重点介绍了拉拔和取芯的不同应用：案例 1.丹麦 Great Belt Link 的生产测试。案例 2.丹麦 Great Belt Link 桥墩的使用寿命。案例 3.通过拉拔和导电性评估覆盖层的固化情况，丹麦。案例 4.使用 CAPO-TEST 进行强度测试以进一步加载旧桥，波兰。案例 5.使用 CAPO-TEST 对经过检疫的预制混凝土隧道衬砌段进行原位抗压强度测试，英国。案例 6.使用 LOK-TEST 进行安全和早期加载，加拿大。其他案例见 www.NDTitans.com。
{"title":"LOK-TEST and CAPO-TEST pullout for in-situ concrete strength","authors":"Claus Germann Petersen","doi":"10.3233/brs-240220","DOIUrl":"https://doi.org/10.3233/brs-240220","url":null,"abstract":"Among the test systems for in-place concrete strength available today, two measure the in-place physical strength, pullout, and cores. Both systems are dealt with in detail in this paper, the pullout systems named LOK-TEST/CAPO-TEST (ASTM C900-19) and coring (ASTM C42/42M-18). Testing in-situ with accurate test systems will reveal effects on the final strength from a potential mix’s over transportation, pumping, consolidation, compaction, and curing. With the LOK-TEST system testing of the pre-installed inserts takes 4–5 minutes each, easily and with only one small suitcase brought along. The CAPO-TEST, originally designed to supplement the LOK-TEST, takes 15–20 minutes for each test to be performed anywhere on a structure without pre-installed inserts. No large holes are left in the structure from coring and thinner elements may be tested without weakening them structurally. The pullout test provides accurately the In-Place Strength without testing cores and the duration is about 15 minutes compared to 3–4 days for coring correctly cured. General robust correlations to strength of standard specimens exist no matter what parameter is considered for normal concrete, even for carbonation of the surface layer. With the systems the cover layer protecting the reinforcement may be checked efficiently and quickly, not at least in areas with dense reinforcement or on slim structures. Bad curing conditions are revealed and the consequences in terms of reduced service life for presence of chlorides or carbonation may be estimated swiftly. This paper is benchmarking 50 years of successful in-situ concrete strength measurements, from studies of the failure mechanism and laboratory/on-site correlations to full scale testing of structures in Europe, Scandinavia, and Canada. Six testing cases with emphasis on pullout and cores are illustrating different applications: Case 1. Production testing at the Great Belt Link, Denmark. Case 2. Service life of bridge pier, Great Belt Link, Denmark. Case 3. Curing of the cover layer evaluated by pullout and conductivity, Denmark. Case 4. Strength testing with CAPO-TEST for further loading of old bridges, Poland. Case 5. In-Situ compressive strength testing of quarantined precast concrete tunnel lining segments using CAPO-TEST, UK. Case 6. Safe and early loading with LOK-TEST, Canada. Other cases are given on www.NDTitans.com","PeriodicalId":43279,"journal":{"name":"Bridge Structures","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140226202","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 Bronx-Whitestone Bridge was designed during the 1930s in an era of suspension bridges with decks stiffened by shallow plate girders, many of which were subsequently found to be vulnerable to aerodynamic instabilities such as vortex shedding and flutter. Following the occurrence of mild and benign wind-induced oscillations in the first several years after opening in 1939, the bridge has undergone a series of retrofits, from structural solutions such as stay cables, stiffening trusses, and a steel orthotropic deck, to aerodynamic enhancements such as a tuned mass damper and wind fairings. Wind tunnel studies in 2015 confirmed the improved aerodynamic performance due to the recently installed wind fairing system and stiffer orthotropic deck. A subsequent rehabilitation project gave the opportunity to assess measures to further improve the aerodynamic performance of the bridge. A 3 ft (0.91 m) tall solid screen added on top of the median barrier was found to act as an above-deck vertical baffle plate, disrupting the alternating pattern of vortices, reducing the susceptibility of the bridge to instabilities. This led to the conceptual design of a Median Barrier Extension (MBE) comprised of 3 ft (0.91 m) solid transparent acrylic panels fixed to the top of the existing median barrier posts, supported by a tubular steel frame. To ensure this unique barrier modification met current industry safety standards, the MBE design was iterated through a crash analysis study using non-linear finite element models before the final design proceeded to a full-scale physical crash testing program to MASH Test Level 4. This paper presents the full timeline of this innovative retrofit project, from conception during wind tunnel testing, through to design, crashworthiness studies and final construction in 2020. This project has demonstrated that a vertical extension to a median barrier can act as a simple and cost-effective enhancement to the aerodynamic performance of existing bridges.
