Some problems and solutions in the construction process of steel structure engineering (2)

Connection problems
1. high strength bolt connection
1) The bolt equipment surface does not meet the requirements, resulting in poor installation of bolts, or the fastening degree of bolts does not meet the design requirements.
Cause analysis:
a). Here are floating rust, oil and other impurities on the surface, and there are burrs and welding tumors on the bolt hole.
b). The bolt surface is still defective after treatment.
Solutions:
a). Floating rust, oil and bolt hole defects on the surface of high-strength bolts should be cleaned one by one. Before use, it must be treated with anti-rust. Bolts should be kept and issued by special person.
b). The processing of the assembly surface should take into account the sequence of construction and installation, prevent repetition, and try to deal with it before hoisting.

2) Bolt screw damage, screw can not screw into the nut, affecting bolt assembly.
Cause analysis: the screw is seriously rusted.
Solutions:
① Bolts should be selected before use, and pre-matched after cleaning rust.
② Bolts damaged by the screw can not be used as temporary bolts, and it is strictly prohibited to force into the screw hole.
③ The bolt assembly should be stored according to the set and should not be exchanged when used.

2. Welding line problem: difficult to guarantee the quality; The main beams and columns of the floor are not welded; Arc plate is not used for welding.
Solutions: Before weld Steel Structure, check the quality approval of welding rod, the welding of the inspection certificate of approval, according to the design requirements for choosing welding rod, according to the instructions and procedures require to use welding rod, the weld surface must not have crack, weld beading. First and secondary weld shall have porosity, slag, crater crack. The weld shall not have defects such as edge biting and incomplete welding. First and secondary weld nondestructive testing in accordance with requirements, Check welder’s stamp at specified welds and positions. Unqualified welds shall not be processed without authorization, modify the process before processing. The number of weld repairs in the same part shall not be more than two times.