Behaviour of gusset plate connections to ends of round and elliptical hollow structural section members

Gusset plate connections to the ends of hollow structural section (HSS) members are regularly used in steel-framed buildings and roof trusses. Recent research on this connection type has indicated that current design recommendations for preventing tensile failure induced by shear lag may be overly conservative. This paper presents an experimental study on 13 gusset plate end connections to circular and elliptical HSS members under quasi-static tension and compression loadings. Current design proposals found in research studies and in design guides and specifications are compared with the experimental work. Various fabrication details for this connection type have been considered, and the influence of connection length, gusset plate orientation (in the tube long side versus short side), and distance between welds has been studied. In the experimental study, failure of all specimens under tensile loading was caused by circumferential fracture of the HSS or by tear-out of the HSS base material along the weld. The compression specimens failed by local buckling of the HSS at the connection end. A preferred static design approach for such connections is thus recommended.Key words: gusset plate, hollow section, tube, connection, round, elliptical, shear lag, tear-out failure.