{"title":"Bronx-Whitestone Bridge: Vertical median barrier extension enhances aerodynamics","authors":"Gavin Daly, Ted Zoli, S. Stoyanoff","doi":"10.3233/brs-230216","DOIUrl":"https://doi.org/10.3233/brs-230216","url":null,"abstract":"The Bronx-Whitestone Bridge was designed during the 1930s in an era of suspension bridges with decks stiffened by shallow plate girders, many of which were subsequently found to be vulnerable to aerodynamic instabilities such as vortex shedding and flutter. Following the occurrence of mild and benign wind-induced oscillations in the first several years after opening in 1939, the bridge has undergone a series of retrofits, from structural solutions such as stay cables, stiffening trusses, and a steel orthotropic deck, to aerodynamic enhancements such as a tuned mass damper and wind fairings. Wind tunnel studies in 2015 confirmed the improved aerodynamic performance due to the recently installed wind fairing system and stiffer orthotropic deck. A subsequent rehabilitation project gave the opportunity to assess measures to further improve the aerodynamic performance of the bridge. A 3 ft (0.91 m) tall solid screen added on top of the median barrier was found to act as an above-deck vertical baffle plate, disrupting the alternating pattern of vortices, reducing the susceptibility of the bridge to instabilities. This led to the conceptual design of a Median Barrier Extension (MBE) comprised of 3 ft (0.91 m) solid transparent acrylic panels fixed to the top of the existing median barrier posts, supported by a tubular steel frame. To ensure this unique barrier modification met current industry safety standards, the MBE design was iterated through a crash analysis study using non-linear finite element models before the final design proceeded to a full-scale physical crash testing program to MASH Test Level 4. This paper presents the full timeline of this innovative retrofit project, from conception during wind tunnel testing, through to design, crashworthiness studies and final construction in 2020. This project has demonstrated that a vertical extension to a median barrier can act as a simple and cost-effective enhancement to the aerodynamic performance of existing bridges.","PeriodicalId":43279,"journal":{"name":"Bridge Structures","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138948965","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}
P. Malla, S. S. Khedmatgozar Dolati, A. Mehrabi, J. Ortiz Polanco, A. Nanni, K. Dinh
The application of Fiber Reinforced Polymer (FRP) materials in concrete structures has been rising due to their several advantages, including lightweight, high tensile strength, ease of installation, and corrosion resistance. They have been mostly implemented for strengthening and repairing existing structures in the form of an externally bonded system, i.e., sheet, jacket, near surface mounted. Furthermore, they have been recently utilized as internal reinforcement of concrete elements in the form of strands, bars, tendons, etc. Although higher durability and performance are associated with the FRP material in some aspects compared to steel, concerns remain regarding damages and defects in this material, many of which are related to their unique features. Importantly, debonding of FRP materials from a concrete surface or within a concrete element has always been an issue resulting in the premature failure of the structure. To this end, concrete elements strengthened or reinforced with FRP materials has to be inspected periodically to detect potential issues and hence prevent any premature failures. This study first determines all possible or potential damages and anomalies attributed to FRP reinforced/strengthened concrete (FRP-RSC) elements. It then investigates Non-Destructive Testing (NDT) methods that can be applicable to the inspection of FRP-RSC elements from a literature survey of past studies, applications, and research projects. Furthermore, this study evaluates the ability of two of the most commonly used NDT methods, Ground Penetrating Radar (GPR) and Phased Array Ultrasonic (PAU), in detecting FRP bars/strands embedded in concrete elements. GPR and PAU tests were performed on two slab specimens reinforced with GFRP (Glass-FRP) bars, the most commonly used FRP bar, with variations in their depth, size and configuration, and a slab specimen with different types of available FRP reinforcements. The results of this study propose the most applicable methods for detecting FRP and their damage/defects in FRP-RSC elements. This study further investigates the feasibility of two new methods for improving the detectability of embedded FRP bars. By providing the inspection community with more clarity in the application of NDT to FRP, this study offers means for verifying the performance and, therefore, help the proliferation of FRP materials in concrete structures.
