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通过3片开孔钢板(PBL)加劲型矩形钢管混凝土桁架和1片矩形钢管混凝土桁架受弯性能试验,研究主管内设PBL及节点支主管宽度比β对桁架破坏模式、支主管应变变化和极限承载力的影响,对桁架竖向挠度限值进行分析,并探讨节点变形对桁架整体变形的影响。结果表明:矩形钢管混凝土桁架和PBL加劲型矩形钢管混凝土桁架均发生节点破坏,主管内设PBL改变了管内混凝土的开裂模式,有效限制了混凝土裂缝发展,使钢管与混凝土更好地协同受力;矩形钢管混凝土桁架和β分别为0.5,0.75,0.875的PBL加劲型矩形钢管混凝土桁架的节点变形占桁架整体变形比例分别为33.43%,24.44%,23.69%和21.44%,PBL有效限制受拉支管处主管的外凸变形,使节点变形占桁架整体变形比例减小,提高节点承载力,但对受压支管处主管变形基本无影响;对于矩形钢管混凝土和PBL加劲型矩形钢管混凝土组合桁梁桥竖向挠度限值可参考《公路钢结构桥梁设计规范》(JTG D64—2015)取为桁架全长的1/500。
Through the bending test of three open-plank (PBL) stiffened rectangular concrete-filled steel tubular trusses and one rectangular CFST truss, the failure modes of the PBL and the width of the branch chiefly supported on the trusses, Bearing capacity of the truss vertical deflection limit analysis, and discuss the deformation of the truss deformation of the overall impact. The results show that the failure of the joints occurs between the rectangular CFST truss and the concrete filled rectangular steel tube with PBL stiffeners. The PBL inside the main pipe changes the cracking mode of concrete in the pipe, effectively restricting the development of concrete cracks and making the pipe and concrete work well together. The total deformation of truss with rectangular CFST truss and PBR stiffened rectangular CFST truss with β of 0.5, 0.75 and 0.875 respectively accounted for 33.43%, 24.44%, 23.69% and 21.44%, respectively. The convex deformation of the supervisor causes the deformation of the joint to reduce the overall deformation ratio of the truss and enhances the bearing capacity of the joint but has little effect on the deformation of the main pipe at the pressurized branch pipe. For the rectangular CFST and PBR stiffened rectangular CFST truss bridge To the deflection limit can refer to “Design Code for Highway Steel Structure Bridge” (JTG D64-2015) taken as the whole length of the truss 1/500.