The site connection of this project is divided into multi-section welding and hoisting, and the site weld length is long. In addition, thick plate welding, high strength steel welding, steel casting welding, etc. Most of them are involved, which leads to considerable workload, high difficulty and more overhead welding. In this project, there are both thin plate welding and thick plate welding, both flat welding, vertical welding and overhead welding, both high-strength steel welding and steel casting welding, and the welding workload is large. The welding deformation of thin plate is large, and the welding deposition of thick plate is large, which requires high temperature control and labor intensity. However, the weather-proof and low-temperature measures for high-altitude welding and welding in winter and rainy season make welding more difficult. Overlooking the "Bird's Nest" in Nanchang, people will find that its roof is relatively flat and smooth, unlike the roofs of ordinary buildings, which are equipped with rod-shaped or tower-shaped lightning rods, and there are no lightning protection belts and the like. Why? Isn't there any lightning protection measures for the Bird's Nest?

In fact, the lightning protection design of "Bird's Nest" adopts the most traditional lightning protection technology. By making full use of the advantages of building structure, the metal roof of the Bird's Nest, the steel members in the steel structure and the steel bars in the reinforced concrete are effectively connected by welding, and the "steel bars and iron bones" of the whole "Bird's Nest" constitute an ideal "cage lightning protection network". In order to prevent the human body from being damaged by lightning, equipotential bonding has been done in the parts that people can touch in the venue, such as steel columns. Almost all the equipment in the "Bird's Nest" is reliably connected with the "cage lightning protection network" to ensure that the huge current generated by lightning can be introduced into the ground through the "cage lightning protection network" to ensure the safety of the venue itself, equipment and personnel to the greatest extent. The strength of steel used in Nanchang Bird's Nest is twice that of ordinary steel, and it is a special steel independently innovated and developed in China. The combination of rigidity and flexibility ensures that the Bird's Nest can still be restored to its original state after bearing the maximum external force of 460 MPa, that is to say, it can resist seismic waves similar to the Tangshan earthquake that year. The key to support the bird's nest is the structure of the "shoulder". The steel used in this part-"Q460" steel plate has a thickness of 1 10 mm, which has good seismic resistance, low temperature resistance and weldability. In order to meet the seismic requirements, the joints of steel members are particularly thickened, and all the members are connected by welding, which increases the stiffness and strength of the whole structure. The "Bird's Nest" has an extraordinary roof, and the 24 huge steel column feet supporting it are even more spectacular. In order to ensure that the "Bird's Nest" built in the high-intensity earthquake area with 8-degree seismic fortification can gain a firm foothold, the researchers and designers have overcome the situation that the column foot of the "Bird's Nest" is large in size and complex in structure, and the calculation assumptions and design methods in the current code in China are difficult to apply, and added bases and rivets to these steel column feet to rivet the column feet firmly in concrete. The thickness of the cap at the foot of the column is as high as 4 ~ 6 meters, and 24 huge steel columns are firmly connected with 24 huge reinforced concrete piers to jointly support a huge "bird's nest".