{"title":"Applicability of available NDT methods for damage detection in concrete elements reinforced or strengthened with FRP","authors":"P. Malla, S. S. Khedmatgozar Dolati, A. Mehrabi, J. Ortiz Polanco, A. Nanni, K. Dinh","doi":"10.3233/brs-230217","DOIUrl":"https://doi.org/10.3233/brs-230217","url":null,"abstract":"The application of Fiber Reinforced Polymer (FRP) materials in concrete structures has been rising due to their several advantages, including lightweight, high tensile strength, ease of installation, and corrosion resistance. They have been mostly implemented for strengthening and repairing existing structures in the form of an externally bonded system, i.e., sheet, jacket, near surface mounted. Furthermore, they have been recently utilized as internal reinforcement of concrete elements in the form of strands, bars, tendons, etc. Although higher durability and performance are associated with the FRP material in some aspects compared to steel, concerns remain regarding damages and defects in this material, many of which are related to their unique features. Importantly, debonding of FRP materials from a concrete surface or within a concrete element has always been an issue resulting in the premature failure of the structure. To this end, concrete elements strengthened or reinforced with FRP materials has to be inspected periodically to detect potential issues and hence prevent any premature failures. This study first determines all possible or potential damages and anomalies attributed to FRP reinforced/strengthened concrete (FRP-RSC) elements. It then investigates Non-Destructive Testing (NDT) methods that can be applicable to the inspection of FRP-RSC elements from a literature survey of past studies, applications, and research projects. Furthermore, this study evaluates the ability of two of the most commonly used NDT methods, Ground Penetrating Radar (GPR) and Phased Array Ultrasonic (PAU), in detecting FRP bars/strands embedded in concrete elements. GPR and PAU tests were performed on two slab specimens reinforced with GFRP (Glass-FRP) bars, the most commonly used FRP bar, with variations in their depth, size and configuration, and a slab specimen with different types of available FRP reinforcements. The results of this study propose the most applicable methods for detecting FRP and their damage/defects in FRP-RSC elements. This study further investigates the feasibility of two new methods for improving the detectability of embedded FRP bars. By providing the inspection community with more clarity in the application of NDT to FRP, this study offers means for verifying the performance and, therefore, help the proliferation of FRP materials in concrete structures.","PeriodicalId":43279,"journal":{"name":"Bridge Structures","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2023-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138994483","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 minimum flexural reinforcement requirement has been used in the current bridge design specifications to protect the member from brittle failure after the formation of the first flexural cracks. Several variables have been reported to affect this requirement, such as concrete strength, amount of prestressing in the member, and type of cross section. Recently, the Precast/Prestressed Concrete Institute (PCI) developed a new type of beam section (NEXT beam) to accelerate bridge construction and enhance the sustainability of bridges. As a newly developed beam section, no research on the minimum flexural reinforcement has been reported for NEXT beam bridges. This paper aimed to examine the minimum flexural reinforcement requirements in the current AASHTO LRFD Bridge Design Specifications for NEXT beam bridges. A comprehensive parametric study was analytically conducted with various parameters, including bridge section, beam section, concrete strength, and span length. The results from this study showed that the current minimum flexural reinforcement requirements were met for all bridges examined herein; the concrete strength, beam cross section, and span length could affect the levels of safety against brittle failure after first flexural cracks for NEXT beam bridges.
