STR-863: DEVELOPMENT OF A NOVEL REPLACEABLE CONNECTION FOR SEISMICALLY DESIGNED STEEL CONCENTRICALLY BRACED FRAMES

There is increasing demand, from both engineers and their clients, for structures that can be rapidly returned to occupancy following an earthquake, while also maintaining or reducing initial costs. One possible way towards this goal is to ensure that seismic damage occurs only within elements that can be removed and replaced following a damaging earthquake. For concentrically braced frames that use hollow structural sections, the current design practice requires field welding of the brace to the gusset in a way that causes the brace to buckle out-of-plane. In the event of a damaging earthquake, the out-of-plane brace buckling may damage both the gusset plate and also any adjacent exterior cladding. The plate cannot be easily replaced, resulting in expensive and time-consuming repairs, and the damaged cladding could endanger the lives of people evacuating the building and of other pedestrians. This paper discusses the development of an alternative connection that can be bolted into place and that confines damage to replaceable components. The proposed connection is expected to result in reduced erection costs and be easier to repair following a major earthquake. Moreover, the new connection causes buckling to occur in plane, preventing dangerous damage to the cladding. Potential challenges in the design of such a connection are discussed and evaluated, and a finite element model that was created to confirm the performance of the proposed connection is also introduced. Finally, future areas of research and development of the connection are identified