Yan Gao, Yushan Wang, Wenxing Zhu, Haifeng Wang, Huan Liao, Di Xiao, Ziyang Zhang
Reinforced concrete shear walls in multistory buildings often undergo the combined action of vertical and horizontal loads, with their failure primarily attributed to localized damage of the concrete at the bottom of edge elements, leading to premature loss of wall functionality. To enhance the performance of shear walls, this study explores the optimization of shear wall design from the perspective of the stress path within the wall, introducing a diagonally distributed reinforcements in shear walls (referred to as DDR shear walls). To investigate the seismic performance of DDR shear walls, we consider the effects of axial compression ratio, the inclination angle of distributed reinforcing bars, reinforcing bar spacing, and shear span ratio. We design 27 shear wall models with various parameter combinations and employ ABAQUS finite element analysis software to simulate the seismic performance. The simulation results reveal that the inclined distribution of reinforcing bars significantly enhances the seismic performance of shear walls. To achieve optimal structural performance, the inclination angle of reinforcing bars should be adjusted for different floor levels, with higher floors requiring a greater angle and lower floors a smaller one. Additionally, increasing the reinforcing bar spacing and altering the shear span ratio will have varying degrees of impact on the seismic performance of shear walls, necessitating rational design adjustments based on specific circumstances. Furthermore, the application of DDR shear walls in prefabricated construction can be considered to optimize construction processes.
{"title":"Study on seismic performance of reinforced concrete shear wall with diagonally distributed reinforcement","authors":"Yan Gao, Yushan Wang, Wenxing Zhu, Haifeng Wang, Huan Liao, Di Xiao, Ziyang Zhang","doi":"10.1002/suco.202400391","DOIUrl":"https://doi.org/10.1002/suco.202400391","url":null,"abstract":"Reinforced concrete shear walls in multistory buildings often undergo the combined action of vertical and horizontal loads, with their failure primarily attributed to localized damage of the concrete at the bottom of edge elements, leading to premature loss of wall functionality. To enhance the performance of shear walls, this study explores the optimization of shear wall design from the perspective of the stress path within the wall, introducing a diagonally distributed reinforcements in shear walls (referred to as DDR shear walls). To investigate the seismic performance of DDR shear walls, we consider the effects of axial compression ratio, the inclination angle of distributed reinforcing bars, reinforcing bar spacing, and shear span ratio. We design 27 shear wall models with various parameter combinations and employ ABAQUS finite element analysis software to simulate the seismic performance. The simulation results reveal that the inclined distribution of reinforcing bars significantly enhances the seismic performance of shear walls. To achieve optimal structural performance, the inclination angle of reinforcing bars should be adjusted for different floor levels, with higher floors requiring a greater angle and lower floors a smaller one. Additionally, increasing the reinforcing bar spacing and altering the shear span ratio will have varying degrees of impact on the seismic performance of shear walls, necessitating rational design adjustments based on specific circumstances. Furthermore, the application of DDR shear walls in prefabricated construction can be considered to optimize construction processes.","PeriodicalId":21988,"journal":{"name":"Structural Concrete","volume":"41 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141195354","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 aims to experimentally investigate the torsional behavior of acrylic latex polymer and alkali‐resistant glass fiber‐reinforced composite shear walls and load‐bearing sandwich panels. Also, this study was aimed to experimentally examine the changes in the torsional moment capacities, twist angle values, energy dissipation capacities, ductility index, and rigidity of the samples for the presence of the additives added to concrete, size, presence of reinforcement in sandwich panels, and effect of sandwich panels. Within the scope of this work, a control sample, two composite shear walls, and two sandwich panels were produced (1500 × 1200 × 150 mm). While adding 5% acrylic latex to the concrete phase of one of the composite shear wall groups, in the other group, both 5% acrylic latex and 1% alkali‐resistant glass fibers were added to the concrete. While the core structure of the sandwich panel group is reinforced, the other group is produced without reinforcement. A total of 10 samples were loaded out of the plane and a torsional moment is created. As a result of the experiment, the torsional moment, twist angle, and energy dissipation capacities were increased for the samples with acrylic latex and alkali‐resistant glass fiber. While glass fibers increased the ductility index of the test samples, they decreased the stiffness value. Acrylic latex, on the other hand, does not have much effect on the ductility index and stiffness value and increased its energy dissipation capacity. Reinforced sandwich panel samples presented greater torsional moment capacities and stiffnesses compared to composite walls, and less ultimate twist angles and energy dissipation capacities. In addition, although the experimental results of the sandwich panels without reinforcement are lower than the other groups, these also showed load‐bearing capability under the effect of the torsional moment.
