Reinforced concrete (RC) structures are mainly designed to withstand both static and dynamic loads. However, due to the highly nonlinear behavior of RC structures subjected to extreme dynamic loads, these structures have a very complex damage behavior under dynamic impact loading. In fact, current existing methods for damage‐simulation and prediction are generally based on either empirical data, simplified mechanical approaches or complex numerical simulations mainly using the finite element method. In this regard, empirical and semi‐empirical models can be considered to calculate the load‐bearing capacity in a simplified way with only a few input parameters. Hence, using current experimental test data, this paper aims to analyze and assess existing empirical and semi‐analytical approaches that are established in standards and guidelines. Accordingly, a functional relationship in terms of an impact factor is found. Based on the obtained results, different approaches are also developed to describe the resistance to projectile penetration of RC structures as well as the force interaction between projectile and RC structures.
{"title":"Reinforced concrete structures under hard projectile impact: penetration and perforation resistance","authors":"Pascal Distler, Lars Heibges, Hamid Sadegh‐Azar","doi":"10.1002/suco.202300143","DOIUrl":"https://doi.org/10.1002/suco.202300143","url":null,"abstract":"Reinforced concrete (RC) structures are mainly designed to withstand both static and dynamic loads. However, due to the highly nonlinear behavior of RC structures subjected to extreme dynamic loads, these structures have a very complex damage behavior under dynamic impact loading. In fact, current existing methods for damage‐simulation and prediction are generally based on either empirical data, simplified mechanical approaches or complex numerical simulations mainly using the finite element method. In this regard, empirical and semi‐empirical models can be considered to calculate the load‐bearing capacity in a simplified way with only a few input parameters. Hence, using current experimental test data, this paper aims to analyze and assess existing empirical and semi‐analytical approaches that are established in standards and guidelines. Accordingly, a functional relationship in terms of an impact factor is found. Based on the obtained results, different approaches are also developed to describe the resistance to projectile penetration of RC structures as well as the force interaction between projectile and RC structures.","PeriodicalId":21988,"journal":{"name":"Structural Concrete","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142203989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study utilized experimental research to investigate the efficiency of using normal aggregate concrete (NAC) or recycled aggregate concrete (RAC) as a new concrete layer for repairing projectile bullet damage to strengthening reinforced concrete (RC) beams. This study comprised the construction and testing of eight RC beams made of RAC and NAC. They are initially subjected to projectile bullets and after that tested with flexure load to evaluate the effect of using RAC and NAC that was investigated. The findings of test results demonstrate that the repaired specimens with RAC or NAC experienced a higher load capacity than the damaged control specimens. As such, this approach could potentially use to restore RAC or NAC beams were previously damaged by projectile bullets. In addition, the findings of this research indicate that the load capacity of the damaged RC beams that were previously repaired using the NAC layer was higher than the load capacity of the damaged RC beams that were repaired using the RAC layer. The load capacity enhanced significantly of (106%–118%) and (104%–113%), respectively, when NAC and RAC are utilized in repairs. Therefore, using either NAC or RAC concrete is more economical, environmentally friendly, and efficient than demolishing.
