SEISMIC PERFORMANCE ASSESSMENT OF A SEVEN-STORY WOOD-STEEL HYBRID BUILDING

摘要

Performance based seismic design (PBSD) is a design paradigm which is beginning to be applied for steel and concrete structures. The ability of PBSD to incorporate various types of performance requirements and account for innovative construction techniques makes it a powerful tool, particularly in the design of new structural configurations. Modern mixed-use mid-rise wood frame buildings (4-8 stories) are ideal for combining a steel moment frame (SMF) at the first and/or second level to open the lower levels up for retail shops with wood used for the upper residential levels. The SMF provides enough strength for gravity load to support the upper levels, while providing substantial ductility and shear capacity. The interaction between the SMF and wood components for mid-rise woodframe buildings has not been adequately studied. The system behavior is not explicitly accounted for in existing building codes, other than the standard requirements for stiffness between successive story levels (e.g. IBC). In this paper, a seven-story structure, whose 1st-story is assumed to be a steel SMF supports six upper stories made of light-frame wood construction, is used as an example to illustrate a logical PBSD procedure which can be applied to these types of "hybrid" structures. The basic idea is that with the preliminary design of the wood portion of the building known, the effective stiffness of the steel frame can be determined based on the desired performance, which was assumed to be correlated with peak inter-story drift. Through this numerical study, the application of PBSD to wood-steel hybrid structures was illustrated and verified.