{"title":"Torsional behavior of composite shear walls and load‐bearing sandwich panels: An experimental investigation","authors":"Haluk Görkem Alcan, Abdulkadir Cüneyt Aydın","doi":"10.1002/suco.202300764","DOIUrl":"https://doi.org/10.1002/suco.202300764","url":null,"abstract":"This study aims to experimentally investigate the torsional behavior of acrylic latex polymer and alkali‐resistant glass fiber‐reinforced composite shear walls and load‐bearing sandwich panels. Also, this study was aimed to experimentally examine the changes in the torsional moment capacities, twist angle values, energy dissipation capacities, ductility index, and rigidity of the samples for the presence of the additives added to concrete, size, presence of reinforcement in sandwich panels, and effect of sandwich panels. Within the scope of this work, a control sample, two composite shear walls, and two sandwich panels were produced (1500 × 1200 × 150 mm). While adding 5% acrylic latex to the concrete phase of one of the composite shear wall groups, in the other group, both 5% acrylic latex and 1% alkali‐resistant glass fibers were added to the concrete. While the core structure of the sandwich panel group is reinforced, the other group is produced without reinforcement. A total of 10 samples were loaded out of the plane and a torsional moment is created. As a result of the experiment, the torsional moment, twist angle, and energy dissipation capacities were increased for the samples with acrylic latex and alkali‐resistant glass fiber. While glass fibers increased the ductility index of the test samples, they decreased the stiffness value. Acrylic latex, on the other hand, does not have much effect on the ductility index and stiffness value and increased its energy dissipation capacity. Reinforced sandwich panel samples presented greater torsional moment capacities and stiffnesses compared to composite walls, and less ultimate twist angles and energy dissipation capacities. In addition, although the experimental results of the sandwich panels without reinforcement are lower than the other groups, these also showed load‐bearing capability under the effect of the torsional moment.","PeriodicalId":21988,"journal":{"name":"Structural Concrete","volume":"98 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141198387","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 reinforced concrete (RC) shear walls are widely used as the lateral load‐resisting system due to their adequate ductility and great energy dissipation capacity. On the other hand, use of these walls can reduce the size of the beams and columns and also, decreases the lateral displacements. However, presence of the openings in the shear walls alters the behavior of the wall and therefore, the dimensions and position of the opening play a key role in the performance of this structural system. In this study, an RC shear wall with eccentric opening was verified using ABAQUS software. This model, which is called the reference model, a wall and a pier have been created according to aspect ratios given by ACI318‐14. This model was retrofitted with the steel plates arranged in various patterns and effect of each pattern on the system's performance was investigated and the best one was selected. The best steel plate arrangement increased the ultimate strength, maximum strength, cracking strength, and energy dissipation capacity by 127.3%, 13.42%, 22.53%, and 16.8%, respectively. To practically use this retrofit technique, three low, mid, and high‐rise buildings designed based on the old and new versions of the Iranian Code of Practice for Seismic Resistant Design of Buildings (Standard 2800) were upgraded with this technique and their performance was evaluated and performance of the substandard and standard buildings were compared with each other. The research results showed the ST52 steel plates do not considerably increase the maximum and cracking strength and could enhance the ultimate strength insignificantly. By retrofitting the edges of the openings by the diagonal steel plates and preventing spread of the cracks at the edges and corners, satisfactory results could be attained. Simultaneous use of the vertical and horizontal plates is an effective solution to increase the flexural and shear capacity of the structure.
