摘要
组合封闭箍筋由下部开口箍筋和上部箍筋帽组成,可显著提高混凝土叠合梁的施工效率。为研究组合封闭箍筋对叠合梁受扭性能的影响,本文开展了9根采用4种组合封闭箍筋混凝土叠合梁的单调纯扭试验,对不同构造的组合封闭箍筋混凝土叠合梁的破坏形态、极限承载力、延性及变形能力等进行了系统的研究。结果表明:9根梁的主裂缝均为约45°夹角的螺旋状,最终破坏均为纵筋及箍筋受拉屈服,混凝土压碎;采用组合封闭箍筋叠合梁的受扭承载力与采用封闭箍筋现浇梁基本相同,采用不同组合封闭箍筋的叠合梁的受扭承载力和扭转刚度相近;9根梁的扭转延性系数在9.0~13.2,其中采用形式4组合封闭箍筋(开口箍筋两侧135°弯折、箍筋帽两侧90°弯折)的叠合梁的延性系数高。基于中美规范对上述梁的开裂扭矩和受扭承载力进行计算,规范计算值与试验值吻合较好。
An overlapping hoop comprises a lower opening hoop and an upper cap;this design significantly improves the construction efficiency of composite concrete beams.To study the effect of overlapping hoops on the torsional performance of composite concrete beams,this study reports the testing of nine concrete beams using four types of overlapping hoops under pure torsion.The failure mode,ultimate bearing capacity,ductility,and deformation capacity of the concrete beams with different overlapping hoops are systematically studied.Test results show that major cracks occurring in the nine beams are all spiral with an inclined angle of approximately45°to the longitudinal axis,and all beams fail owing to concrete crush and yielding of longitudinal bars and hoops.The ultimate loading bearing capacity of the composite beams with overlapping hoops are primarily similar to that of composite beams with traditional hoops,and the ultimate loading bearing capacity and torsional rigidity of the composite beams with different types of overlapping hoops are similar.The ductility coefficients of the nine beams range from9.05to13.2,in which the ductility coefficient of beams using the fourth overlapping hoop(open hoop with both135°hooks,crosstie with both90°hooks)is greater than the others.Furthermore,cracking torque and ultimate torque are calculated according to Chinese concrete code and American concrete code;calculation results are similar to test results.
作者
张雷
代领杰
胡翔
薛伟辰
ZHANG Lei;DAI Lingjie;HU Xiang;XUE Weichen(Department of Building Engineering, Tongji University, Shanghai 200092, China)
出处
《哈尔滨工程大学学报》
EI
CAS
CSCD
北大核心
2017年第11期1745-1750,共6页
Journal of Harbin Engineering University
基金
上海市科委项目(15DZ1203502)
上海市建委项目(建管2014-001-001)
上海市国资委技术创新和能级提升项目(2015010)
关键词
组合封闭箍筋
叠合梁
纯扭
承载力
延性
裂缝
overlapping hoops
composite beams
pure torsion
bearing capacity
ductility
crack
