Seismic performance of steel frame with replaceable low yield point steel connection components and the effect of structural fuses

Abstract

In the context of high quality development of construction industry and the construction of resilient city, an innovative ductile and dissipative steel frame system with replaceable low yield point steel (LYP) components was proposed. By means of superposition of prefabrication function, damage control function and post-earthquake replaceable function, this quality solution was provided for satisfying the two-stage resilient design target of “the damage is controllable to achieve structural safety subjected to the earthquake excitation, and the structural function is restorable after earthquake with lower cost”. This multi-functional system relied on common connection methods (bolted connections with cover plates, T-stubs, or angle steels) and was easy to process and construct without additional complicated dissipative elements. Six numerical models of steel frames with different connection configurations were generated, namely five bolted three-storey steel frame structures with LYP connection components and a welded three-storey steel frame structure with reduced beam section. The static elastic-plastic analysis and nonlinear dynamic history analysis were carried out to explore the seismic performance of the overall structures and to verify the effect of structural fuses. The analysis results demonstrated that the steel frames with replaceable LYP connection components had good load-carrying capacity, desirable deformation capacity and dissipation capacity, meanwhile, the well-designed replaceable LYP connection components were able to concentrate plasticity and damage, to give full play to the role of structural fuses. The strategies of widening beam flanges at the root of beam and reducing the design resistance capacity coefficient were effective to improve the structural fuse effect. The desirable fuse effect can be realized with smaller required weakening degree in the case of widening beam flange.