{"title":"Cyclic behavior of the reinforced concrete shear walls with opening retrofitted with steel plate","authors":"Fatemeh Abdoos, Majid Gholhaki, Ali Kheyroddin","doi":"10.1002/suco.202300285","DOIUrl":"https://doi.org/10.1002/suco.202300285","url":null,"abstract":"The reinforced concrete (RC) shear walls are widely used as the lateral load‐resisting system due to their adequate ductility and great energy dissipation capacity. On the other hand, use of these walls can reduce the size of the beams and columns and also, decreases the lateral displacements. However, presence of the openings in the shear walls alters the behavior of the wall and therefore, the dimensions and position of the opening play a key role in the performance of this structural system. In this study, an RC shear wall with eccentric opening was verified using ABAQUS software. This model, which is called the reference model, a wall and a pier have been created according to aspect ratios given by ACI318‐14. This model was retrofitted with the steel plates arranged in various patterns and effect of each pattern on the system's performance was investigated and the best one was selected. The best steel plate arrangement increased the ultimate strength, maximum strength, cracking strength, and energy dissipation capacity by 127.3%, 13.42%, 22.53%, and 16.8%, respectively. To practically use this retrofit technique, three low, mid, and high‐rise buildings designed based on the old and new versions of the Iranian Code of Practice for Seismic Resistant Design of Buildings (Standard 2800) were upgraded with this technique and their performance was evaluated and performance of the substandard and standard buildings were compared with each other. The research results showed the ST52 steel plates do not considerably increase the maximum and cracking strength and could enhance the ultimate strength insignificantly. By retrofitting the edges of the openings by the diagonal steel plates and preventing spread of the cracks at the edges and corners, satisfactory results could be attained. Simultaneous use of the vertical and horizontal plates is an effective solution to increase the flexural and shear capacity of the structure.","PeriodicalId":21988,"journal":{"name":"Structural Concrete","volume":"24 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141195253","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}
Precast prestressed hollow core (HC) floors are widely used in various applications within the construction sector. Such floors are usually designed as single, simply supported elements, although it is known that individual elements forming the floor interact with each other. This article presents the state of the art regarding load redistribution in HC floors in the light of experimental data, current analytical models and code provisions. While this phenomenon is widely known and recognized, only sparse, and often poorly documented experimental data are available, which represent the basis for the assessment and calibration of analytical models. Moreover, even though the available models and code provisions share similar assumptions, their outcomes are in some cases conflicting. Having recognized the existing knowledge gap, the authors outline future perspectives for the development of consistent analytical and numerical approaches supplemented by new experimental data.
预制预应力空心楼板（HC）广泛应用于建筑领域的各种应用中。此类楼板通常被设计为单个、简单支撑的构件，但众所周知，构成楼板的各个构件是相互影响的。本文根据实验数据、当前的分析模型和规范规定，介绍了有关 HC 楼板荷载再分布的最新技术。虽然这种现象已广为人知并得到认可，但目前仅有稀少的实验数据，而且往往记录不全，而这些数据是评估和校准分析模型的基础。此外，尽管现有模型和规范条款的假设条件相似，但其结果在某些情况下却相互矛盾。在认识到现有的知识差距之后，作者概述了以新的实验数据为补充，开发一致的分析和数值方法的未来前景。
{"title":"Vertical load distribution in precast hollow core floors: State of the art and future perspectives","authors":"Miłosz Jeziorski, Wit Derkowski, Elena Michelini","doi":"10.1002/suco.202301150","DOIUrl":"https://doi.org/10.1002/suco.202301150","url":null,"abstract":"Precast prestressed hollow core (HC) floors are widely used in various applications within the construction sector. Such floors are usually designed as single, simply supported elements, although it is known that individual elements forming the floor interact with each other. This article presents the state of the art regarding load redistribution in HC floors in the light of experimental data, current analytical models and code provisions. While this phenomenon is widely known and recognized, only sparse, and often poorly documented experimental data are available, which represent the basis for the assessment and calibration of analytical models. Moreover, even though the available models and code provisions share similar assumptions, their outcomes are in some cases conflicting. Having recognized the existing knowledge gap, the authors outline future perspectives for the development of consistent analytical and numerical approaches supplemented by new experimental data.","PeriodicalId":21988,"journal":{"name":"Structural Concrete","volume":"10 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141195255","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 article aims to address the issues of high curing temperatures and thermal damage in the production of prefabricated concrete components for high‐speed railways in high‐altitude and high‐latitude cold regions of China. Various steam‐curing processes for concrete are designed to optimize the high‐quality preparation process of steam‐cured concrete prefabricated components in cold environments. With the goal of controlling the residual expansion deformation and considering the overall impact of curing process on the mechanics, durability, and interface transition zone of steam‐cured concrete, the main conclusions obtained in this study are as follows. Within a pre‐curing time of 3–6 h, when the curing temperature is maintained at 45–60°C, the final residual expansion deformation can be controlled below 300 με. The compressive strength, dynamic elastic modulus, peak stress, water absorption and Chloride ion resistance of steam‐cured concrete show the great improvement under above curing processes. Curing at 80°C should be actively avoided, and it is recommended to adopt a 6 h pre‐curing time with a maximum curing temperature of 45°C, especially for cold regions in China. This study can serve as a valuable reference and provide support for the preparation of prefabricated concrete components in Chinese high‐altitude and high‐latitude areas.