{"title":"Effect of using normal concrete or recycled concrete layer on behavior of repaired projectile bullet damaged reinforced concrete beams","authors":"Ala’ Taleb Obaidat","doi":"10.1002/suco.202301054","DOIUrl":"https://doi.org/10.1002/suco.202301054","url":null,"abstract":"This study utilized experimental research to investigate the efficiency of using normal aggregate concrete (NAC) or recycled aggregate concrete (RAC) as a new concrete layer for repairing projectile bullet damage to strengthening reinforced concrete (RC) beams. This study comprised the construction and testing of eight RC beams made of RAC and NAC. They are initially subjected to projectile bullets and after that tested with flexure load to evaluate the effect of using RAC and NAC that was investigated. The findings of test results demonstrate that the repaired specimens with RAC or NAC experienced a higher load capacity than the damaged control specimens. As such, this approach could potentially use to restore RAC or NAC beams were previously damaged by projectile bullets. In addition, the findings of this research indicate that the load capacity of the damaged RC beams that were previously repaired using the NAC layer was higher than the load capacity of the damaged RC beams that were repaired using the RAC layer. The load capacity enhanced significantly of (106%–118%) and (104%–113%), respectively, when NAC and RAC are utilized in repairs. Therefore, using either NAC or RAC concrete is more economical, environmentally friendly, and efficient than demolishing.","PeriodicalId":21988,"journal":{"name":"Structural Concrete","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142203990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Using ultra‐high‐performance fiber‐reinforced concrete (UHPFRC) in profiled slabs, as opposed to normal strength concrete without fibers, has been shown experimentally to significantly increase both the bond between the profiled sheet and the concrete, and the tensile forces across cracked concrete. The consequence of these fiber benefits is to substantially increase the flexural rigidity leading to reduced deflections and also to substantially reduced crack widths leading to improved behavior under serviceability loads and to improved durability. To quantify these benefits so that they can be used in design, a rational partial‐interaction numerical model has been developed that can incorporate the material properties of any type of UHPFRC including time‐effects. This modeling should help in the development of simplified design rules for specific fiber types.
{"title":"Quantifying the serviceability flexural benefits of using UHPFRC in profiled slabs","authors":"S. Chen, P. Visintin, A. B. Sturm, D. J. Oehlers","doi":"10.1002/suco.202300389","DOIUrl":"https://doi.org/10.1002/suco.202300389","url":null,"abstract":"Using ultra‐high‐performance fiber‐reinforced concrete (UHPFRC) in profiled slabs, as opposed to normal strength concrete without fibers, has been shown experimentally to significantly increase both the bond between the profiled sheet and the concrete, and the tensile forces across cracked concrete. The consequence of these fiber benefits is to substantially increase the flexural rigidity leading to reduced deflections and also to substantially reduced crack widths leading to improved behavior under serviceability loads and to improved durability. To quantify these benefits so that they can be used in design, a rational partial‐interaction numerical model has been developed that can incorporate the material properties of any type of UHPFRC including time‐effects. This modeling should help in the development of simplified design rules for specific fiber types.","PeriodicalId":21988,"journal":{"name":"Structural Concrete","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142203991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Martin Lipowczan, Lukáš Novák, David Lehký, Drahomír Novák
The paper portrays a comprehensive computational procedure for determining the global structural resistances of two existing bridges made of I‐73 and KA‐61 precast post‐tensioned concrete girders using advanced statistical assessment methods in combination with nonlinear fracture mechanics‐based finite element method analysis. Although this combination is a powerful tool for realistic modeling of structures, its practical application is still very time consuming. Therefore, a statistical sampling approach for the determination of the structural design resistance is compared to selected efficient semi‐probabilistic methods based on the estimation of coefficient of variation—estimation of coefficient of variation (ECoV) method according to fib Model Code 2010 and improved approach called Eigen ECoV method. Load‐bearing capacity is determined for the ultimate as well as several serviceability limit states. The sensitivity of the input parameters burdened with uncertainties on the response of the structure is quantified using a sensitivity analysis supported by a surrogate model based on polynomial chaos expansion. The paper shows that the applicability of nonlinear modeling with respect to uncertainties is possible when using these ECoV methods and a surrogate model and can be applied in a routine manner. The shortcomings and advantages of all the used safety design/assessment methods are discussed.
