Discussion on some problems in ultimate bending strength verification of rigid beam-column connections in earthquake-resistant steel frames

摘要

The ultimate bending strength of rigid beam-column connections is a key point ensuring structural safety of earthquake-resistant frames under major earthquakes.This paper discusses the ultimate bending strength design of Hsection beam-column connections.Based on a comparison of Chinese seismic code (GB50011)with European and Japanese codes,it is pointed out that for steel frames with plastic hinges expected to occur near beam ends under strong earthquakes,the beam-column connection coefficients stipulated by GB50011 code are at least not lower than those of the European code,and not smaller than those of the Japanese codes for general situations and even greater especially for the cases with large beam sections or high strength steels (higher than Q345).It is noted that the connection coefficient should vary with steel grades and using a constant value is not reasonable.Moreover,for beam splicing with short beams welded to columns,the potential plastic hinge region where splicing joints should be prevented is discussed and an equation for determining the splicing location is put forward.Finally,it is proposed that for the ultimate bending strength verification,the contribution of the beam web should be taken into account and recommended connection coefficients are given accordingly.