Talip Cakmak, Ilker Ustabas, Zafer Kurt, Ali Gurbuz
Geopolymer mortars, which cause less CO2 emissions than concrete and its raw material cement, are an innovative, environmentally friendly and sustainable building material. Geopolymers are formed by activating silica and alumina materials with alkaline activators. In this study, a geopolymer mortar containing obsidian (OB), also known as volcanic glass, which is free, and silica fume (SF), which is the waste material of the silicon and ferrosilicon industry, was investigated. The behavior of OB‐based geopolymer mortars under different curing times ranging from 2 to 120 h and different thermal treatment temperatures such as 90, 150, and 200°C were examined. The effectiveness of OB and SF on the physical features, compressive strength (CS), and micro‐structural of the geopolymers were characterized. Results demonstrated that the peak CSs were acquired in 96 h at 90 and 150°C heat treatment temperatures, while the highest CSs were acquired in 72 h for specimens subjected to 200°C heat treatment. Reduces in CSs were detected when the curing time exceeded the ideal limit. OB‐based geopolymer was found to be stable with SF and there was a linear relationship between SF substitution ratio and CS. The density of the mortar pieces decreased with increasing thermal curing hours. Devolving on the thermal temperature and curing time, the microstructures became more compact and microvoids and cracks decreased. It was observed that SF substitution reduced the total pore size of the geopolymers and allowed the pore structure size to be reduced. The results obtained from the study are expected to encourage the utilize of industrial wastes and new binders in the manufacture of geopolymers.
土工聚合物砂浆比混凝土及其原材料水泥的二氧化碳排放量更少，是一种创新、环保和可持续的建筑材料。土工聚合物是用碱性活化剂活化二氧化硅和氧化铝材料而形成的。本研究调查了一种土工聚合物砂浆，其中含有游离的黑曜石（OB）（又称火山玻璃）和硅灰（SF）（硅和硅铁工业的废料）。研究了基于 OB 的土工聚合物砂浆在 2 至 120 小时不同固化时间和 90、150 和 200°C 不同热处理温度下的行为。研究了 OB 和 SF 对土工聚合物的物理特性、抗压强度（CS）和微观结构的影响。结果表明，在 90 和 150°C 热处理温度下，96 小时内获得的 CS 值达到峰值，而在 200°C 热处理温度下，72 小时内获得的 CS 值最高。当固化时间超过理想极限时，CSs 会降低。研究发现，OB 基土工聚合物与 SF 具有良好的稳定性，SF 替代率与 CS 之间呈线性关系。砂浆的密度随着热固化时间的增加而降低。随着热温度和固化时间的变化，微观结构变得更加致密，微空洞和裂缝减少。据观察，SF 替代降低了土工聚合物的总孔径，并使孔隙结构尺寸减小。这项研究的结果有望鼓励在制造土工聚合物时利用工业废料和新型粘合剂。
{"title":"The importance of early strength in structural applications: Obsidian‐based geopolymer mortars and silica fume substitution study","authors":"Talip Cakmak, Ilker Ustabas, Zafer Kurt, Ali Gurbuz","doi":"10.1002/suco.202400726","DOIUrl":"https://doi.org/10.1002/suco.202400726","url":null,"abstract":"Geopolymer mortars, which cause less CO<jats:sub>2</jats:sub> emissions than concrete and its raw material cement, are an innovative, environmentally friendly and sustainable building material. Geopolymers are formed by activating silica and alumina materials with alkaline activators. In this study, a geopolymer mortar containing obsidian (OB), also known as volcanic glass, which is free, and silica fume (SF), which is the waste material of the silicon and ferrosilicon industry, was investigated. The behavior of OB‐based geopolymer mortars under different curing times ranging from 2 to 120 h and different thermal treatment temperatures such as 90, 150, and 200°C were examined. The effectiveness of OB and SF on the physical features, compressive strength (CS), and micro‐structural of the geopolymers were characterized. Results demonstrated that the peak CSs were acquired in 96 h at 90 and 150°C heat treatment temperatures, while the highest CSs were acquired in 72 h for specimens subjected to 200°C heat treatment. Reduces in CSs were detected when the curing time exceeded the ideal limit. OB‐based geopolymer was found to be stable with SF and there was a linear relationship between SF substitution ratio and CS. The density of the mortar pieces decreased with increasing thermal curing hours. Devolving on the thermal temperature and curing time, the microstructures became more compact and microvoids and cracks decreased. It was observed that SF substitution reduced the total pore size of the geopolymers and allowed the pore structure size to be reduced. The results obtained from the study are expected to encourage the utilize of industrial wastes and new binders in the manufacture of geopolymers.","PeriodicalId":21988,"journal":{"name":"Structural Concrete","volume":"70 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141882554","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}
