In different seasons, the matters needing attention in the construction of arch structure are different. How many points should we pay attention to in winter steel structure construction? 

　　1.The fabrication and installation of steel structure in winter construction shall be carried out in strict accordance with relevant regulations on winter construction of steel structure. 

　　2.When steel members are manufactured at positive temperature and installed at negative temperature, the shrinkage of steel members should be considered according to the difference of ambient temperature, and technical measures to adjust the deviation should be taken in construction. 

　　3.The welders who participate in the construction of negative temperature steel structure shall receive negative temperature welding process training, pass the examination and obtain the corresponding certificate. 

　　4.The steel and relevant connecting materials used at negative temperature shall be attached with quality certificate, and the performance shall meet the requirements of design and product standards. 

　　5.The welding rod used under negative temperature shall not be exposed for more than 2 hours, and shall be baked again after 2 hours. The welding rod shall be baked for no more than 3 times. 

　　6.The flux shall be baked according to the regulations before use to make its moisture content not exceed 0.1%. 

　　7.High strength bolts used under negative temperature must have product qualification certificate, and the torque coefficient and axial force shall be rechecked under negative temperature. 

　　8.Water coating shall not be used for steel structure under negative temperature. 

　　9.The shrinkage allowance should be reserved during the blanking of components, and the welding shrinkage and compression deformation should be coordinated with the shrinkage deformation of steel under negative temperature. 

　　10.During the assembly of components, the assembly shall be expanded from the inside to the outside according to the sequence specified in the process, and the weld shrinkage value to be reserved shall be determined by test during the assembly at negative temperature.