桥梁钢 混结合段试验模型加载多目标优化

混合式叠合梁斜拉桥钢-混结合段的受力分析,通常采用有限元分析与试验相结合的方法.模型试验的加载方式与加载力,需要通过模型设计,并保证其与实桥受力状态一致来确定.以红水河大桥为例,建立了实桥结合段有限元模型并对其加载,提取其中关键截面内力,换算得到对应缩尺模型位置的内力;选取钢-混结合面处的内力作为目标值,加载位置与荷载作为优化变量,其他各截面内力作为约束条件,建立新的数学模型;结合遗传算法对该数学模型进行优化,获得了最优的加载方案.

Multi-objective Optimization of Model Loading Test forSteel-concrete Composite Section of Bridge

The force analysis of the steel-concrete composite segment of the hybrid composite beam cable-stayed bridge is usually combined with the finite element analysis and the test. For the test analysis of the joint section, the internal force of steel-concrete composite section obtained by the scale test loading scheme can not effectively reflect the internal force distribution of the corresponding position of the real bridge. Taking the Hongshui River Bridge as an example, the finite element model of the real bridge joint section is established and loaded. The internal force of the key section is extracted from the finite element model, and the internal force corresponding to the position of the scale model is converted. The internal force at the steel-concrete composite section is selected as the target value. The loading position and load are used as optimization variables, and the internal forces of other sections are used as constraints to establish a new mathematical model. The mathematical model is optimized by genetic algorithm to obtain the optimal loading scheme. The scale model is loaded by this scheme, and the stress distribution at the key position of the model is measured. The comparison with the finite element results shows that the internal force distribution is consistent with the internal force distribution of the corresponding position of the real bridge, and the effectiveness of the method is verified.