Xu Binlin, Tian Zhongchu, Shen Xiaoping, Bai Wenguang
During the cantilever casting process of reinforced concrete arch bridges with cantilever cast‐in‐situ method, it is difficult to select representative training samples for reliability analysis due to its complex structural system. Many random variables and large computational sample size, this paper proposes to solve the reliability indexes based on the combination of the improved sparrow search algorithm (LGSSA) and the support vector regression (SVR) method. Firstly, random variables are selected according to the actual situation of the bridge structure. Then representative training samples are designed to be substituted into the finite element model through the homogeneous method. The resultant data samples are used to fit the functional function by the support vector regression. Then combined with the penalized function method to transform the nonlinear optimization into the problem of solving the extreme value of the function. Based on the improved SSA to solve the extreme value of the final function. Finally the reliability index of the structure is obtained. With the background of reinforced concrete arch bridge of 200 m, the method is used to analyze the reliability of its buckling cable stress, arch stress, buckling tower deviation and structural system reliability during the cantilever casting process. The results show that the overall structural reliability of the arch ring during cantilever casting is 3.502–3.608. The indexes of buckling cable stress reliability are 3.806–6.784. The indexes of arch ring stress reliability are 4.379–7.562, and the indexes of buckling tower deflection reliability are 3.608–8.123.
{"title":"Reliability evaluation of reinforced concrete arch bridges during construction based on LGSSA‐SVR hybrid algorithm","authors":"Xu Binlin, Tian Zhongchu, Shen Xiaoping, Bai Wenguang","doi":"10.1002/suco.202400166","DOIUrl":"https://doi.org/10.1002/suco.202400166","url":null,"abstract":"During the cantilever casting process of reinforced concrete arch bridges with cantilever cast‐in‐situ method, it is difficult to select representative training samples for reliability analysis due to its complex structural system. Many random variables and large computational sample size, this paper proposes to solve the reliability indexes based on the combination of the improved sparrow search algorithm (LGSSA) and the support vector regression (SVR) method. Firstly, random variables are selected according to the actual situation of the bridge structure. Then representative training samples are designed to be substituted into the finite element model through the homogeneous method. The resultant data samples are used to fit the functional function by the support vector regression. Then combined with the penalized function method to transform the nonlinear optimization into the problem of solving the extreme value of the function. Based on the improved SSA to solve the extreme value of the final function. Finally the reliability index of the structure is obtained. With the background of reinforced concrete arch bridge of 200 m, the method is used to analyze the reliability of its buckling cable stress, arch stress, buckling tower deviation and structural system reliability during the cantilever casting process. The results show that the overall structural reliability of the arch ring during cantilever casting is 3.502–3.608. The indexes of buckling cable stress reliability are 3.806–6.784. The indexes of arch ring stress reliability are 4.379–7.562, and the indexes of buckling tower deflection reliability are 3.608–8.123.","PeriodicalId":21988,"journal":{"name":"Structural Concrete","volume":"132 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141868665","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}
Joaquim A. O. Barros, Beatriz Sanz, Marcílio Filho, Petr Kabele, Rena C. Yu, Günther Meschke, Jaime Planas, Vitor Cunha, Gerrit E. Neu, Antonio Caggiano, Ventura Gouveia, Nilüfer Ozyurt, Elisa Poveda, Ab van den Bos, Jan Červenka, Erez Gal, Pierre Rossi, Daniel Dias‐da‐Costa, Peter K. Juhasz, David Cendón, Gonzalo Ruiz
