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采用非线性纤维梁模型建立了关键构件失效后钢管混凝土组合框架抗连续倒塌有限元模型。基于ABAQUS软件提供的二次开发平台UMAT,开发了考虑包辛格效应的钢材和约束效应的核心混凝土材料单轴本构模型,并利用已有文献中的试验结果对上述本构模型进行了验证。在此基础上,进行了不同参数(失效柱位置、跨度、层数、层高及失效时间)下抗连续倒塌特征响应分析,研究不同参数下该类结构的位移变化和倒塌规律。研究结果表明,失效柱位置、跨度以及失效时长对竖向位移时程曲线影响较大;中柱(底层、中间层和顶层)失效后,竖向位移时程曲线为比较规则的振荡衰减曲线,在阻尼作用下按照两条渐近线的趋势逐渐趋于平缓,而角柱失效后计算所得竖向位移时程曲线相对中柱不规则。为了更好地提高钢管混凝土结构的抗倒塌能力,给出了概念性的倒塌设防建议,供工程实际参考。
The non-linear fiber-beam model was used to establish the finite element model of continuous collapse of CFST frames after failure of key components. Based on UMAT, a secondary development platform provided by ABAQUS software, a uniaxial constitutive model of core concrete material considering the Bauschinger effect and restraining effect was developed and the above constitutive model was verified by using the existing experimental results . On this basis, the analysis of the characteristics of anti-continuous collapse response under different parameters (failure column position, span, layer number, story height and failure time) is carried out to study the displacement and collapse of such structures under different parameters. The results show that the position, span and failure time of failure column have a great influence on the vertical displacement time history curve. After failure of the middle column (bottom, middle and top), the vertical displacement time history curve is a regular oscillation decay curve, The trend of the two asymptotic lines gradually tends to be gentle under the damping effect. However, the vertical displacement time-series curve after the failure of the corner post is relatively irregular. In order to improve the anti-collapse ability of CFST structure better, a conceptual proposal of collapse and fortification is given for practical reference of engineering.