Behaviour factor (q) evaluation the CFS braced structures according to FEMA P695

Abstract

An upgrade of the construction standards is required to promote the use of lightweight steel structures in seismic areas of Europe. European earthquake standard EN1998-1 does not provide seismic design guidelines for the energy dissipative structural typologies in lightweight steel constructions. CFS strap-braced stud wall is an all-steel solution to dissipate the seismic energy in lightweight steel constructions. In this regard, a numerical study is performed to provide suitable value of the behaviour factor (q) for CFS strap-braced stud wall following the procedures of FEMA P695. A set of fourteen archetypes, which represented the range of design parameters and building configurations are designed following the capacity design approach. Numerical models with the ability to simulate the non-linear response of archetype buildings are then developed and analysed using non-linear static and dynamic analysis procedures. A suite of 44 normalized and scaled earthquake records, representing the probable seismic hazard to the buildings, is used for the incremental dynamic analysis. Performance of archetypes is evaluated by measuring their collapse fragility. Based on the results, it is concluded that the design method used in this study and a behaviour factor (q) of 2.5 for CFS strap-braced stud wall are appropriate to be include in next edition of the Eurocodes.