本文介绍了一种综合计算程序，该程序采用先进的统计评估方法，结合基于非线性断裂力学的有限元方法分析，确定了两座由 I-73 和 KA-61 预制后张法混凝土梁组成的现有桥梁的整体结构抗力。虽然这种组合是建立真实结构模型的有力工具，但其实际应用仍然非常耗时。因此，我们将用于确定结构设计阻力的统计抽样方法与基于变异系数估算--变异系数估算（ECoV）方法（根据 fib Model Code 2010 和改进方法 Eigen ECoV 方法）的选定高效半概率方法进行了比较。承载能力是根据极限状态和几种适用性极限状态确定的。使用基于多项式混沌扩展的代用模型支持的敏感性分析，量化了输入参数对结构响应的不确定性的敏感性。论文表明，在使用这些 ECoV 方法和代理模型时，可以对不确定性进行非线性建模，并且可以以常规方式应用。文中还讨论了所有使用的安全设计/评估方法的缺点和优点。
{"title":"Nonlinear global design resistance: Case studies of post‐tensioned concrete bridges made of I‐73 and KA‐61 girders","authors":"Martin Lipowczan, Lukáš Novák, David Lehký, Drahomír Novák","doi":"10.1002/suco.202300986","DOIUrl":"https://doi.org/10.1002/suco.202300986","url":null,"abstract":"The paper portrays a comprehensive computational procedure for determining the global structural resistances of two existing bridges made of I‐73 and KA‐61 precast post‐tensioned concrete girders using advanced statistical assessment methods in combination with nonlinear fracture mechanics‐based finite element method analysis. Although this combination is a powerful tool for realistic modeling of structures, its practical application is still very time consuming. Therefore, a statistical sampling approach for the determination of the structural design resistance is compared to selected efficient semi‐probabilistic methods based on the estimation of coefficient of variation—estimation of coefficient of variation (ECoV) method according to <jats:italic>fib</jats:italic> Model Code 2010 and improved approach called Eigen ECoV method. Load‐bearing capacity is determined for the ultimate as well as several serviceability limit states. The sensitivity of the input parameters burdened with uncertainties on the response of the structure is quantified using a sensitivity analysis supported by a surrogate model based on polynomial chaos expansion. The paper shows that the applicability of nonlinear modeling with respect to uncertainties is possible when using these ECoV methods and a surrogate model and can be applied in a routine manner. The shortcomings and advantages of all the used safety design/assessment methods are discussed.","PeriodicalId":21988,"journal":{"name":"Structural Concrete","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142203993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The study examines the early incorporation of reinforced concrete in the architecture of Historicism in Austria–Hungary. Spanning the late 19th to early 20th centuries, the research illuminates the period's stylistic pluralism and the transformative impact of reinforced concrete. The paper examines the integration of reinforced concrete into traditional forms, providing detailed case studies and architectural examples. It navigates through various aspects, including the evolution of reinforced concrete during the historicist period, its adoption in notable structures, and its documentation in contemporary literature. Case studies, such as the Lutheran Church in Battyánd (now Puconci, Slovenia), the Roman Catholic Church in Topolya (now Bačka Topola, Serbia), and the former Synagogue in Český Krumlov, Czechia, showcase the innovative ways reinforced concrete addressed structural challenges while adhering to historicist aesthetics. The research concludes by reflecting on the transformative role of reinforced concrete in challenging the conventions of Historicism, paving the way for modern architectural expressions.