This paper describes the 3rd Blind Simulation Competition (BSC) organized by the fib WP 2.4.1 which aims to assess the predictive performance of models based on the finite element method (FEM) for analysis and design of fiber reinforced concrete (FRC) structures submitted to loading and support conditions that promote punching failure mode. Fiber reinforcement is used in an attempt to eliminate conventional punching reinforcement and provide technical and economic advantages. The two tested real‐size prototypes represent a column‐slab interior region of an elevated steel‐fiber reinforced concrete (E‐SFRC) slab where anti‐progressive collapse reinforcement is disposed in the alignment of columns/piles. Despite a punching failure surface being formed in both experimentally tested prototypes at the rupture stage, fiber reinforcement was able to mobilize the yield capacity of the conventional flexural reinforcement, providing high deformation capacity, and ductility to the prototypes. The average post‐peak load‐carrying capacity of the tested prototypes at a deflection seven times higher than the deflection at yield initiation of the conventional reinforcement was still 90% of the average peak load. Regarding the BSC, a total of 26 proposals were received and involved 94 participants from 29 institutions and 17 countries, with 53.9% using smeared crack models (SCMs), 30.8% a concrete damage plasticity (CDP) model, 3.8% discrete crack models (DCMs) and 11.5% considered as “other models.” From these simulations it was verified, in average terms, that SCM assured the best predictive performance apart from the average strain in the SFRC and the maximum crack width which were better predicted by DCM. More accurate predictions were obtained by using in‐house software than by adopting commercial software.
{"title":"Blind competition on the numerical simulation of slabs reinforced with conventional flexural reinforcement and fibers subjected to punching loading configuration","authors":"Joaquim A. O. Barros, Beatriz Sanz, Marcílio Filho, Petr Kabele, Rena C. Yu, Günther Meschke, Jaime Planas, Vitor Cunha, Gerrit E. Neu, Antonio Caggiano, Ventura Gouveia, Nilüfer Ozyurt, Elisa Poveda, Ab van den Bos, Jan Červenka, Erez Gal, Pierre Rossi, Daniel Dias‐da‐Costa, Peter K. Juhasz, David Cendón, Gonzalo Ruiz","doi":"10.1002/suco.202400061","DOIUrl":"https://doi.org/10.1002/suco.202400061","url":null,"abstract":"This paper describes the 3rd Blind Simulation Competition (BSC) organized by the <jats:italic>fib</jats:italic> WP 2.4.1 which aims to assess the predictive performance of models based on the finite element method (FEM) for analysis and design of fiber reinforced concrete (FRC) structures submitted to loading and support conditions that promote punching failure mode. Fiber reinforcement is used in an attempt to eliminate conventional punching reinforcement and provide technical and economic advantages. The two tested real‐size prototypes represent a column‐slab interior region of an elevated steel‐fiber reinforced concrete (E‐SFRC) slab where anti‐progressive collapse reinforcement is disposed in the alignment of columns/piles. Despite a punching failure surface being formed in both experimentally tested prototypes at the rupture stage, fiber reinforcement was able to mobilize the yield capacity of the conventional flexural reinforcement, providing high deformation capacity, and ductility to the prototypes. The average post‐peak load‐carrying capacity of the tested prototypes at a deflection seven times higher than the deflection at yield initiation of the conventional reinforcement was still 90% of the average peak load. Regarding the BSC, a total of 26 proposals were received and involved 94 participants from 29 institutions and 17 countries, with 53.9% using smeared crack models (SCMs), 30.8% a concrete damage plasticity (CDP) model, 3.8% discrete crack models (DCMs) and 11.5% considered as “other models.” From these simulations it was verified, in average terms, that SCM assured the best predictive performance apart from the average strain in the SFRC and the maximum crack width which were better predicted by DCM. More accurate predictions were obtained by using in‐house software than by adopting commercial software.","PeriodicalId":21988,"journal":{"name":"Structural Concrete","volume":"76 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141868671","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}
