大跨度斜拉桥施工过程索力和线形双控研究

为了使斜拉桥在成桥后达到合理状态,必须拟定合理的施工状态,即在施工过程中使斜拉索力和结构位形同时达到理想状态.采用一阶最优化计算方法,以成桥后结构的弯曲应变能和主梁的线形为目标函数,以斜拉索的初始张拉力和主梁节段的预抛高值为设计变量,建立了斜拉桥施工控制的空间非线性有限元分析模型,并以某大跨度预应力混凝土斜拉桥为例,模拟了混凝土主梁的悬臂浇筑过程.结果表明,该方法可使成桥后主梁的线形和结构的内力得到合理控制,从而可有效地确定斜拉桥的合理施工状态.

Cable prestress and alignment double control during construction of large-span cable-stayed bridges

Rational construction state,i.e.the cable prestress and structure alignment reach perfect condition simultaneously,should be defined,so that the cable-stayed bridge can reach rational state after the bridge construction.By use of the first order optimization calculation method,a nonlinear spatial finite element model for cable-stayed bridge construction control was developed with the bending strain energy of the bridge structure after construction and the alignment of the main girder taken as the objective functions and the initial tensile force of stayed cables and the prearranged height of main girder sections taken as the design variables.A case study was performed on a large-span cable-stayed prestressed concrete bridge,and the simulation of the pouring process of the cantilever of main concrete girders with the method shows that the method can effectively control the alignment of the main girders and the internal force of the bridge structure after the bridge construction,and thus it can efficiently determine the rational construction state of the cable-stayed bridge.