{"title":"Early use of the reinforced concrete in the architecture of the Historicism in Austria–Hungary","authors":"Éva Lovra, Zoltán Bereczki","doi":"10.1002/suco.202400160","DOIUrl":"https://doi.org/10.1002/suco.202400160","url":null,"abstract":"The study examines the early incorporation of reinforced concrete in the architecture of Historicism in Austria–Hungary. Spanning the late 19th to early 20th centuries, the research illuminates the period's stylistic pluralism and the transformative impact of reinforced concrete. The paper examines the integration of reinforced concrete into traditional forms, providing detailed case studies and architectural examples. It navigates through various aspects, including the evolution of reinforced concrete during the historicist period, its adoption in notable structures, and its documentation in contemporary literature. Case studies, such as the Lutheran Church in Battyánd (now Puconci, Slovenia), the Roman Catholic Church in Topolya (now Bačka Topola, Serbia), and the former Synagogue in Český Krumlov, Czechia, showcase the innovative ways reinforced concrete addressed structural challenges while adhering to historicist aesthetics. The research concludes by reflecting on the transformative role of reinforced concrete in challenging the conventions of Historicism, paving the way for modern architectural expressions.","PeriodicalId":21988,"journal":{"name":"Structural Concrete","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142203992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Torkil Veyhe, Henrik Brøner Jørgensen, Søren Gustenhoff Hansen
Within the last decade, a construction‐friendly design principle using flexible wire ropes instead of traditional u‐bars for connecting wall elements has gained popularity. However, anchoring wire ropes in T and L connections remains a complex challenge. Here, the wire ropes stick out of the side of the wall element and are bent in the anchorage zone. This paper presents the findings of an extensive experimental program with 40 specimens, investigating the anchorage capacity of wire ropes in wall elements under these conditions. The study reveals that specially designed reinforcements significantly increase the anchorage capacity, while traditional wall reinforcements have minimal impact. Failure mechanisms primarily involve concrete cone failures, providing valuable insights for construction‐friendly connections. Based on the observed failure mechanism, the paper presents an analytical failure mechanism. The model is based on the upper‐bound theorem of plasticity theory. The model predicts both the capacity and the failure mechanism with satisfactory accuracy.
在过去十年中，使用柔性钢丝绳代替传统 U 型杆来连接墙体构件这一方便施工的设计原则得到了普及。然而，在 T 型和 L 型连接中锚固钢丝绳仍然是一项复杂的挑战。在这种情况下，钢丝绳会从墙体构件的侧面伸出，并在锚固区弯曲。本文介绍了使用 40 个试样进行广泛实验的结果，研究了钢丝绳在这些条件下在墙体构件中的锚固能力。研究结果表明，专门设计的加固件可显著提高锚固能力，而传统墙体加固件的影响则微乎其微。失效机理主要涉及混凝土锥体失效，为施工友好型连接提供了宝贵的见解。根据观察到的失效机理，本文提出了一种分析失效机理。该模型基于塑性理论的上界定理。该模型能准确预测承载能力和失效机理。
{"title":"Anchorage capacity of bent looped wire ropes in precast concrete wall elements for T‐ and L‐ connections","authors":"Torkil Veyhe, Henrik Brøner Jørgensen, Søren Gustenhoff Hansen","doi":"10.1002/suco.202400107","DOIUrl":"https://doi.org/10.1002/suco.202400107","url":null,"abstract":"Within the last decade, a construction‐friendly design principle using flexible wire ropes instead of traditional u‐bars for connecting wall elements has gained popularity. However, anchoring wire ropes in T and L connections remains a complex challenge. Here, the wire ropes stick out of the side of the wall element and are bent in the anchorage zone. This paper presents the findings of an extensive experimental program with 40 specimens, investigating the anchorage capacity of wire ropes in wall elements under these conditions. The study reveals that specially designed reinforcements significantly increase the anchorage capacity, while traditional wall reinforcements have minimal impact. Failure mechanisms primarily involve concrete cone failures, providing valuable insights for construction‐friendly connections. Based on the observed failure mechanism, the paper presents an analytical failure mechanism. The model is based on the upper‐bound theorem of plasticity theory. The model predicts both the capacity and the failure mechanism with satisfactory accuracy.","PeriodicalId":21988,"journal":{"name":"Structural Concrete","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142203994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The understanding of the cyclic performance of reinforced concrete (RC) elements is of vital importance in relation to the extent of the service life of buildings and infrastructures. Steel rebar corrosion plays a major role in this regard because it significantly affects the overall structural integrity, especially under cyclic loads, leading to reduced stiffness and load‐bearing capacity of structural elements. Cyclic condition has the potential to accelerate the corrosion‐induced cracking and spalling, the effectiveness of the bond strength between rebar and concrete, and also the ductility and energy dissipation characteristics of the structure. The primary objective of this study is to investigate the effectiveness of a high‐performance thixotropic