在现行的桥梁设计规范中，最小抗弯配筋要求用于保护构件在形成第一条抗弯裂缝后不会发生脆性破坏。据报道，有几个变量会影响这一要求，如混凝土强度、构件中的预应力量和横截面类型。最近，预制/预应力混凝土协会（PCI）开发了一种新型梁截面（NEXT 梁），以加快桥梁建设速度并提高桥梁的可持续性。作为一种新开发的梁截面，目前还没有关于 NEXT 梁桥最小抗弯配筋的研究报告。本文旨在研究现行 AASHTO LRFD 桥梁设计规范中对 NEXT 梁桥的最小抗弯配筋要求。通过分析各种参数，包括桥梁截面、梁截面、混凝土强度和跨度长度，进行了全面的参数研究。研究结果表明，本文研究的所有桥梁均满足现行的最低抗弯配筋要求；混凝土强度、梁截面和跨度长度会影响 NEXT 梁桥在首次出现抗弯裂缝后的脆性破坏安全等级。
{"title":"Evaluation of minimum flexural reinforcement for precast prestressed concrete NEXT beam bridges","authors":"Jianwei Huang","doi":"10.3233/brs-230218","DOIUrl":"https://doi.org/10.3233/brs-230218","url":null,"abstract":"The minimum flexural reinforcement requirement has been used in the current bridge design specifications to protect the member from brittle failure after the formation of the first flexural cracks. Several variables have been reported to affect this requirement, such as concrete strength, amount of prestressing in the member, and type of cross section. Recently, the Precast/Prestressed Concrete Institute (PCI) developed a new type of beam section (NEXT beam) to accelerate bridge construction and enhance the sustainability of bridges. As a newly developed beam section, no research on the minimum flexural reinforcement has been reported for NEXT beam bridges. This paper aimed to examine the minimum flexural reinforcement requirements in the current AASHTO LRFD Bridge Design Specifications for NEXT beam bridges. A comprehensive parametric study was analytically conducted with various parameters, including bridge section, beam section, concrete strength, and span length. The results from this study showed that the current minimum flexural reinforcement requirements were met for all bridges examined herein; the concrete strength, beam cross section, and span length could affect the levels of safety against brittle failure after first flexural cracks for NEXT beam bridges.","PeriodicalId":43279,"journal":{"name":"Bridge Structures","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138995168","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 stochastic responses of highway bridges to spatial variation of ground motions (SVGM) are analysed in this paper. A model of spatially varying ground motions is used to investigate the relative importance of the incoherency effect, the wave passage effect and the site effects on the stochastic dynamic response of an asymmetrical R.C box girder highway bridge with variable inertia. In this study, the incoherency effect is investigated using two widely used models while the wave-passage effect is incorporated using various wave velocities. Then, the random vibration theory is applied to study the effect of the non-uniform seismic excitations on the bridge structure. The bridge response is evaluated in terms of the mean values of the maximum displacements and the bending moments. Analyses of both stationary and transient response are performed. The results show that the stochastic dynamic responses related to site effects are mostly much greater than those calculated using uniform, delayed and incoherent seismic excitation assumptions. As a result, analytical models used for the stochastic dynamic analysis of long span highway bridges should take into account all the SVGM components, particularly the site-response effects.