本文旨在解决中国高海拔和高纬度寒冷地区高速铁路混凝土预制构件生产过程中的高养护温度和热损伤问题。为优化寒冷环境下蒸汽养护混凝土预制构件的高质量制备工艺，设计了多种混凝土蒸汽养护工艺。以控制残余膨胀变形为目标，综合考虑养护工艺对蒸养混凝土力学、耐久性和界面过渡区的影响，本研究得出以下主要结论。在预养护时间为 3-6 小时内，当养护温度保持在 45-60°C 时，最终残余膨胀变形可控制在 300 με 以下。在上述养护过程中，蒸养混凝土的抗压强度、动弹性模量、峰值应力、吸水率和抗氯离子能力都有很大提高。应积极避免 80°C 的养护温度，建议采用 6 h 的预养护时间和 45°C 的最高养护温度，尤其适用于中国寒冷地区。本研究可为中国高海拔和高纬度地区预制混凝土构件的制备提供有价值的参考和支持。
{"title":"Optimization of steam curing process for Chinese Western and Northeast regions' high‐speed railway concrete prefabricated components","authors":"Yu Xiang, Peilun Duan, Jilin Wang, Guokang Jiang, Zuhao Hu, Qiyuan Xiao, Xiaohui Zeng","doi":"10.1002/suco.202400079","DOIUrl":"https://doi.org/10.1002/suco.202400079","url":null,"abstract":"This article aims to address the issues of high curing temperatures and thermal damage in the production of prefabricated concrete components for high‐speed railways in high‐altitude and high‐latitude cold regions of China. Various steam‐curing processes for concrete are designed to optimize the high‐quality preparation process of steam‐cured concrete prefabricated components in cold environments. With the goal of controlling the residual expansion deformation and considering the overall impact of curing process on the mechanics, durability, and interface transition zone of steam‐cured concrete, the main conclusions obtained in this study are as follows. Within a pre‐curing time of 3–6 h, when the curing temperature is maintained at 45–60°C, the final residual expansion deformation can be controlled below 300 με. The compressive strength, dynamic elastic modulus, peak stress, water absorption and Chloride ion resistance of steam‐cured concrete show the great improvement under above curing processes. Curing at 80°C should be actively avoided, and it is recommended to adopt a 6 h pre‐curing time with a maximum curing temperature of 45°C, especially for cold regions in China. This study can serve as a valuable reference and provide support for the preparation of prefabricated concrete components in Chinese high‐altitude and high‐latitude areas.","PeriodicalId":21988,"journal":{"name":"Structural Concrete","volume":"59 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141195338","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}
Possible discontinuities in the subsurface have a major impact on the load‐bearing behavior of post‐installed fastenings. For concrete, the behavior of post‐installed anchors and thus their design can be clearly addressed as concrete is assumed as a homogeneous fastening substrate. This is valid except, for example, in the area of building joints and at joints of precast concrete elements, where the formation of structural joints inevitably occurs and which basically correspond to a separation surface. In contrast, rock mass is characterized by the rock type, but is generally also significantly influenced by its discontinuities. These play a decisive role concerning rock mass stability and show a great impact on the load‐bearing capacity of rock, especially for fasteners with a shallow embedment depth. It is to be assumed that the same also applies to separating surfaces in concrete. Furthermore, the question arises as to the non‐destructive preliminary detectability of such weak zones. For carrying out a comparative study under controlled conditions, artificial interfaces of different geometries were generated in concrete in laboratory tests by inserting PTFE layers at different positions of the test member. Pull‐out tests of post‐installed fastening systems were carried out in their vicinity to determine the load transfer as well as the failure mode. It could be shown that discontinuities have a negative effect on pull‐out loads not only in the rock mass, but also in concrete. However, detection of these by means of a rebound hammer was only possible in the rock mass.