repairing cementitious mortar in improving the fatigue behavior of RC elements through a multiscale experimental approach. First, at the material scale of concrete specimens, two different concrete classes together with the repairing one‐component, pre‐blended, thixotropic cementitious mortar, were tested under incremental cyclic condition. Based on the results obtained from material scale, four reinforced concrete beams were exposed to different levels of accelerated corrosion by means of the impressed current technique and, subsequently, repaired by bonding a layer of the thixotropic high‐performance mortar onto the tension side. Finally, beams were tested under incremental cyclic four‐point bending test to investigate the fatigue behavior in terms of crack onset, propagation and energy dissipation. The resulting cyclic properties and cracking behavior of the structural elements were related to the level of corrosion achieved through the accelerated test and the effectiveness of the structural repair mortar was proven. In terms of code compliance, the repairing mortar was able to fulfill the requirements of frequent and quasi‐permanent combination of loads, remaining below all the threshold values provided by the Italian NTC2018 and Eurocode.
{"title":"Flexural behavior of corroded RC beams repaired with high performance cementitious mortar under cyclic loading","authors":"Antonio Mudadu, Andrea Prota, Costantino Menna","doi":"10.1002/suco.202400375","DOIUrl":"https://doi.org/10.1002/suco.202400375","url":null,"abstract":"The understanding of the cyclic performance of reinforced concrete (RC) elements is of vital importance in relation to the extent of the service life of buildings and infrastructures. Steel rebar corrosion plays a major role in this regard because it significantly affects the overall structural integrity, especially under cyclic loads, leading to reduced stiffness and load‐bearing capacity of structural elements. Cyclic condition has the potential to accelerate the corrosion‐induced cracking and spalling, the effectiveness of the bond strength between rebar and concrete, and also the ductility and energy dissipation characteristics of the structure. The primary objective of this study is to investigate the effectiveness of a high‐performance thixotropic repairing cementitious mortar in improving the fatigue behavior of RC elements through a multiscale experimental approach. First, at the material scale of concrete specimens, two different concrete classes together with the repairing one‐component, pre‐blended, thixotropic cementitious mortar, were tested under incremental cyclic condition. Based on the results obtained from material scale, four reinforced concrete beams were exposed to different levels of accelerated corrosion by means of the impressed current technique and, subsequently, repaired by bonding a layer of the thixotropic high‐performance mortar onto the tension side. Finally, beams were tested under incremental cyclic four‐point bending test to investigate the fatigue behavior in terms of crack onset, propagation and energy dissipation. The resulting cyclic properties and cracking behavior of the structural elements were related to the level of corrosion achieved through the accelerated test and the effectiveness of the structural repair mortar was proven. In terms of code compliance, the repairing mortar was able to fulfill the requirements of frequent and quasi‐permanent combination of loads, remaining below all the threshold values provided by the Italian NTC2018 and Eurocode.","PeriodicalId":21988,"journal":{"name":"Structural Concrete","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142203995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tan Wang, Liwei Li, Lijun Dou, Qian Huang, Zhijie Zhou, Yibo Cao, Fan Yang, Zhu Zhu
The paper investigates the behavior of glass‐fiber reinforced polymer (GFRP) reinforced concrete columns with integrated steel spirals (hybrid reinforcement). Six concrete columns were tested under eccentric axial loading, resulting in failure due to bending. Columns with outer steel longitudinal bars experienced steel yielding at peak loads, while those with GFRP outer rebars failed due to concrete crushing. The results revealed that using GFRP as outer longitudinal bars led to peak loads 3–10% lower compared to columns with steel rebars. Inner confinement by steel spirals increased the load‐carrying capacity. Additionally, columns with inner tubular steel exhibited greater strength than those with steel spirals, indicating a slightly enhanced confinement effect. A finite element model was developed to analyze structural behavior, considering both material and geometric nonlinearity. The model's accuracy was validated by comparing predictions with test results. Parametric analysis from the nonlinear FE model showed that eccentricity significantly impacted column load‐carrying capacity. Increasing inner confinement area and the number of inner longitudinal bars improved structural stiffness and load‐carrying capacity. Furthermore, a simplified theoretical method was proposed. Comparison between experimental failure loads and theoretical predictions revealed differences within 20%, indicating satisfactory reliability of the proposed method.
