Experimental study of steel-timber composite beam-to-column joints with extended end plates

Abstract

This study presents the results of laboratory push-down tests conducted on one pure steel and four steel-timber composite (STC) cruciform subassemblies to assess the failure characteristics, stiffness, flexural resistance and ductility of the extended end plate STC beam-to-column connections subjected to negative (hogging) bending moment. In the proposed composite system, the cross -laminated timber (CLT) panels were connected to the top flange of steel girders using coach screws and the steel beams were connected to the steel columns by bolted extended end plates. Moreover, the two juxtaposed CLT slabs (subject to tension) were connected by the mechanically anchored threaded rod and/or surface spline joints with steel plates. The experimental results showed that the extended end plate STC connection have enough rotation capacity to provide for plastic analysis/design of the STC beams. Furthermore, it was shown that the composite action in conjunction with continuity of timber slab can increase the bending moment capacity of the connection more than 50% of that for a pure steel connection.