某钢管桁架盆式支座拔出原因分析与处理

Cause Analysis and Treatment of Pull⁃out of Basin Support of a Steel Pipe Truss

德州市某高铁站门厅为大跨度钢管桁架结构,分主拱桁架及次拱桁架。主拱桁架设计支座采用不约束竖向位移的滑动支座,主拱桁架及次拱桁架采用相贯节点焊接连接。桁架施工季节为夏季,主、次拱桁架节点焊接完成后发现主、次拱桁架大部分盆式支座拔出。发现支座拔出问题后安装位移计与应变计对支座位移及杆件应力进行实时监测,并结合结构分析软件3D3S和有限元分析软件MIDAS GEN对不同荷载工况下的支座位移及杆件应力进行计算,分析支座拔出原因并给出处理方案。

The entrance hall of a high⁃speed railway station in Dezhou is a large⁃span steel pipe truss structure,which is divided into main arch truss and secondary arch truss.The design support of the main arch truss adopts the sliding support without constraining the vertical displacement,and the main arch truss and the secondary arch truss are welded by intersecting joints.The truss construction season is summer.After the welding of the main and secondary arch truss joints is completed,it is found that most of the basin supports of the main and secondary arch trusses are pulled out.After the problem of bearing pull⁃out was found,the displacement meter and strain gauge were installed to monitor the displacement of the bearing and the stress of the bar in real time.Combined with the structural analysis software 3D3S and the finite element analysis software MIDAS GEN,the displacement of the bearing and the stress of the bar under different load conditions were calculated,the cause of the bearing pull⁃out was analyzed and the treatment scheme was given.