{"title":"Behavior of GFRP reinforced concrete columns confined with inner steel spirals","authors":"Tan Wang, Liwei Li, Lijun Dou, Qian Huang, Zhijie Zhou, Yibo Cao, Fan Yang, Zhu Zhu","doi":"10.1002/suco.202300746","DOIUrl":"https://doi.org/10.1002/suco.202300746","url":null,"abstract":"The paper investigates the behavior of glass‐fiber reinforced polymer (GFRP) reinforced concrete columns with integrated steel spirals (hybrid reinforcement). Six concrete columns were tested under eccentric axial loading, resulting in failure due to bending. Columns with outer steel longitudinal bars experienced steel yielding at peak loads, while those with GFRP outer rebars failed due to concrete crushing. The results revealed that using GFRP as outer longitudinal bars led to peak loads 3–10% lower compared to columns with steel rebars. Inner confinement by steel spirals increased the load‐carrying capacity. Additionally, columns with inner tubular steel exhibited greater strength than those with steel spirals, indicating a slightly enhanced confinement effect. A finite element model was developed to analyze structural behavior, considering both material and geometric nonlinearity. The model's accuracy was validated by comparing predictions with test results. Parametric analysis from the nonlinear FE model showed that eccentricity significantly impacted column load‐carrying capacity. Increasing inner confinement area and the number of inner longitudinal bars improved structural stiffness and load‐carrying capacity. Furthermore, a simplified theoretical method was proposed. Comparison between experimental failure loads and theoretical predictions revealed differences within 20%, indicating satisfactory reliability of the proposed method.","PeriodicalId":21988,"journal":{"name":"Structural Concrete","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142204004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The present study proposes a new technique for retrofitting corroded beam–column joints (BCJs) using high‐strength fiber reinforced concrete (HSFRC) and stirrups replacement. The entire corrosion‐affected concrete was removed and replaced with HSFRC. The corroded reinforcing bars were cleaned and treated to resist the progression of the corrosion mechanism. The severely pitted stirrups were replaced with new stirrups. Four exterior BCJ specimens were tested under seismic loading to determine the effectiveness of the proposed retrofitting scheme. The efficacy of the proposed retrofitting scheme is determined in terms of the hysteresis response, stiffness degradation, cumulative energy dissipation, ductility, and damage index. A significant delay in the fracture of severely pitted reinforcing bars was experienced for the corrosion‐damaged retrofitted specimens compared to the corroded unretrofitted specimen. The cumulative energy dissipation of the corroded unretrofitted and corroded retrofitted specimens was 0.4 and 1.3 times that of the reference specimen, respectively, indicating the effectiveness of the retrofitting strategy, as both specimens had similar corrosion rates. The test results indicated that the proposed retrofitting technique effectively improved the seismic performance of the corrosion‐damaged BCJs.