Rapid urbanization brings us challenges, but it is meant to bring us well‐being. The short lifetime of buildings and urban renewal policies have led to the demand for demolition. The aim of this study is to demonstrate the benefits of implementing an advanced demolition system and to fill the sustainability assessment gap in the demolition sector. This approach will help reduce obstacles to conducting sustainable demolition. To achieve this goal, an assessment system based on external costs was built, which mainly focused on the costs of damage due to global warming and environmental pollution. A case study employing two advanced demolition systems was used to show how the assessment works and the effects of demolition. According to the assessment results, the total external damage for the two advanced demolition systems is 37.6% and 19.6% of that of the conventional demolition method. Excellent waste management causes damage due to global warming in only 9.4% of conventional demolition projects, but noise impacts are still a crucial issue in the demolition field, as they contribute to 74.4% of the total damage. Based on the case study results, the benefits of sustainable demolition and the future of demolition are revealed. Further development should be sought for future demolition through new design theory or new technology.
{"title":"Sustainability assessment of demolition based on quantitative external costs","authors":"Wang Li, Tamon Ueda","doi":"10.1002/suco.202300852","DOIUrl":"https://doi.org/10.1002/suco.202300852","url":null,"abstract":"Rapid urbanization brings us challenges, but it is meant to bring us well‐being. The short lifetime of buildings and urban renewal policies have led to the demand for demolition. The aim of this study is to demonstrate the benefits of implementing an advanced demolition system and to fill the sustainability assessment gap in the demolition sector. This approach will help reduce obstacles to conducting sustainable demolition. To achieve this goal, an assessment system based on external costs was built, which mainly focused on the costs of damage due to global warming and environmental pollution. A case study employing two advanced demolition systems was used to show how the assessment works and the effects of demolition. According to the assessment results, the total external damage for the two advanced demolition systems is 37.6% and 19.6% of that of the conventional demolition method. Excellent waste management causes damage due to global warming in only 9.4% of conventional demolition projects, but noise impacts are still a crucial issue in the demolition field, as they contribute to 74.4% of the total damage. Based on the case study results, the benefits of sustainable demolition and the future of demolition are revealed. Further development should be sought for future demolition through new design theory or new technology.","PeriodicalId":21988,"journal":{"name":"Structural Concrete","volume":"352 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776984","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}
Fabio Di Carlo, Zila Rinaldi, Alberto Meda, Filippo Molaioni
The paper presents an experimental study for the evaluation of the flexural response and failure mode of a prestressed concrete (PC) beam subjected to simultaneous sustained loads and corrosion. The obtained results are judged and discussed also through a comparison with the experimental outcomes on a reference sound PC beam, and a companion specimen subjected to artificial corrosion first, and then tested in bending. The three specimens are characterized by a 200 × 300 mm rectangular cross section, a total length of 3700 mm, and a clear span of 2700 mm. The value of the sustained load, applied with a simultaneous accelerated corrosion process of the strands, was chosen, based on the result of the uncorroded reference beam, to achieve a scenario that can occur in a real structure in situ. The flexural response of the tested element was monitored over a period of 70 days, up to failure, and showed to be highly dependent on the localization of the corrosion phenomena affecting the strands, especially when coinciding with the maximum bending moment position. The obtained results are finally compared with the ones obtained on a PC beam with the same geometry and material properties, first subjected to corrosion and then tested in bending. The differences in corrosion morphology and location and in the failure mode of the strand confirm the importance of accounting for the combined effect of reinforcement corrosion and loading when assessing the structural performance of PC beams.
