The Performance Study Of Pushover Of Steel Frame With Haunch

After Northridge of America and Kobe of Japan’s earthquake, In order to avoid the traditional brittle failure in weld of beam-column joints, people put forward two new kinds of strengthen and weaken connection of steel structure. Their essence is to force the plastic hinge emerge on the beam which away from the surface of the column. Haunch node in this paper is one of the nodes which is the strengthen connection. Domestic study on the seismic response comparison and internal stress state of haunch is made, but pay less attention on the behavior of the frame with haunch.In this paper, with the help of SAP2000program, modal analysis and the pushover analysis of ordinary steel frame and the steel frame with haunch are made. The cycle of two types is drawn by modal analysis and the base shear and top displacement of performance point of two kinds of steel frame under frequent earthquake and rare earthquake are drawn by pushover analysis. And another Pushover analysis is based on the first Pushover analysis’s result witch as monitoring displacement witch draws storey displacement, storey drift angle and plastic hinge’s number and plastic hinge’s sequence of each member of two kinds of steel frame under frequent earthquake and rare earthquake. Judge the impact of haunched measures on the seismic performance of steel frame through analysis and comparison. The analysis results show that:1. Haunched measures make the stiffness of the steel frame change in the unit mass, thus change the cycle;2. Haunched measures make storey displacement of the steel frame decrease under frequent and rare earthquake;3. Haunched measures make storey drift angle of the steel frame decrease under frequent earthquake, whereas increase under rare earthquake, but two effects are little;4. Haunched measures significantly improve the quantity and the order of plastic hinge of the steel frame under rare earthquake, but the bottom of the column at the first layer of the steel frame with haunch run up to C stage, so haunch design needs to be strengthened as the weak component.