非常规荷载作用下泥石流板式渡槽的优化设计

跨径为16 m的装配式渡槽施工阶段张拉预应力钢筋后,截面下缘压应力超过规范规定的界限,采用了分阶段张拉预应力钢筋的方法,以现行规范为依据,以空心板的高度和各阶段预应力筋的面积为变量,以施工阶段和使用阶段混凝土应力限制为约束条件,建立了单位长度空心板的造价目标函数。并利用Matlab语言,编制了遗传算法程序进行了优化分析。优化结果表明,优化设计的截面尺寸与实际设计的相比,截面高度大一些,但总造价却比实际设计的要减小16%,优化设计收到了良好的经济效益。最后,按照优化设计过程提出了一些施工注意事项,为以后类似的设计提供了参考。

Optimum Design of Debris Flow Slab Type of Aqueduct Subjected to Abnormal Loads

During the construction of 16m span assembled debris flow aqueduct,the underlayer fringe stress of the cross-section is too much big after tensioning the prestressed reinforcements,which exceed the limit of standard.The prestressed method with stage tensions is adopted to design.According to the current standard,taking the height of hollow slab and areas of the prestressed bar of every stages as variables,and taking the concrete stress limits at construction stage and using stage as restraint conditions,the cost objective function of unit length hollow slab is established.Using Matlab language,the genetic algorithm procedures is compiled for optimum design.The results of optimization show that,comparing with the actual design,the section height of the optimum design is bigger,while the total cost is lower by 16%,which means a good economic benefits is obtained.According to the process of the optimum design,some attentions are put forward for the construction,which may be referenced for the similar design.