本文介绍了一项实验研究，用于评估预应力混凝土（PC）梁在同时承受持续荷载和腐蚀的情况下的弯曲响应和破坏模式。本文还通过与参照健全 PC 梁的实验结果以及先进行人工腐蚀然后再进行弯曲测试的同伴试样进行比较，对所获得的结果进行了判断和讨论。这三个试样的横截面为 200 × 300 毫米的矩形，总长度为 3700 毫米，净跨度为 2700 毫米。在对钢绞线进行加速腐蚀的同时施加的持续荷载值是根据未腐蚀参考梁的结果选定的，以实现在实际结构中可能发生的情况。在 70 天的时间里，对受测元件的弯曲响应进行了监测，直至其失效，结果表明，这种响应与影响钢绞线的腐蚀现象的局部性有很大关系，尤其是与最大弯矩位置相吻合时。最后，将所获得的结果与在具有相同几何形状和材料特性的 PC 梁上获得的结果进行了比较，后者首先受到腐蚀，然后进行了弯曲测试。腐蚀形态和位置以及钢绞线破坏模式的差异证明，在评估 PC 梁的结构性能时，考虑钢筋腐蚀和荷载的综合影响非常重要。
{"title":"Experimental behavior of prestressed concrete beams under simultaneous sustained loading and corrosion","authors":"Fabio Di Carlo, Zila Rinaldi, Alberto Meda, Filippo Molaioni","doi":"10.1002/suco.202400304","DOIUrl":"https://doi.org/10.1002/suco.202400304","url":null,"abstract":"The paper presents an experimental study for the evaluation of the flexural response and failure mode of a prestressed concrete (PC) beam subjected to simultaneous sustained loads and corrosion. The obtained results are judged and discussed also through a comparison with the experimental outcomes on a reference sound PC beam, and a companion specimen subjected to artificial corrosion first, and then tested in bending. The three specimens are characterized by a 200 × 300 mm rectangular cross section, a total length of 3700 mm, and a clear span of 2700 mm. The value of the sustained load, applied with a simultaneous accelerated corrosion process of the strands, was chosen, based on the result of the uncorroded reference beam, to achieve a scenario that can occur in a real structure in situ. The flexural response of the tested element was monitored over a period of 70 days, up to failure, and showed to be highly dependent on the localization of the corrosion phenomena affecting the strands, especially when coinciding with the maximum bending moment position. The obtained results are finally compared with the ones obtained on a PC beam with the same geometry and material properties, first subjected to corrosion and then tested in bending. The differences in corrosion morphology and location and in the failure mode of the strand confirm the importance of accounting for the combined effect of reinforcement corrosion and loading when assessing the structural performance of PC beams.","PeriodicalId":21988,"journal":{"name":"Structural Concrete","volume":"12 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776985","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}
Ali Abdelrahim Mohamed, Osama Ali, Ibrahim M. Metwally
The present article aims to study the behavior of RC columns under blast loading. A nonlinear dynamic Three‐Dimensional (3D) Finite Element FE model‐based explicit solver available in ABAQUS Software is used. A parametric study is investigated to enhance the blast resistance of RC columns under three different scaled distances z of an explosion, that is, 0.23, 0.5, and 1.07 m/kg1/3 for close, intermediate, and Far in‐distance. In addition, three levels of concrete grades are used, which are Normal Strength Concrete (NSC), High Strength Concrete (HSC), and Ultra High‐Performance Concrete (UHPC). The study also considers Three reinforcement ratios for longitudinal and transverse reinforcement ratios of (ρL = 1.28%, 2.4%, and 3.1%) and (ρs = 0.6%, 0.9%, and 1.35%), respectively. Further, three different Axial Load Ratios, ALR = 0.01, 0.2, and 0.4, are considered to examine the effect of increasing ALR on the RC column under close explosion. For more investigation, the parametric analysis considers two geometrical shapes of RC columns (square and circular). The material behaviors of concrete and reinforcing steel bars are represented using Concrete Damage Plasticity (CDP) and Johnson–Cook (J–C) models, respectively, available in ABAQUS Software. The FE model has been initially validated against experimental study. The FE‐predicted deflection and damage were observed and agreed with the practical cases. In addition, the parametric study's results demonstrate that the RC column's blast deflection is significantly reduced with increasing reinforcement ratios. However, increasing concrete grade could efficiently reduce blast damage and deflection. Furthermore, compared with NSC, UHPC significantly reduced maximum damage and deflection by around 60% for square and 55% for circular columns, respectively.