{"title":"Quantification of the effects of the spatial variation of ground motions on the seismic response of highway bridges","authors":"Nassira Belkheiri, B. Tiliouine","doi":"10.3233/brs-230205","DOIUrl":"https://doi.org/10.3233/brs-230205","url":null,"abstract":"The stochastic responses of highway bridges to spatial variation of ground motions (SVGM) are analysed in this paper. A model of spatially varying ground motions is used to investigate the relative importance of the incoherency effect, the wave passage effect and the site effects on the stochastic dynamic response of an asymmetrical R.C box girder highway bridge with variable inertia. In this study, the incoherency effect is investigated using two widely used models while the wave-passage effect is incorporated using various wave velocities. Then, the random vibration theory is applied to study the effect of the non-uniform seismic excitations on the bridge structure. The bridge response is evaluated in terms of the mean values of the maximum displacements and the bending moments. Analyses of both stationary and transient response are performed. The results show that the stochastic dynamic responses related to site effects are mostly much greater than those calculated using uniform, delayed and incoherent seismic excitation assumptions. As a result, analytical models used for the stochastic dynamic analysis of long span highway bridges should take into account all the SVGM components, particularly the site-response effects.","PeriodicalId":43279,"journal":{"name":"Bridge Structures","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2023-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48200788","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}
Jie Li, Sida Li, Junfeng Zhang, Yupeng Geng, Da-Yong Yang
In order to clarify the influence of water on the natural vibration of bridge with complex piers, based on a continuous beam with 4-column pier, the numerical analysis model is established. Single column circular pier is taken to discuss the range of waters. Then the influences of water on the natural vibration are analyzed. The research shows that waters reduce the natural frequency. When waters area width is less than 10 m, the natural frequency of the pier decreases. And the first-order longitudinal bending frequency is reduced by 3.36%. When waters area width is more than 10 m, the vibration frequencies tend to be stable gradually. Therefore, the waters 10 m can be regarded as an infinite boundary. The natural frequencies of single column pier and 4-column pier decrease with the increase of water depth. When the water depth is less than 10 m, the changes of natural frequency of the first four orders of single column pier are relatively small, and the changes of 5–10 order natural frequency are large. The maximum effect of the first ten orders is 14.84%. The natural vibration frequency of the bridge decreases gradually with the increase of water depth. The maximum effect of the first five orders is 3.33%.
{"title":"Influence of pier-water interaction on natural vibration characteristics of bridge with complex piers in water","authors":"Jie Li, Sida Li, Junfeng Zhang, Yupeng Geng, Da-Yong Yang","doi":"10.3233/brs-230204","DOIUrl":"https://doi.org/10.3233/brs-230204","url":null,"abstract":"In order to clarify the influence of water on the natural vibration of bridge with complex piers, based on a continuous beam with 4-column pier, the numerical analysis model is established. Single column circular pier is taken to discuss the range of waters. Then the influences of water on the natural vibration are analyzed. The research shows that waters reduce the natural frequency. When waters area width is less than 10 m, the natural frequency of the pier decreases. And the first-order longitudinal bending frequency is reduced by 3.36%. When waters area width is more than 10 m, the vibration frequencies tend to be stable gradually. Therefore, the waters 10 m can be regarded as an infinite boundary. The natural frequencies of single column pier and 4-column pier decrease with the increase of water depth. When the water depth is less than 10 m, the changes of natural frequency of the first four orders of single column pier are relatively small, and the changes of 5–10 order natural frequency are large. The maximum effect of the first ten orders is 14.84%. The natural vibration frequency of the bridge decreases gradually with the increase of water depth. The maximum effect of the first five orders is 3.33%.","PeriodicalId":43279,"journal":{"name":"Bridge Structures","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2023-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47696604","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}
Tao Li, Bori Cong, Maowang Yan, Qingying Li, Xinyuan Zhu
BIM intelligent modeling is used to analyze the safety of the construction scene of prestressed concrete continuous girder bridge, so as to realize the safety management of the bridge construction scene and improve the construction efficiency. The construction safety analysis system is used to analyze the binding data of construction safety, and the data is combined with the self-applicable equilibrium control and the game equilibrium control to build the construction scene safety objective function model. On this basis, combined with the control constraints of the whole life cycle, the statistical analysis regression model is used to build the scene safety analysis model based on BIM. The whole life cycle safety intelligent analysis of the construction scene is realized, and the improved particle swarm optimization algorithm is used to solve the model by adaptive differential evolution, so as to shorten the calculation time of the model. The experimental results show that the safety management performance of the proposed method is high, and the safety management evaluation grade is 285. The identification accuracy of main beam stress change is high. Under the conditions of unbalanced load, combination of unbalanced load and prestress, combination of wind load and prestress and unbalanced load, the safety analysis of upper edge stress and lower edge stress of main beam can be effectively completed, and the construction safety of prestressed concrete continuous beam bridge can be realized.