{"title":"Fastening in concrete vs. rock mass—Comparative determination of pull‐out loads for artificially created discontinuities in concrete","authors":"O. Zeman, K. Voit, S. Lamplmair‐Irsigler","doi":"10.1002/suco.202400059","DOIUrl":"https://doi.org/10.1002/suco.202400059","url":null,"abstract":"Possible discontinuities in the subsurface have a major impact on the load‐bearing behavior of post‐installed fastenings. For concrete, the behavior of post‐installed anchors and thus their design can be clearly addressed as concrete is assumed as a homogeneous fastening substrate. This is valid except, for example, in the area of building joints and at joints of precast concrete elements, where the formation of structural joints inevitably occurs and which basically correspond to a separation surface. In contrast, rock mass is characterized by the rock type, but is generally also significantly influenced by its discontinuities. These play a decisive role concerning rock mass stability and show a great impact on the load‐bearing capacity of rock, especially for fasteners with a shallow embedment depth. It is to be assumed that the same also applies to separating surfaces in concrete. Furthermore, the question arises as to the non‐destructive preliminary detectability of such weak zones. For carrying out a comparative study under controlled conditions, artificial interfaces of different geometries were generated in concrete in laboratory tests by inserting PTFE layers at different positions of the test member. Pull‐out tests of post‐installed fastening systems were carried out in their vicinity to determine the load transfer as well as the failure mode. It could be shown that discontinuities have a negative effect on pull‐out loads not only in the rock mass, but also in concrete. However, detection of these by means of a rebound hammer was only possible in the rock mass.","PeriodicalId":21988,"journal":{"name":"Structural Concrete","volume":"41 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141195248","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}
Muhammad Hassam, Lanhui Guo, Muhammad Tahir, Muhammad Atasham ul haq, Rizwan Jamil
Special‐shaped concrete‐filled steel tubes (CFSTs) have been used in modern structures like high‐rise commercial and residential buildings due to their superior structural performance compared to steel and reinforced concrete members. Various shapes of special‐shaped CFSTs might be necessary to meet architectural and aesthetic needs. Cross‐shaped CFSTs could be used where two orthogonal walls cross in high‐rise buildings. However, at present, the research on the compressive performance of cross‐shaped CFSTs is limited, consequently, the unavailability of design guidelines and design‐oriented strength prediction models. Therefore, in this study, a finite element (FE) model of cross‐shaped CFSTs was developed following the past experimental data, and the model's accuracy was verified by the failure modes and load–strain curves of specimens. Sensitivity analysis was performed for some parameters of the concrete damaged plasticity model besides imperfections and residual stress. The parametric analysis was conducted considering various study parameters such as the width‐to‐thickness ratio, width‐to‐depth ratio, and steel and concrete strengths. The compressive strength of cross‐shaped CFSTs was predicted by different design codes and available design formulas, which gave unsatisfactory results necessitating the development of new strength prediction models. Finally, a new design formula was developed by performing a linear regression of FE and test results. The proposed formula predicted the strength of cross‐shaped CFSTs with great accuracy and can be used for design purposes.
{"title":"Prediction of compressive strength of cross‐shaped stub CFSTs under axial loading: Numerical and analytical study","authors":"Muhammad Hassam, Lanhui Guo, Muhammad Tahir, Muhammad Atasham ul haq, Rizwan Jamil","doi":"10.1002/suco.202301048","DOIUrl":"https://doi.org/10.1002/suco.202301048","url":null,"abstract":"Special‐shaped concrete‐filled steel tubes (CFSTs) have been used in modern structures like high‐rise commercial and residential buildings due to their superior structural performance compared to steel and reinforced concrete members. Various shapes of special‐shaped CFSTs might be necessary to meet architectural and aesthetic needs. Cross‐shaped CFSTs could be used where two orthogonal walls cross in high‐rise buildings. However, at present, the research on the compressive performance of cross‐shaped CFSTs is limited, consequently, the unavailability of design guidelines and design‐oriented strength prediction models. Therefore, in this study, a finite element (FE) model of cross‐shaped CFSTs was developed following the past experimental data, and the model's accuracy was verified by the failure modes and load–strain curves of specimens. Sensitivity analysis was performed for some parameters of the concrete damaged plasticity model besides imperfections and residual stress. The parametric analysis was conducted considering various study parameters such as the width‐to‐thickness ratio, width‐to‐depth ratio, and steel and concrete strengths. The compressive strength of cross‐shaped CFSTs was predicted by different design codes and available design formulas, which gave unsatisfactory results necessitating the development of new strength prediction models. Finally, a new design formula was developed by performing a linear regression of FE and test results. The proposed formula predicted the strength of cross‐shaped CFSTs with great accuracy and can be used for design purposes.","PeriodicalId":21988,"journal":{"name":"Structural Concrete","volume":"72 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141166704","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 Annex D of the future EC2 draft gives guidance on the evaluation of early‐age cracking of large structures due to restraint. In case of restrained conditions, compressive stresses are firstly generated in massive structures due to temperature increase, then tensile stresses are generated due to temperature decrease and shrinkage. Due to these tensile stresses, there is a risk of cracking which may be evaluated by the simplified method in Annex D. This method is currently verified against laboratory tests performed in the temperature‐stress testing machine and field cases on restrained concrete elements. The laboratory verification consisted of five approaches to consider different available input (modeled, assumed, or measured). The field investigation focused on the relation between the calculated cracking risk and the observed damage. The results show that the method has very good accuracy and captures with reasonable simplicity the mechanisms and the relations between the parameters involved.
