带钢底板UHPC梁抗剪承载力计算方法  

Shear bearing capacity calculation method for UHPC beams with steel bottom plate

作　　者：晏班夫[1,2] 刘千 王凯 涂兵 柯璐 YAN Ban-fu;LIU Qian;WANG Kai;TU Bing;KE Lu(College of Civil Engineering,Hunan University,Changsha 410082,Hunan,China;School of Civil Engineering and Architecture,Guangxi University,Nanning 530004,Guangxi,China)

机构地区：[1]湖南大学土木工程学院,湖南长沙410082 [2]广西大学土木建筑工程学院,广西南宁530004

出　　处：《交通运输工程学报》2024年第3期82-93,共12页Journal of Traffic and Transportation Engineering

基　　金：国家自然科学基金项目(U23A20662,52208307);广西科技计划项目(AB23026154)。

摘　　要：为研究带钢底板的超高性能混凝土(UHPC)梁的抗剪性能和抗剪承载力计算方法,采用试验研究与理论分析的方法,设计制作了7片试验梁开展抗剪试验,试验参数包括接缝配置、纵向腹筋设置和剪跨比;结合极限平衡理论和分项线性叠加思想,建立了考虑箍筋、钢纤维、UHPC基体及钢板抗剪贡献的带钢底板UHPC梁抗剪承载力计算建议公式,并与法国规范计算公式进行比较。试验结果表明:接缝梁的破坏形态均为接缝处错位的剪切破坏,主裂缝沿靠近跨中的接缝一侧斜向发展,而完整梁的破坏形态与剪跨比有关,随着剪跨比的增加从剪压破坏向弯剪破坏转变;接缝的存在会降低带钢底板UHPC梁的抗剪承载力,且随剪跨比的增大而减小,设置纵向腹筋则可有效提高其抗剪承载力与变形能力;采用本文提出的计算方法的抗剪承载力计算值与试验值的平均比值为0.91,变异系数为0.16,采用法国规范抗剪承载力计算方法的抗剪承载力计算值与试验值的平均比值为1.08,变异系数为0.29,因此本文提出的计算方法离散性较小,可适用于带钢底板UHPC梁的抗剪承载力计算。To investigate the shear performance and the calculation method for the shear bearing capacity of ultra-high performance concrete(UHPC) beams with steel bottom plates,seven test UHPC beams were designed and fabricated for shear-resistance testing by test research and theoretical analysis,with test parameters including joint configuration,longitudinal web reinforcement layout,and shear span ratio.Combined with limit equilibrium theory and sub-item linear superposition,a recommended formula for calculating the shear bearing capacity of UHPC beams with steel bottom plates was established.Shear contributions from stirrups,steel fibers,UHPC matrix,and steel plates were considered in this formula.It was subsequently compared with the calculation formula prescribed by the French code.Test results show that the failure mode of joint beams is characterized by shear failure with joint malposition,with primary cracks progressing diagonally along the joint side near the mid-span.In contrast,the failure mode of intact beams is related to the shear span ratio,shifting from shear-compression failure to flexural-shear failure as the shear span ratio increases.The presence of joints reduces the shear bearing capacity of UHPC beams with steel bottom plates,and it decreases with the increase of the shear span ratio.The layout of longitudinal web reinforcement can improve the shear bearing capacity and deformability of these beams effectively.The average ratio of the calculated value of shear bearing capacity via the proposed method to the test value is 0.91,with a coefficient of variation of 0.16.In comparison,the average ratio of the calculated value of shear bearing capacity via the French code method to the test value is 1.08,with a coefficient of variation of 0.29.Therefore,the proposed calculation method exhibits lower discreteness and is applicable for the shear bearing capacity calculation of UHPC beams with steel bottom plates.5 tabs,10 figs,31 refs.

关 键 词：桥梁工程 UHPC梁 抗剪承载力 理论分析 钢底板 湿接缝 

分 类 号：U445.7[建筑科学—桥梁与隧道工程]