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对4个足尺W型柱试件进行受压屈曲试验,研究强震下多层支撑钢框架中柱的屈曲性能。工况包括单调、循环的轴心和偏心加载。在其中一个试验中施加动力循环荷载,在另一个循环试验中施加端弯矩。柱截面尺寸为W310×129(类型1),材质为ASTMA992钢。研究柱的长细比为48时绕弱轴屈曲的性能。基于杆件横截面的纤维离散化,采用数值方法模拟试件的响应。在数值模型中,描述并考虑了柱残余应力和应变率对材料属性的影响。研究表明:在地震作用下,钢柱能持续几个非线性屈曲循环,并承受重力荷载。仅在首次屈曲时,残余应力对柱的性能有影响,并在屈曲和降低受压承载力之前逐渐降低柱的切向刚度。强震下的高应变率提高了柱的屈曲强度和后屈曲强度。当采用非线性梁柱单元时,能充分预测钢柱的循环屈曲性能。在本模型中,通过横截面纤维离散化考虑了残余应力和应变率的影响。
Buckling tests on four full-scale W-shaped columns were carried out to study the buckling behavior of the columns in multi-layered steel frames under strong earthquake. Operating conditions include monotonous, cyclic axes and eccentric loading. In one of the tests, the dynamic cyclic loading was applied and in the other cyclic test the bending moment was applied. Column cross-section dimensions W310 × 129 (Type 1), made of ASTM A992 steel. Study of column slenderness ratio of 48 around the weak axis buckling performance. Based on the fiber discretization of rod cross-section, the response of the test piece is numerically simulated. In the numerical model, the effect of column residual stress and strain rate on material properties is described and considered. The research shows that under earthquake action, the steel columns can sustain several nonlinear buckling cycles and bear the gravity load. Residual stresses affect the column performance only for the first buckling and gradually reduce the column tangential stiffness before buckling and lowering the compressive load-bearing capacity. The high strain rate under strong earthquake increases the buckling strength and post-buckling strength of the column. When nonlinear beam-column elements are used, the cyclic buckling behavior of the steel columns can be fully predicted. In this model, the effects of residual stress and strain rate are taken into account by the discretization of the cross-section fibers.