钢管桁架梁拱组合体系桥成桥索力优化

Optimization of Cable Force of Steel Pipe Truss Girder Arch Composite Bridge

采用有约束的最小能量法,以拱肋与主梁的弯曲、拉压应变能之和为目标函数,以吊杆张拉力为变量,制定能够契合优化目标的索力、关心截面位移以及内力的约束条件,通过建立优化模型来求解最优的成桥索力.基于优化模型,以80 m下承式单索面钢管桁架梁拱组合体系桥为工程实例,通过编制Matlab程序对索力进行小幅度优化使结构达到良好的成桥状态.结果表明:有约束的最小能量法求得的成桥索力分布趋势更符合实际,优化索力作用下主梁以及拱脚处的挠度、弯矩较设计值均有所减小.

By using the constrained minimum energy method,taking the sum of bending and tension strain energy of arch rib and beam as the objective function and the tension force of suspender as the variable,the constraint conditions of cable force,section displacement and internal force which can fit the optimization goal are formulated.Based on the optimization model,an 80 m steel tube truss girder arch composite system bridge with single cable plane is taken as an engineering example and its cable force by compiling a Matlab program is optimized to achieve a good bridge state.The results show that the trend of cable force distribution obtained by the constrained minimum energy method is more practical,and the deflection and bending moment of the main beam and the arch foot are reduced compared with the design value under the optimized cable force.