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
作者
柯璐
于硕
李传习
周佳乐
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)
出处
《中国公路学报》
EI
CAS
CSCD
北大核心
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)。
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
bridge engineering
composite torsional behavior
experimental investigation
ultra-high performance concrete
bending-shear-torsion correlation
torsional capacity
