Abstract：
Cangzhou Swimming Center adopts steel structure roof and the welding heat of truss bearing forces has obvious influence on quality and safety of steel structure. Therefore, main monitoring is made on the heat influence scope of suspended rod under primary truss during welding process between secondary truss circular tube and primary truss and the heat influence on forces borne by primary truss. It is proved that welding is dangerous after forces are applied on truss, so welding of components bearing forces shall give full consideration to the bearing capacity of structure, there should not be too many welding points and relevant protective measures shall be adopted.