{"title":"Safety BIM intelligent modeling analysis of prestressed concrete continuous girder bridge construction scene","authors":"Tao Li, Bori Cong, Maowang Yan, Qingying Li, Xinyuan Zhu","doi":"10.3233/brs-230203","DOIUrl":"https://doi.org/10.3233/brs-230203","url":null,"abstract":"BIM intelligent modeling is used to analyze the safety of the construction scene of prestressed concrete continuous girder bridge, so as to realize the safety management of the bridge construction scene and improve the construction efficiency. The construction safety analysis system is used to analyze the binding data of construction safety, and the data is combined with the self-applicable equilibrium control and the game equilibrium control to build the construction scene safety objective function model. On this basis, combined with the control constraints of the whole life cycle, the statistical analysis regression model is used to build the scene safety analysis model based on BIM. The whole life cycle safety intelligent analysis of the construction scene is realized, and the improved particle swarm optimization algorithm is used to solve the model by adaptive differential evolution, so as to shorten the calculation time of the model. The experimental results show that the safety management performance of the proposed method is high, and the safety management evaluation grade is 285. The identification accuracy of main beam stress change is high. Under the conditions of unbalanced load, combination of unbalanced load and prestress, combination of wind load and prestress and unbalanced load, the safety analysis of upper edge stress and lower edge stress of main beam can be effectively completed, and the construction safety of prestressed concrete continuous beam bridge can be realized.","PeriodicalId":43279,"journal":{"name":"Bridge Structures","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2023-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46603068","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}
Over time, owners may face challenges with management of bridges with outdated details. One such detail that is no longer used today is the steel girder shiplap connection. These were originally employed to simplify analysis of continuous girders while also moving joints away from the piers, improving longevity of bridge bearings and substructures. Unfortunately, fatigue issues have appeared in these connections resulting in cracking at critical load-carrying locations. In this project, analysis was performed to investigate connection fatigue and strength and retrofit design verification. Results utilizing non-linear analysis showed that while stresses from ultimate loading could adequately redistribute throughout the web, high stress concentrations were created, exacerbating fatigue. Stress calculations for shiplap web details are not well codified or easily assessed with simple hand calculations, so finite element analysis was utilized. Results showed web fatigue life had been exhausted with more cracking expected at other locations, convincing the owner retrofit was necessary even though the bridge was programmed for replacement.
{"title":"Evaluation and retrofit of steel girder Shiplap connections","authors":"B. Kozy, Jonathan Beckstrom, Tim Armbrecht","doi":"10.3233/brs-230212","DOIUrl":"https://doi.org/10.3233/brs-230212","url":null,"abstract":"Over time, owners may face challenges with management of bridges with outdated details. One such detail that is no longer used today is the steel girder shiplap connection. These were originally employed to simplify analysis of continuous girders while also moving joints away from the piers, improving longevity of bridge bearings and substructures. Unfortunately, fatigue issues have appeared in these connections resulting in cracking at critical load-carrying locations. In this project, analysis was performed to investigate connection fatigue and strength and retrofit design verification. Results utilizing non-linear analysis showed that while stresses from ultimate loading could adequately redistribute throughout the web, high stress concentrations were created, exacerbating fatigue. Stress calculations for shiplap web details are not well codified or easily assessed with simple hand calculations, so finite element analysis was utilized. Results showed web fatigue life had been exhausted with more cracking expected at other locations, convincing the owner retrofit was necessary even though the bridge was programmed for replacement.","PeriodicalId":43279,"journal":{"name":"Bridge Structures","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2023-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44086289","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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