低周往复荷载作用下自复位钢框架抗震性能研究

Seismic performance investigation of self-centering steel frame under cyclic loading

建立了1榀2跨3层以角钢为耗能元件的自复位钢框架结构有限元分析模型,详细介绍了模型的模拟与分析方法。钢绞线的预应力采用等效降温法施加,通过钢绞线提供的回复力可使结构在震后具有自复位能力。在加载过程中,为确保结构的自复位能力,预应力钢绞线要保持弹性。对结构模型施加由位移控制的往复荷载,并通过改变结构的初始预应力值及钢绞线的数量分析参数的改变对结构自复位性能及耗能能力的影响。分析结果表明:与传统钢框架相比,自复位钢框架的震后残余位移明显减小;在4%的层间位移角下,自复位钢框架梁柱及钢绞线均保持弹性状态,结构通过角钢的塑性耗散能量,震后框架具有自复位能力。

The finite element models of a planar self-centering steel frame structure with two bays and three storeys were built, in which angle steels were adopted as energy dissipation elements. The simulation and analysis method of the structures were introduced in detail. Equivalent cooling method is applied to provide pre-stress for the steel strands and the restoring force of the pre-stress steel strands makes the structure has self-centering capacity after earthquake. The steel strands remain elastic to maintain self-centering capability of the structures during the load process. Cyclic loading is applied to the structures by displacement control method. The influence on self-centering and energy dissipation capacity is analyzed by changing initial pre-stress and amount of the steel strands. The ana- lytical results show that the self-centering steel frame can greatly reduce the residual displacement comparing with traditional steel frame after the earthquake. Under 4% interstory drift ratio, the beams, columns and steel strands of the self-centering steel frame remain elastic while the angles sustain inelastic deformation for energy dissipation. After the earthquake, the self-centering steel frame has the self-centering capacity.