In the building structure, the steel structure has the advantages of high seismic resistance, high industrialization, short construction period, energy conservation and environmental protection, convenient transportation, fast construction and good ductility. In particular, ductility of the steel structure building can attenuate the seismic wave.To reduce the destructive impact of the earthquake on the building based on the outstanding advantages of steel structures. For steel structures, it is necessary to understand the seismic damage of steel structures and their characteristics, the reinforcement of steel structures and the seismic design of steel structures, and it is necessary to reflect the seismic design goals of large earthquakes and small earthquakes.
Seismic damage characteristics of steel structures
The main damage of steel structure is the failure of node connection, the destruction of components and the overall collapse of structure.
First, the destruction of the node connection
1, the frame beam column node area of destruction reasons
1) Weld metal impact toughness is low;
2) There are defects in the weld, especially in the middle of the weld on the bottom of the lower flange, which is not continuous due to the obstruction of welding and inspection by the web;
3) the edge of the beam flange full groove weld bevel edge of the formation of artificial joints, under the action of vertical force to expand;
4) Beam edge weld stress concentration through the edge of the hole, causing cracks to the flat material expansion;
5) The cracks mainly appear in the lower flange because the flanges on the beam have floor strengthening and the upper flange weld without web hinders welding.
2, supporting the destruction of the connection
In many earthquakes there has been destruction of the connection to the gusset plate or the destruction of the connection supporting the column. The form of bolting failure of the support, including the weakening of the support section at the fracture, the shear failure at the end of the joint plate, and the shear bar between the support bar screw slip damage.