ABSTRACT
The good performance of steel moment-resisting frames under seismic motions depends strongly on the behaviour of their beam-to-column connections. The recent earthquakes generated an urgent need to increase the ductility of the connections normally used in practice. This paper presents a study of beam-to-column joints suitable for the case of column-tree configuration of moment-resisting frames, where tapered flanges are used to improve the seismic behaviour. Two types of joints are proposed and tested: type A, considered as an improved ‘conventional’ joint, and type B, that may be regarded as a ‘new-generation’ 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 Faculty of Civil Engineering, University of Architecture, Civil Engineering and Geodesy (UACEG), Sofia, within the framework of the European RECOS project. Both specimen types exhibited stable hysteretic behaviour with adequate ductility and energy dissipation capacity. Though both variants were quantitatively comparable, the most significant advantage of type B was found in its predictable behaviour.
