腹板嵌入式外包U形钢-混凝土组合梁正弯矩区受弯性能研究  

Positive flexural behavior of web-embedded U-shaped steel-concrete composite beam

作　　者：杨远龙 刘阳 杨庆杰 胡盛文 YANG Yuanlong;LIU Yang;YANG Qingjie;HU Shengwen(Laboratory of New Technology for Construction of Cities in Mountain Area of the Ministry of Education,Chongqing University,Chongqing 400045,China;College of Civil Engineering,Chongqing University,Chongqing 400045,China)

机构地区：[1]重庆大学山地城镇建设与新技术教育部重点实验室,重庆400045 [2]重庆大学土木工程学院,重庆400045

出　　处：《建筑结构学报》2023年第1期166-181,共16页Journal of Building Structures

基　　金：国家自然科学基金面上项目(52178112,51878098);国家自然科学基金青年基金项目(51208241)。

摘　　要：传统钢-混凝土组合梁需要焊接不同形式的抗剪连接件,为避免繁琐的焊接工序及焊接对钢材产生的不良影响,提出了腹板嵌入式外包U形钢-混凝土组合梁。在冷弯成型的U形钢腹板上部开槽,并嵌入到混凝土翼板,与板底横向钢筋共同组成带有混凝土榫连接件的腹板嵌入式外包U形钢-混凝土组合梁(WUCSB)。设计了8个WUSCB的正弯矩区受弯性能试验,考虑U形钢板厚度、连接件间距、混凝土翼缘板宽等参数的影响,分析组合梁的破坏模式,并基于荷载-挠度曲线和荷载-滑移曲线等试验结果对其刚度、承载力和延性等受力性能指标进行评价;建立了有限元模型,进行U形钢板厚度、混凝土翼缘板宽和梁底纵筋直径等3个参数的影响规律分析。试验结果表明:该组合梁满足完全抗剪连接,组合作用良好,U形钢可以达到全截面塑性,具有良好的整体受弯性能;增加U形钢板厚度和梁底纵筋直径可以提高组合梁的承载力;连接件间距、栓钉及箍筋对组合梁的承载力影响较小。基于试验结果和连接件的传力机理,给出了WUSCB抗剪连接度的计算方法;基于全截面塑性假定,给出了WUSCB受弯承载力设计方法,该承载力设计方法具有一定的安全储备。基于换算截面法,给出了受弯刚度计算方法,出于安全考虑,抗弯刚度折减系数建议取值为0.55。Conventional steel-concrete composite beams require welding of different forms of shear connectors.To avoid the tedious welding process and the adverse effects of welding on steel members,a web embedded U-shaped steel-concrete composite beam was proposed in this paper.The upper part of the U-shaped steel web is slotted and embedded into the concrete slab to form a new type of web-embedded U-shaped steel-concrete composite beam(WUSCB)with concrete tenon connector,by involving the transverse reinforcement at the bottom of the plate.Eight WUSCB specimens were designed in a positive flexural behavior test.Considering the influence of U-shaped steel plate thickness,connector spacing,concrete flange width and other parameters,the failure modes were analyzed and summarized.The mechanical properties such as flexural capacity,stiffness and ductility were analyzed based on the load-deflection curves and the load-slip curves.A finite element model was established to further analyze the influence of three parameters,i.e.,the thickness of U-shaped steel,the width of concrete slab,and the diameter of longitudinal reinforcement at the beam bottom.The test results show that the WUSCBs can satisfy complete shear connection for composite action,and the U-shaped steel can reach the full section plasticity,which ensures that the concrete slab and steel web work together and has good overall flexural behavior.The flexural bearing capacity can increase with the increasing of thickness of the U-shaped steel and the increasing of the diameter of the longitudinal reinforcement at the beam bottom.The connector spacing,stud and hoop reinforcement have less effect on the bearing capacity of the composite beam.Based on the test results and the force transfer mechanism of the connector,the calculation method of the shear connection degree of WUSCB was proposed.The design method of the bending bearing capacity of WUSCB was proposed based on the assumption of plasticity of the full section,and this method has a amount of safety reserve.Based on

关 键 词：外包U形钢-混凝土组合梁 嵌入式抗剪连接件 受弯试验 受弯性能 

分 类 号：TU398.9[建筑科学—结构工程] TU317.1