部分约束下组合梁柱子结构抗连续倒塌机理

为研究部分约束钢框架组合梁柱子结构的抗连续倒塌机理,对其进行数值模拟研究。利用ABAQUS软件建立了1:3缩尺的部分边界约束组合梁柱子结构的精细化数值模型,模型计算结果与试验结果吻合较好,验证了有限元建模方法的正确性。在此基础上建立足尺模型,分析边界约束侧向刚度、边柱尺寸、边柱轴压比对部分边界约束下组合梁柱子结构的抗连续倒塌性能的影响。结果表明:当弹簧约束系数n<1时,边界约束侧向刚度对组合梁柱子结构的抗连续倒塌性能影响显著,增大侧向约束刚度可有效提高组合梁柱子结构的抗连续倒塌性能; 当弹簧约束系数n>1时,增大侧向约束刚度对组合子结构的抗连续倒塌性能影响较小; 边柱尺寸过大或过小均不利于组合梁柱子结构抗连续倒塌性能的发挥,当梁柱线刚度比处于0.6～1.1区间时,边柱尺寸越大,悬链线机制发挥越充分,组合梁柱子结构的抗连续倒塌性能越好; 边柱轴压比对不同机制抗力的占比影响不大,但会影响组合梁柱子结构的承载能力,当边柱轴压比取0.3时,组合梁柱子结构的抗连续倒塌性能发挥最佳。

Anti-progressive Collapse Mechanism of Composite Beam-column Substructure with Partial Boundary Constraints

In order to investigate the anti-progressive collapse mechanism of composite beam-column substructure with partial boundary constraints, numerical simulation was carried out. The refined numerical model of a 1:3 scaled partial boundary constrained composite beam-column substructure specimen was established based on the ABAQUS software. The model calculation results were in good agreement with the test results, which verified the correctness of the finite element modeling method. On the basis, a full-scale model was established to analyze the influence of the lateral stiffness of the boundary constraint, the size of the side column, and the axial compression ratio of the side column on the anti-progressive collapse performance of the composite beam-column substructure with partial peripheral constraints. The results show that the lateral stiffness of the boundary restraint has a significant influence on the anti-progressive collapse performance of the composite beam-column substructure when the spring restraint coefficient n<1 and the anti-progressive collapse performance of the substructure is effectively improved when increasing the lateral restraint stiffness of the beam-column substructure. The increase in the lateral restraint stiffness has little influence on the anti-progressive collapse performance of the composite beam-column substructure when the spring restraint coefficient n>1. Too large or too small side column size is not conducive to the performance of the anti-progressive collapse performance of the composite beam-column substructure. The larger the side column size, the better the anti-progressive collapse performance of the substructure and the catenary mechanism when the beam-column stiffness ratio is between 0.6-1.1. The side column axial compression ratio has little effect on the proportion of different mechanism resistance, but it can affect the bearing capacity of the composite beam-column substructure. The composite beam-column substructure exerts the best anti-progressive collapse performance when the side column axial compression ratio is 0.3.