未来的 EC2 草案附件 D 为评估大型结构因约束而产生的早期开裂提供了指导。在约束条件下，大型结构首先会因温度升高而产生压应力，然后会因温度降低和收缩而产生拉应力。由于这些拉应力，存在开裂的风险，可采用附件 D 中的简化方法进行评估。目前，该方法已通过温度应力试验机进行的实验室试验和受约束混凝土构件的现场案例进行了验证。实验室验证包括五种方法，以考虑不同的可用输入（模型、假设或测量）。现场调查的重点是计算的开裂风险与观察到的损坏之间的关系。结果表明，该方法具有很高的准确性，并以合理的简单性捕捉到了相关参数之间的机理和关系。
{"title":"Early‐age cracking due to restraint: Laboratory and field investigations on the predictive capacity of the simplified method in Annex D of the future EC2","authors":"Antonia Menga, Jean‐Michel Torrenti, Terje Kanstad, Anja Birgitta Estensen Klausen","doi":"10.1002/suco.202400173","DOIUrl":"https://doi.org/10.1002/suco.202400173","url":null,"abstract":"The Annex D of the future EC2 draft gives guidance on the evaluation of early‐age cracking of large structures due to restraint. In case of restrained conditions, compressive stresses are firstly generated in massive structures due to temperature increase, then tensile stresses are generated due to temperature decrease and shrinkage. Due to these tensile stresses, there is a risk of cracking which may be evaluated by the simplified method in Annex D. This method is currently verified against laboratory tests performed in the temperature‐stress testing machine and field cases on restrained concrete elements. The laboratory verification consisted of five approaches to consider different available input (modeled, assumed, or measured). The field investigation focused on the relation between the calculated cracking risk and the observed damage. The results show that the method has very good accuracy and captures with reasonable simplicity the mechanisms and the relations between the parameters involved.","PeriodicalId":21988,"journal":{"name":"Structural Concrete","volume":"23 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141166783","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 reported the axial (concentric and eccentric) and bending (four‐point bending) loadings behavior of glass fiber‐reinforced polymer (GFRP) bar‐reinforced hollow‐core polypropylene fiber concrete (HC‐GFRP‐PFC) columns. The confinement effect of HC‐GFRP‐PFC columns with different center‐to‐center (c/c) spacing of GFRP spirals was also investigated. Twelve hollow‐core circular specimens with an outer diameter of 214 mm and an inner (circular hole) diameter of 56 mm were experimentally investigated. Four reference specimens were cast with nonfibrous (normal) concrete, whereas the remaining eight specimens were cast with polypropylene fiber (0.15% by volume of concrete) concrete. It was found that, with a similar ratio of reinforcement, the HC‐GFRP‐PFC specimens gained 2%–4% higher maximum load (PMaximum) and 9%–19% higher ductility (μ) than the GFRP bar‐reinforced hollow‐core nonfibrous concrete (HC‐GFRP‐NFC) specimens under concentric axial loading and four‐point bending. The HC‐GFRP‐PFC specimens with a 30 mm c/c spacing of the GFRP spiral gained 6%–36% higher PMaximum and 4%–59% higher μ than the HC‐GFRP‐PFC specimens with a 60 mm c/c spacing of the GFRP spirals under different loading conditions.
