弯剪扭荷载下配筋UHPC矩形梁的扭转性能与承载力计算  

Torsional Performance and Bearing Capacity Calculation of Reinforced UHPC Rectangular Beams Subjected to Combined Bending-shear-torsion

作　　者：柯璐 于硕 李传习 周佳乐[3,4] 裴必达 朱星畅 KE Lu;YU Shuo;LI Chuan-xi;ZHOU Jia-le;PEI Bi-da;ZHU Xing-chang(School of Civil Engineering and Architecture,Guangxi University,Nanning 530004,Guangxi,China;Key Laboratory of Bridge Engineering Safety Control of Ministry of Education,Changsha University of Science&Technology,Changsha 410114,Hunan,China;School of Civil Engineering,Changsha University of Science&Technology,Changsha 410114,Hunan,China;School of Environment and Civil Engineering,Dongguan University of Technology,Dongguan 523830,Guangdong,China)

机构地区：[1]广西大学土木建筑工程学院,广西南宁530004 [2]长沙理工大学桥梁工程安全控制教育部重点实验室,湖南长沙410114 [3]长沙理工大学土木工程学院,湖南长沙410114 [4]东莞理工学院生态环境与建筑工程学院,广东东莞523830

出　　处：《中国公路学报》2023年第9期157-171,共15页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(52078059,52208307);湖南省自然科学基金项目(2021JJ40593);长沙理工大学桥梁工程领域开放基金项目(19KB08)。

摘　　要：配筋超高性能混凝土(Ultra-high Performance Concrete,UHPC)梁在弯剪扭组合荷载作用(复合受扭)下的抗扭性能研究较为匮乏。为此,开展了8根配筋UHPC矩形梁的复合受扭试验,获得了各试件损伤破坏模式、扭矩-扭率曲线、扭矩-应变曲线及扭矩-裂缝宽度曲线,分析了配筋UHPC矩形梁复合受扭破坏机理,探讨了扭剪比、纵向配筋率对抗扭承载性能和延性的影响。试验结果表明:试件破坏形态为纯扭破坏和非纯扭(扭转、剪扭、弯扭)破坏;相比于纯扭试件,非纯扭试件表面未形成空间螺旋形裂缝,同时其正立面裂缝比背立面数量更多且更宽,非纯扭试件开裂扭矩降低46%~73%,抗扭承载力降低1%~38%,扭转延性系数提高38%~169%。随扭剪比从1增加到3,非纯扭试件抗扭承载力提高1%~21%,扭转延性系数提高24%~88%;随着纵向配筋率从0.78%增加到4.90%,试件抗扭承载力提高12%~27%,非纯扭试件扭转延性系数提高35%~88%,但纯扭试件扭转延性系数下降了31%。配筋UHPC复合受扭梁弯扭相关性符合“三折线”模型,基于弯扭“三折线”模型提出的复合受扭梁抗扭承载力公式计算值与试验值吻合良好,且对弯扭试件(含纯扭、扭转和弯扭破坏梁)具有更好的适用性。配筋UHPC复合受扭梁剪扭相关性符合“三折线”模型,将UHPC材料性能参数代入剪扭“三折线”模型中,基于修正的剪扭“三折线”模型提出的复合受扭梁抗扭承载力公式计算值与试验值吻合良好,且对剪扭试件(含纯扭、扭转和剪扭破坏梁)具有更好的适用性。Investigations of the torsional performance of reinforced ultra-high-performance concrete(UHPC)beams under bending-shear-torsion combined load(composite torsion load)are rare.In this study,composite torsional tests were conducted on eight reinforced UHPC rectangular beams,and their failure modes,torque-twist curves,torque-strain curves,and torque-crack width curves were obtained.The failure mechanisms of the reinforced UHPC rectangular beams subjected to composite torsion were analyzed,and the effects of the torsion-shear ratio and longitudinal reinforcement ratio on the ultimate torsional capacity and ductility were examined.According to the test results,the failure modes of specimens included pure torsion and non-pure torsion failure(including torsion,shear-torsion,and bending-torsion failures).Compared with the pure-torsion specimens,no spiral cracks formed on the surfaces of the non-pure torsion specimens at failure,and the front elevation had more and wider cracks than the back elevation.Compared with the pure-torsion specimens,the cracking torque of non-pure torsion specimens significantly decreased by 46%-73%,the ultimate torque decreased by 1%-38%,and the torsional ductility coefficient increased by 38%-169%.As the torsion-shear ratio increased from 1 to 3,the ultimate torque was increased by 1%-21%,and the torsional ductility coefficient was increased by 24%-88%.When the longitudinal reinforcement ratio was increased from 0.78%-4.9%,the ultimate torque was increased by 12%-27%,and the torsional ductility coefficient of the non-pure torsion specimens was increased by 35%-88%;however,the torsional ductility coefficient of the pure torsion specimens was decreased by 31%.The bending-torsion correlations of reinforced UHPC beams under composite torsion met the tri-linear model.Based on the bending-torsion tri-linear model,the calculation results of the ultimate torsion capacity formulas for the reinforced UHPC beams under composite torsion are in good agreement with the experimental results and could be used

关 键 词：桥梁工程 复合受扭 试验研究 超高性能混凝土 弯剪扭相关性 抗扭承载力 

分 类 号：U441.4[建筑科学—桥梁与隧道工程]