Improved beam-to-column joints for moment-resisting frames-an experimental study

摘要

The good performance of steel moment-resisting franes under seismic motions depends strongly on the behaviour of their beam-to-column connections.The Northridge earthquake generated an urgent need to increase the ductility of the connections normally used in practice.This paper presents the study of beam-to-column joints in column-0tree configuration of moment-resisting frames.Tapered flanges are used to improve the seismic behaviour of beams.Two types of joints are porposed and tested: type A.,considered as an improved pre-Northridge joint,and type B,as a post-Northridge detail.Experimental investigation on six (3+3) full-scale specimens was carried out.The tests were performed in the Steel Structures Research Laboratory of the University of Architecture,Civil Engineering and Geodesy (UACEG),Sofia.Both specimen types exhibited stable hysteretic behaviour with adequate ductility and energy dissipation capacity.Though both variatns are quantitatively comparable,the most significant advantage of type B is found in its predictable behaviour.