Seismic Analysis On Box-Section Columns And I-Section Beams Rigid Connections In Steel Frames

Due to its good properties of mechanics, economy and use, steel structure is widely used in many fields, such as factories, bridges, large industrial equipments and buildings, especially in high-rise building. Steel moment-resisting frames consisting of welded flange-bolted web beam-to-column connections are widely used as lateral load resisting system in regions of high seismic risk, because of their merits of architecture usability (such as no lateral strut required) and facilely fabrication. In the recent earthquakes of USA and Japan, damages in many buildings resulted from the brittle frature of beam-to-column connections. The results is contrary to the original purposes. It requires people to do more research on how to design connections. So it is necessary to do more research on how to avoid damage in future.The thermal couple in the ANSYS Finite element programme stimulats the welds of upper flange and lower flange on the beam-to-column connections. Different welding orders and quality affect the distribution and proportion of the residual stress. It is necessary to check the weld during making. Welding residual stress in connections can not be ignored. If we want to advance the seimic capability of steel structures, we must take some new types of connections.The box-section frame columns have been widely used in civial steel buildings. Response and damage mechanism of welded-bolted I-beam to box-column connections under single and cyclical loads are analysed in the article. Integrating the advantage of improved rigid connections, the article provides welded haunch-cover joints and welded single hauch joints. Their seimic performance are also analysed. According the results, the article gives out design recommendations in seismic load. In order to precisely predict the fracture mechamism of welded-bolted beam-to-column joints under seismic load, an updated Lagrange finte element formulation involving is adopted in the FEM model. This FEM model involves steel ductility fracture criterions and brittle fracture index and reflects welded-bolted beam-to-column joints under cyclical load in reality. The approach adopted in this article is thought to be an original one.Many factors of the welded-bolted beam-to-column connections are caculated in the study . The FEM model can well simulate the fracture behavior of connections under earthquake. The conclusion and design recommendations are very useful for revising design specifications. This article can provide advices for more study about beam-to-column connections.