{"title":"Blast performance of RC columns with different levels of concrete grades and reinforcing ratios","authors":"Ali Abdelrahim Mohamed, Osama Ali, Ibrahim M. Metwally","doi":"10.1002/suco.202400083","DOIUrl":"https://doi.org/10.1002/suco.202400083","url":null,"abstract":"The present article aims to study the behavior of RC columns under blast loading. A nonlinear dynamic Three‐Dimensional (3D) Finite Element FE model‐based explicit solver available in ABAQUS Software is used. A parametric study is investigated to enhance the blast resistance of RC columns under three different scaled distances <jats:italic>z</jats:italic> of an explosion, that is, 0.23, 0.5, and 1.07 m/kg<jats:sup>1/3</jats:sup> for close, intermediate, and Far in‐distance. In addition, three levels of concrete grades are used, which are Normal Strength Concrete (NSC), High Strength Concrete (HSC), and Ultra High‐Performance Concrete (UHPC). The study also considers Three reinforcement ratios for longitudinal and transverse reinforcement ratios of (<jats:italic>ρ</jats:italic><jats:sub><jats:italic>L</jats:italic></jats:sub> = 1.28%, 2.4%, and 3.1%) and (<jats:italic>ρ</jats:italic><jats:sub><jats:italic>s</jats:italic></jats:sub> = 0.6%, 0.9%, and 1.35%), respectively. Further, three different Axial Load Ratios, ALR = 0.01, 0.2, and 0.4, are considered to examine the effect of increasing ALR on the RC column under close explosion. For more investigation, the parametric analysis considers two geometrical shapes of RC columns (square and circular). The material behaviors of concrete and reinforcing steel bars are represented using Concrete Damage Plasticity (CDP) and Johnson–Cook (J–C) models, respectively, available in ABAQUS Software. The FE model has been initially validated against experimental study. The FE‐predicted deflection and damage were observed and agreed with the practical cases. In addition, the parametric study's results demonstrate that the RC column's blast deflection is significantly reduced with increasing reinforcement ratios. However, increasing concrete grade could efficiently reduce blast damage and deflection. Furthermore, compared with NSC, UHPC significantly reduced maximum damage and deflection by around 60% for square and 55% for circular columns, respectively.","PeriodicalId":21988,"journal":{"name":"Structural Concrete","volume":"84 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141785623","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 use of UHPC enables reducing the height of composite slabs, which may decrease the punching shear capacity. This paper investigates the punching shear behavior of steel‐normal concrete‐UHPC composite slabs with experiments and theoretical analyses. Results indicated that a 50 mm UHPC layer makes the nominal punching shear strength increase by 24.91%. Utilizing UHPC and increasing loading area can effectively enhance the punching shear capacity. Besides, theoretical punching shear model proposed based on rigid‐plastic theory can reliably predict the punching shear capacity of composite slabs. The punching shear angle derived from strength theory closely matches the experimental values.
