腹板嵌入式外包U形钢-混凝土组合梁抗剪性能研究

STUDY ON SHEAR BEHAVIOR OF WEB-EMBEDDED U-SHAPED STEEL-CONCRETE COMPOSITE BEAM

外包U形钢-混凝土组合梁具有承载力高、延性好等优势,其施工工艺也顺应了目前建筑结构装配式发展的趋势。该文采用与钢腹板一体的嵌入式抗剪连接件,设计了9个腹板嵌入式外包U形钢-混凝土组合梁(WUSCB)的剪切性能试验,考虑了剪跨比、混凝土翼板宽度、连接件间距及倾角、底部纵筋直径、栓钉和箍筋设置、U形钢腹板高厚比等参数的影响,分析并总结了各试件的破坏模式,基于剪力-跨中挠度曲线对比分析了各试件的承载力和延性等抗剪性能指标,基于剪跨区U形钢腹板等效应力的分布形式研究了剪力传递机理。采用ABAQUS有限元分析软件,针对WUSCB试件建立了有限元模型,进行了剪跨比、混凝土翼缘板宽度、腹板高厚比和底部纵筋配筋率四个参数的影响规律分析。基于试验结果和有限元参数分析结果,提出了WUSCB的抗剪设计方法,该方法考虑了混凝土、U形钢腹板和底部纵筋销栓作用对抗剪承载力的贡献,能较准确地预测WUSCB的抗剪承载力。

The U-shaped steel-concrete composite beam has the advantages of high bearing capacity and good ductility,and its assembling construction technology also conforms to the current trend of assembly-type building structures.In this paper,nine web-embedded U-shaped steel-concrete composite beams(WUSCB)were designed with embedded connectors.The influence of parameters such as shear span ratio,concrete slab width,connector spacing and inclination angle,diameter of bottom longitudinal rebar,configuration of bottom studs and stirrups,depth-to-thickness ratio of steel web were considered.The specimen failure modes were analyzed and summarized.The mechanical properties such as shear capacity and ductility were analyzed based on the shear-deflection curves.The shear transfer mechanism of U-shaped steel web was studied based on the equivalent stress distribution in shear span.By using finite element software ABAQUS,a finite element model of WUSCB specimen was established and verified.Employing the finite element model,the four parameters including shear span ratio,concrete slab width,web depth-to-thickness ratio and bottom rebar ratio were analyzed.Based on the test results and finite element parameter analysis results, a shear bearing capacity design method of WUSCB was proposed. The method takes into account the contribution of concrete, U-shaped steel webs and bottom longitudinal reinforcements, and can be used to accurately predict the shear bearing capacity of WUSCB.