Experimental study on the behaviour of an i-beam to SHS-column by t-stub bolted connection

Abstract

In 80’s and 90’s hollow sections (HS) were mainly used in compression and tension elements of truss systems. Nowadays, architects are more and more using hollow sections in building applications where limited amount of research is available especially considering the economics of prefabrication to produce connections with acceptable ductility performance. In most of the examined joint types, the connection elements were welded on the tubular sections. This research is focused on the behaviour of I-beam to HScolumn t-stub bolted connections under monotonic and cyclic loading conditions. In view of easy and economic bolted field application and transportation without damage by leaving the column exterior without projections, in proposed joint type t-stubs are bolted by using long partially threaded studs through HS column. Four full scale beam-column specimens have been tested in two groups. As a difference the rear face of the HS column at the connection area has been reinforced by backing plate in the second group of specimens. Considering the cyclic performances, both joints maintain high plastic rotations in adequate resistance levels with acceptable energy dissipation capacities; consequently are suitable for use as semi-rigid partial strength joints in simply designed braced steel frames in seismic areas or in unbraced steel frames in less seismic areas. Additional research on the connection components has also been performed to observe the component behaviour of the column face in bending. Applicability of the component method described in Eurocode 3 part 1-8 with proposed design approach is checked by comparing with the test results both in resistance and stiffness point of view.