{"title":"Experimental and theoretical research of the punching shear performance of steel‐normal concrete‐UHPC composite slabs","authors":"Songsong Guo, Chao Liu","doi":"10.1002/suco.202400158","DOIUrl":"https://doi.org/10.1002/suco.202400158","url":null,"abstract":"The use of UHPC enables reducing the height of composite slabs, which may decrease the punching shear capacity. This paper investigates the punching shear behavior of steel‐normal concrete‐UHPC composite slabs with experiments and theoretical analyses. Results indicated that a 50 mm UHPC layer makes the nominal punching shear strength increase by 24.91%. Utilizing UHPC and increasing loading area can effectively enhance the punching shear capacity. Besides, theoretical punching shear model proposed based on rigid‐plastic theory can reliably predict the punching shear capacity of composite slabs. The punching shear angle derived from strength theory closely matches the experimental values.","PeriodicalId":21988,"journal":{"name":"Structural Concrete","volume":"43 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141785625","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}
Ibrahim Y. Hakeem, Bothaina Osama, Weiwen Li, Peng Wang, Yao Lu, Md. Habibur Rahman Sobuz, Mohammed Ghalib Al Hudeesh, Walid Mansour
The aim of this study is to explore the applicability of externally bonded fiber‐reinforced polymer (FRP) composites to enhance the structural performance of steel–concrete composite beams with web openings in terms of load capacity and stiffness. In order to achieve this aim, the ABAQUS software was used to create a three‐dimensional (3D) non‐linear finite element model (FEM) to simulate the behavior of FRP‐strengthened continuous composite beams with web openings exposed to monotonic loadings. After ascertaining the accuracy of the proposed model's results in successfully predicting failure patterns and load capacities of the experimentally tested specimens available in the literature, the suggested model was used to create a parametric study. The parametric study focused on the impacts of the opening location, opening shapes, and opening area on the failure pattern, load carrying capacity, and stiffness of continuous steel–concrete composite beams. Additionally, strengthening the web openings using different configurations and lengths of FRP strips with and without bolts was investigated. Results showed that the presence of web openings in location 2 exhibited the lowest load capacity of all investigated beams (20.80%–42.50% lower than the control composite beam). Moreover, the continuous composite beams with a circular opening were the best case and gave a higher failure load as compared to the rectangular opening at all locations. Additionally, all the simulated FRP‐strengthened composite beams in the third group demonstrated significant values of load capacities and stiffness among all the analyzed specimens.
{"title":"Restoration of load capacity and stiffness of continuous steel–concrete composite beams having web openings using externally applied FRP strips","authors":"Ibrahim Y. Hakeem, Bothaina Osama, Weiwen Li, Peng Wang, Yao Lu, Md. Habibur Rahman Sobuz, Mohammed Ghalib Al Hudeesh, Walid Mansour","doi":"10.1002/suco.202300895","DOIUrl":"https://doi.org/10.1002/suco.202300895","url":null,"abstract":"The aim of this study is to explore the applicability of externally bonded fiber‐reinforced polymer (FRP) composites to enhance the structural performance of steel–concrete composite beams with web openings in terms of load capacity and stiffness. In order to achieve this aim, the ABAQUS software was used to create a three‐dimensional (3D) non‐linear finite element model (FEM) to simulate the behavior of FRP‐strengthened continuous composite beams with web openings exposed to monotonic loadings. After ascertaining the accuracy of the proposed model's results in successfully predicting failure patterns and load capacities of the experimentally tested specimens available in the literature, the suggested model was used to create a parametric study. The parametric study focused on the impacts of the opening location, opening shapes, and opening area on the failure pattern, load carrying capacity, and stiffness of continuous steel–concrete composite beams. Additionally, strengthening the web openings using different configurations and lengths of FRP strips with and without bolts was investigated. Results showed that the presence of web openings in location 2 exhibited the lowest load capacity of all investigated beams (20.80%–42.50% lower than the control composite beam). Moreover, the continuous composite beams with a circular opening were the best case and gave a higher failure load as compared to the rectangular opening at all locations. Additionally, all the simulated FRP‐strengthened composite beams in the third group demonstrated significant values of load capacities and stiffness among all the analyzed specimens.","PeriodicalId":21988,"journal":{"name":"Structural Concrete","volume":"27 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776986","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}
Tao Wang, Jun Xu, Dagang Du, Chuanye Su, Xiaofei Shi
The interfacial cohesion between precast normal concrete (NC) and cast‐in‐place ultra‐high performance concrete (UHPC) is an important index to evaluate their interfacial bond strength, which is of great importance for the application of UHPC as a connection material for precast structural bridges. Interfacial cohesion is related to several influencing factors. However, there needs to be more research on the interrelationship model between multiple influencing factors and interfacial cohesion. This study took the UHPC wet joint in a precast concrete structure as the object. First, the relationship between the interface cohesion of UHPC wet joint and substrate strength, UHPC age, interfacial roughness, interfacial moisture content, and curing method was studied; The result shows that the key factors affecting interfacial cohesion include UHPC age, interface roughness, and substrate strength, with interfacial moisture content potentially playing a secondary role. Second, the failure types of the interface zone surface by using digital image correlation (DIC) are divided into three categories. Finally, the quantitative mathematical model of interfacial cohesion under the coupling effect of multiple factors was established based on the above four factors. The model is in good agreement with the experimental data.
