As a construction unit, after obtaining the construction drawings of the steel structure, it is necessary to organize experienced technical personnel to conduct a joint review of the drawings to see if there are any problems with the application specifications; Whether it is shown in the description, whether the specifications, models, performance, grades of various materials, construction quality requirements and safety level of the project are clear; whether the joint design is reasonable; whether there are insurmountable difficulties in the construction, etc. Unit is pre-moised. The perfection of design drawings is the prerequisite to ensure the quality of construction.

1. When cutting and blanking, the size of the flange plate is different, which causes the size of the H-shaped steel and the corbel to be inconsistent. The upper and lower flange plates of the steel beam connected with the corbel are misaligned by about one plate thickness; the cutting edge has a deep Cut marks, obvious depressions on the edge of the board, or deep sawtooth marks, excessive cutting roughness, non-vertical cutting of the edge of the panel, and excessive splicing;
2. During assembly, the H-steel is welded without a tire frame, resulting in a deviation in the height and dimension of the H-steel, and the web is off-center; after the wing web is butted, the weld is not leveled, and there are obvious bumps; the light steel web is not flat, Not rectified before assembly;
3. In terms of welding, light steel welded H-shaped steel wing plates are cut and then spliced. The welds are not equipped with arc extinguishing plates, resulting in incomplete welds, pits on the edges that are not fused, etc., and are not flush with the base metal; columns The size of the legs and corbels is smaller than the design drawings, and the fillet welds have serious edge sagging, and the arc closing point is generally lower than the base metal, and there are many pores; the welds welded by CO2 welding are poorly formed, with inconsistent widths and heights. Suddenly big and sometimes small; manual welding seams are not straight, wide and narrow, undercutting is serious; welding slag splashes are not cleaned;
4. In terms of drilling, the drawings were not well reviewed beforehand. In the place where a single row of holes should be opened, double rows of holes were opened. As a result, the holes were left on the component without filling. For example, the H-shaped steel at the connection between the column and the corbel has double rows of holes, while the H-shaped steel of the same specification as the girder and the secondary beam has a single row of holes, but both holes are opened with double rows of holes, which affects the strength and appearance quality after installation;
5. During the assembly process, the connection between the steel column corbel and the H-shaped steel beam was dislocated up and down, left and right, and the size was not well controlled; 6. Rust removal and painting: Rust removal was sloppy, did not meet the grade requirements, and the paint returned soon Rust and peeling; the thickness of the paint film is uneven, the thickness of the positive surface is generally super thick, up to 250μm, but the shade is often around 90μm (the thickness of the indoor paint film is specified as 125μm); the impurities are not cleaned before painting, there are many dirt, high and low Uneven, sag phenomenon is more common;
6. In the process of component transportation and stacking, there is no flat stacking of shelving parts, but random unloading, messy stacking, and even burying components in mud ditch, causing deformation, bruising and pollution of components;
7. When the components leave the factory, the centerline marks of steel columns and steel beams are not marked, which is quite common and brings difficulties to the installation and construction correction detection;
8. The splicing length of the wing web does not meet the requirements. For example, the splicing length of the flange plate should not be less than twice the width of the flange plate, the welding seam between the flange plate and the web plate should be staggered by more than 200mm, and the splicing length of the web plate should not be less than 600mm. However, the above requirements are often not met in practice.