{"title":"Axial and bending behavior of GFRP bar‐reinforced hollow‐core polypropylene fiber concrete columns","authors":"Habil Ahmad, M. Neaz Sheikh, Muhammad N. S. Hadi","doi":"10.1002/suco.202200921","DOIUrl":"https://doi.org/10.1002/suco.202200921","url":null,"abstract":"This study reported the axial (concentric and eccentric) and bending (four‐point bending) loadings behavior of glass fiber‐reinforced polymer (GFRP) bar‐reinforced hollow‐core polypropylene fiber concrete (HC‐GFRP‐PFC) columns. The confinement effect of HC‐GFRP‐PFC columns with different center‐to‐center (c/c) spacing of GFRP spirals was also investigated. Twelve hollow‐core circular specimens with an outer diameter of 214 mm and an inner (circular hole) diameter of 56 mm were experimentally investigated. Four reference specimens were cast with nonfibrous (normal) concrete, whereas the remaining eight specimens were cast with polypropylene fiber (0.15% by volume of concrete) concrete. It was found that, with a similar ratio of reinforcement, the HC‐GFRP‐PFC specimens gained 2%–4% higher maximum load (<jats:italic>P</jats:italic><jats:sub>Maximum</jats:sub>) and 9%–19% higher ductility (μ) than the GFRP bar‐reinforced hollow‐core nonfibrous concrete (HC‐GFRP‐NFC) specimens under concentric axial loading and four‐point bending. The HC‐GFRP‐PFC specimens with a 30 mm c/c spacing of the GFRP spiral gained 6%–36% higher <jats:italic>P</jats:italic><jats:sub>Maximum</jats:sub> and 4%–59% higher μ than the HC‐GFRP‐PFC specimens with a 60 mm c/c spacing of the GFRP spirals under different loading conditions.","PeriodicalId":21988,"journal":{"name":"Structural Concrete","volume":"5 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141147436","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}
Michael J. McGinnis, Michael V. Gangone, Alejandro Nogales, Lizeth Marisol Gomez‐Santana, Brad Weldon, Adam Reihl, Nikola Tošić, Yahya Kurama
Although it has been shown that using recycled concrete aggregate in new structural concrete is economical and sustainable, the use of this material for such applications is still not widespread. One of the reasons is that manufacturers, designers, engineers, owners, and other market players are not familiar with specifying and utilizing this material—although standards are starting to incorporate provisions for recycled aggregate concrete, successful, practical example projects are needed. The current paper describes the results of a partnership between universities and a precast concrete manufacturer of hollow core slabs. Seven hollow core slabs with volumetric replacement ratios of natural aggregate with recycled aggregate from 0% to 60% were tested to failure in both bending and shear, and then undamaged portions of the slabs were subjected to punching shear until failure. The results showed only mild differences in strength, with different replacement percentages of recycled aggregate under the various loading scenarios. Numerical simulations performed in Abaqus demonstrated the feasibility of analyzing recycled aggregate concrete structural elements and provided important insights into their behavior.
{"title":"Experimental and numerical investigation of the bending, shear, and punching shear behavior of recycled aggregate concrete precast/prestressed hollow core slabs","authors":"Michael J. McGinnis, Michael V. Gangone, Alejandro Nogales, Lizeth Marisol Gomez‐Santana, Brad Weldon, Adam Reihl, Nikola Tošić, Yahya Kurama","doi":"10.1002/suco.202400008","DOIUrl":"https://doi.org/10.1002/suco.202400008","url":null,"abstract":"Although it has been shown that using recycled concrete aggregate in new structural concrete is economical and sustainable, the use of this material for such applications is still not widespread. One of the reasons is that manufacturers, designers, engineers, owners, and other market players are not familiar with specifying and utilizing this material—although standards are starting to incorporate provisions for recycled aggregate concrete, successful, practical example projects are needed. The current paper describes the results of a partnership between universities and a precast concrete manufacturer of hollow core slabs. Seven hollow core slabs with volumetric replacement ratios of natural aggregate with recycled aggregate from 0% to 60% were tested to failure in both bending and shear, and then undamaged portions of the slabs were subjected to punching shear until failure. The results showed only mild differences in strength, with different replacement percentages of recycled aggregate under the various loading scenarios. Numerical simulations performed in Abaqus demonstrated the feasibility of analyzing recycled aggregate concrete structural elements and provided important insights into their behavior.","PeriodicalId":21988,"journal":{"name":"Structural Concrete","volume":"50 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141147555","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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