摘要
外包内翻U形钢-混凝土组合梁(简称外包钢组合梁)与普通H形钢组合梁相比,具有承载力高、延性好、节省钢材、耐火和防腐性能好等优点,但目前关于外包钢组合梁负弯矩区受弯性能的研究较少。为了研究外包钢组合梁负弯矩区受弯性能,对4根简支组合梁进行了受弯试验研究,研究参数包括钢梁形式、抗剪连接件形式和纵筋排布方式。对比分析了各试件的破坏模式,基于荷载-挠度曲线和荷载-滑移曲线等试验结果,对其刚度、承载力和延性等力学性能进行了评价。试验结果表明,该组合梁满足完全抗剪连接,混凝土翼板与腹板能够协同工作,具有良好的整体抗弯性能。外包钢组合梁的延性优于H形钢组合梁;槽钢对滑移的抵抗效果和截面裂缝发展的控制效果优于栓钉;采用纵筋集中排布的组合梁,剪力滞后效应相较纵筋均匀排布组合梁更加明显。基于试验结果建立并验证了有限元模型,在此基础上进行了U形钢板厚度、翼板宽厚比和腹板高宽比等参数分析。结果表明:随着U形外包钢厚度的增加,试件纯弯段截面的屈服面积逐渐减小;翼板厚度对试件抗弯性能影响不大;随着腹板高宽比增大,腹板受压区高度升高,混凝土利用率上升;随着翼板宽度的增加,刚度及承载力也随之增加,剪力滞后效应明显。基于平截面假定和完全抗剪连接,提出负弯矩区抗弯承载力计算公式。该公式计算结果与试验及有限元计算结果吻合较好,且具有一定的安全储备,可用于工程设计。
The externally inverted U-shaped steel-concrete composite beam(referred to as the USCC beam)has high bearing capacity,good ductility,steel saving,fire resistance and good corrosion resistance compared with the ordinary H-shaped steel composite beam(HSCC beam).However,few study was conducted on the flexural performance of the negative moment zone of the USCC beam.In order to study the flexural performance of the negative moment zone of the USCC beam,the flexural test of 4 simply supported composite beams was carried out.The parameters studies included the type of steel beam forms,shear connectors and the arrangement of longitudinal reinforcement.Based on the test phenomena,load and deflection curves,load and slip curves were used to evaluate the mechanical performance of the beam.The analysis shows that the composite beam has complete shear connection performance,and the concrete slab and web are in good overall mechanical performance.Compared with HSCC beams,the USCC beam shows better ductility.In addition,the effect of channel steel connectors in resisting slip and controlling the development of section cracks is better than that of stud connectors.For the arrangement of longitudinal reinforcement,the shear-lag effect of the centralized arranged specimen is more obvious than that of the uniformly arranged specimen.To further study the performance of USCC beam,a finite element analysis(FEA)model was established based on the test results,whose effectiveness was verified.Based on the FEA model,parameters such as the thickness of U-shaped steel,the aspect ratio of concrete slab width to thickness and the aspect ratio of web height to width were analyzed.The results show that with the increase of U-shaped steel thickness,the yield height of the pure bending section decreases gradually,and the utilization rate of steel also decreases.The thickness of concrete slab has less impact on the bending performance.With the increase of web aspect ratio,the height of compression zone of web increases,and concrete utilization rate increases.When the width of concrete slab increases,stiffness and load-bearing capacity increase accordingly but shear-lag effect is obvious.Based on the plane section assumption and complete shear connection,a calculation formula for flexural capacity in negative moment zone was proposed.The calculated results are in good agreement with experimental and FEA results with a certain safety margin,which can be used for engineering design.
作者
江世永
吴泓滔
江泽申
赵毅
周剑
刘向刚
JIANG Shiyong;WU Hongtao;JIANG Zeshen;ZHAO Yi;ZHOU Jian;LIU Xianggang(School of Civil Engineering,Chongqing Jiaotong University,Chongqing 400074,China;China Academy of Building Research Co.,Ltd.,Beijing 100013,China;Shibei Power Supply Branch,State Grid Chongqing Electric Power Company,Chongqing 401120,China;Yujian Construction Industry Technology Group Co.,Ltd.,Chongqing 400060,China)
出处
《结构工程师》
2025年第1期118-132,共15页
Structural Engineers
基金
重庆市技术创新与应用发展专项重点项目(cstc2021jscx-gksbX0055)
重庆市建设科技计划项目(城科字2024第6-4)
重庆市建设科技计划项目(城科字2024第3-18)。
关键词
外包钢组合梁
负弯矩区试验
受弯性能
破坏模式
抗弯承载力
externally inverted U-shaped steel-concrete composite beams
negative moment zone
bending performance
destruction mode
bearing capacity