{"title":"Interfacial cohesion model of ultra‐high performance concrete wet joints under the influence of multiple factors","authors":"Tao Wang, Jun Xu, Dagang Du, Chuanye Su, Xiaofei Shi","doi":"10.1002/suco.202300909","DOIUrl":"https://doi.org/10.1002/suco.202300909","url":null,"abstract":"The interfacial cohesion between precast normal concrete (NC) and cast‐in‐place ultra‐high performance concrete (UHPC) is an important index to evaluate their interfacial bond strength, which is of great importance for the application of UHPC as a connection material for precast structural bridges. Interfacial cohesion is related to several influencing factors. However, there needs to be more research on the interrelationship model between multiple influencing factors and interfacial cohesion. This study took the UHPC wet joint in a precast concrete structure as the object. First, the relationship between the interface cohesion of UHPC wet joint and substrate strength, UHPC age, interfacial roughness, interfacial moisture content, and curing method was studied; The result shows that the key factors affecting interfacial cohesion include UHPC age, interface roughness, and substrate strength, with interfacial moisture content potentially playing a secondary role. Second, the failure types of the interface zone surface by using digital image correlation (DIC) are divided into three categories. Finally, the quantitative mathematical model of interfacial cohesion under the coupling effect of multiple factors was established based on the above four factors. The model is in good agreement with the experimental data.","PeriodicalId":21988,"journal":{"name":"Structural Concrete","volume":"43 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141740613","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 partial factor method is widely employed as a design approach for structural reliability and serves as a crucial foundation for structural design codes. However, in practical applications, this method has gradually revealed shortcomings, such as issues with generality and insufficient precision in reliability control. In this article, an improved design value method for the bearing capacity design of steel plate strengthened RC beams was established. Additionally, considering the impact of the live‐to‐dead load effect ratio on the partial safety factor of resistance, a simplified expression for the ultimate limit state design of bearing capacity was proposed. The results show that the reliability index calculated using the partial factor method for the bearing capacity of steel plate strengthened RC beams has a significantly larger relative error. In contrast, the reliability indexes calculated based on the improved design value method are all greater than the target reliability index, ensuring the requirements of reliability design and providing a higher degree of precision in reliability control.
{"title":"Reliability design for bearing capacity of steel plate strengthened RC beams based on the improved design value method","authors":"Yuting Tong, Jitao Yao, Luyang Zhang","doi":"10.1002/suco.202400311","DOIUrl":"https://doi.org/10.1002/suco.202400311","url":null,"abstract":"The partial factor method is widely employed as a design approach for structural reliability and serves as a crucial foundation for structural design codes. However, in practical applications, this method has gradually revealed shortcomings, such as issues with generality and insufficient precision in reliability control. In this article, an improved design value method for the bearing capacity design of steel plate strengthened RC beams was established. Additionally, considering the impact of the live‐to‐dead load effect ratio on the partial safety factor of resistance, a simplified expression for the ultimate limit state design of bearing capacity was proposed. The results show that the reliability index calculated using the partial factor method for the bearing capacity of steel plate strengthened RC beams has a significantly larger relative error. In contrast, the reliability indexes calculated based on the improved design value method are all greater than the target reliability index, ensuring the requirements of reliability design and providing a higher degree of precision in reliability control.","PeriodicalId":21988,"journal":{"name":"Structural Concrete","volume":"21 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776987","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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