Cast steel connectors for circular hollow section braces under inelastic cyclic loading

Although concentrically braced frames are an efficient means of providing lateral support in steel structures, many such frames designed to resist seismic loading and featuring hollow structural section braces have performed poorly in recent earthquakes-primarily due to unexpected connection failures. To address this issue, the use of a cast steel connector that fits between a tubular brace and a gusset plate is presented as an alternative to the reinforced, fabricated connections that are commonly used in seismic load resisting braced frames. The resulting connector was shaped using solid modeling software, verified by finite-element analysis, and finally cast to ASTM A958 standards. Laboratory results from static and cyclic testing of concentrically loaded brace-connector assemblies showed that the use of a cast steel connector is a viable means of connecting to tubular brace members for seismic (or even static) applications. Further, as the connector was crafted to fit a range of tubular members and can be mass produced, the proposed solution is an economical alternative to conventional tube-to-gusset connections under seismic loading.