{"title":"Performance of corroded RC beam–column joints repaired using a hybrid scheme with HSFRC and stirrups replacement","authors":"Shubham Dangwal, Tasham Kumar, Heaven Singh, Raju Sharma","doi":"10.1002/suco.202400654","DOIUrl":"https://doi.org/10.1002/suco.202400654","url":null,"abstract":"The present study proposes a new technique for retrofitting corroded beam–column joints (BCJs) using high‐strength fiber reinforced concrete (HSFRC) and stirrups replacement. The entire corrosion‐affected concrete was removed and replaced with HSFRC. The corroded reinforcing bars were cleaned and treated to resist the progression of the corrosion mechanism. The severely pitted stirrups were replaced with new stirrups. Four exterior BCJ specimens were tested under seismic loading to determine the effectiveness of the proposed retrofitting scheme. The efficacy of the proposed retrofitting scheme is determined in terms of the hysteresis response, stiffness degradation, cumulative energy dissipation, ductility, and damage index. A significant delay in the fracture of severely pitted reinforcing bars was experienced for the corrosion‐damaged retrofitted specimens compared to the corroded unretrofitted specimen. The cumulative energy dissipation of the corroded unretrofitted and corroded retrofitted specimens was 0.4 and 1.3 times that of the reference specimen, respectively, indicating the effectiveness of the retrofitting strategy, as both specimens had similar corrosion rates. The test results indicated that the proposed retrofitting technique effectively improved the seismic performance of the corrosion‐damaged BCJs.","PeriodicalId":21988,"journal":{"name":"Structural Concrete","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142204003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents the experimental results of six full‐scale one‐way reinforced concrete slabs with variations in reinforcement detailing. Test specimens consisted of two reference concrete slabs reinforced fully with glass fiber reinforced polymer (GFRP) rebars or with steel rebars and four hybrid‐reinforced slabs. The variables included the arrangement of rebars, mechanical reinforcing ratio, and the ratio of steel rebar area to GFRP rebar area. The fabricated specimens were subjected to four‐point loading until failure in the strong floor laboratory. Experimental results indicated that hybrid reinforcement enhances stiffness compared to FRP reinforcement and provides a higher load‐bearing capacity than steel reinforcement. Also, it was observed that FRP bars placed as tensile reinforcement, similar in number and diameter size to steel bars placed as compressive reinforcement in a slab result in the highest ultimate capacity. Moreover, it was observed that while the mechanical reinforcing ratio contributes to the overall behavior of hybrid‐reinforced concrete slabs, the ratio of steel rebar area to GFRP rebar area is not considerably effective. Furthermore, image processing was employed to determine the exact crack widths of specimens after failure. Finally, finite element modeling results showed good agreement with the experimental results.
{"title":"Experimental, theoretical and numerical study on flexural behavior of hybrid steel‐GFRP reinforced concrete slabs","authors":"Zeinab Meghdadi, Alireza Khaloo","doi":"10.1002/suco.202301085","DOIUrl":"https://doi.org/10.1002/suco.202301085","url":null,"abstract":"This paper presents the experimental results of six full‐scale one‐way reinforced concrete slabs with variations in reinforcement detailing. Test specimens consisted of two reference concrete slabs reinforced fully with glass fiber reinforced polymer (GFRP) rebars or with steel rebars and four hybrid‐reinforced slabs. The variables included the arrangement of rebars, mechanical reinforcing ratio, and the ratio of steel rebar area to GFRP rebar area. The fabricated specimens were subjected to four‐point loading until failure in the strong floor laboratory. Experimental results indicated that hybrid reinforcement enhances stiffness compared to FRP reinforcement and provides a higher load‐bearing capacity than steel reinforcement. Also, it was observed that FRP bars placed as tensile reinforcement, similar in number and diameter size to steel bars placed as compressive reinforcement in a slab result in the highest ultimate capacity. Moreover, it was observed that while the mechanical reinforcing ratio contributes to the overall behavior of hybrid‐reinforced concrete slabs, the ratio of steel rebar area to GFRP rebar area is not considerably effective. Furthermore, image processing was employed to determine the exact crack widths of specimens after failure. Finally, finite element modeling results showed good agreement with the experimental results.","PeriodicalId":21988,"journal":{"name":"Structural Concrete","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142204005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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