The assembly of steel structure is a very direct reason that directly affects the quality of steel structure. The wrong assembly directly affects whether the steel structure can be installed. If the assembly is not correct, the steel component can not be lifted at all. Therefore, the assembly control of steel structure is particularly important to the quality control of the whole steel structure.

      1、 Before the steel structure is assembled, the size and specification of the parts shall be carefully checked according to the requirements of the design drawings and the bill of materials provided by the processing workshop. The unqualified parts shall not be assembled and assembled.

      2、 Before assembly, the rust and oil stain within the range of 50 mm on the interface surface shall be polished with a grinding machine, and the flatness of the steel plate shall be carefully checked. If the flatness is not enough (such as the surface of the steel plate is wavy), it must be treated and leveled before assembly. 

      3、 When assembling H-beam, the perpendicularity of flange plate and web must be strictly guaranteed. The welding material for positioning welding must be consistent with the welding material. The spot welding height should not exceed 2 / 3 of the designed weld height. The weld length should not be less than 25 mm. The distance between welding points should be 450 mm-550 mm. The spot welding should be firm and reliable. The length of the weld should be increased at the lifting point.  

      4、 Assembly is to strictly meet the dimensional requirements. The positioning dimensions, installation dimensions and overall dimensions of components must be controlled within the scope of design requirements, and the dimensional tolerance shall not be greater than plus or minus 3mm.The distance between holes (center distance) is generally controlled in the range of plus or minus 1 mm.Those beyond the scope shall be rectified and qualified before assembly.For important parts of components (such as corbel, gusset plate, connecting plate, etc.), it is necessary to set up welding groove (plate above 8mm) at the welding position. The groove should be 45 ° and the groove size and direction should be consistent with the design drawings, and the surface should be polished before assembly.