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针对钢箱梁斜拉桥成桥状态的优化问题,以钢箱梁斜拉桥主梁和桥塔的弯曲能量之和为目标函数,以主梁和桥塔位移、应力、斜拉索索力及其均匀性等为约束条件,建立钢箱梁斜拉桥成桥状态优化的二次规划数学模型,并采用乘子-Newton优化算法进行求解;结合该方法和有限元方法对国内某座大跨径独塔钢箱梁斜拉桥的成桥状态进行了优化,并与无约束最小弯曲能量法及刚性支承连续梁法的优化结果进行了对比。研究结果表明:该方法优化所得结构位移、内力、应力及索力与其余两种方法优化结果的最大相对误差分别为21mm、127.29%(16 194kN·m)、154.21%(4.58MPa)以及22.51%(346kN);该方法所得成桥状态下,主梁线形平顺,内力及上下缘应力分布均匀,桥塔塔顶向边跨有一定的预偏,且为全截面受压状态,斜拉索索力随斜拉索长度的增长均匀递增,过渡墩与辅助墩的支承反力均为正值,具备一定的压力储备;该方法简便、有效、实用性强,可避免采用传统方法时,人为调索的随意性,可方便地获得钢箱梁斜拉桥的合理成桥状态。
Aiming at the optimization problem of the bridge state of steel box girder cable-stayed bridge, taking the sum of bending energy of main girder and bridge tower of steel box-girder cable-stayed bridge as objective function, taking the displacement and stress of main girder and bridge tower, And its uniformity as the constraint condition, the quadratic programming mathematic model of steel box girder cable-stayed bridge is established and solved by multiplier-Nwton optimization algorithm. Combining with this method and the finite element method, The condition of bridge construction of the cable-stayed bridge with diameter-single tower was optimized and compared with the results of the unconstrained minimum bending energy method and the rigid support continuous beam method. The results show that the maximum relative errors of optimization results obtained by this method are 21mm, 127.29% (16 194kN · m), 154.21% (4.58MPa) and 22.51% (346 kN). Under the condition of bridge construction, the main beam has a smooth line shape and uniform stress distribution at the upper and lower edges. There is a certain pre-deflection across the top of the bridge tower and the cross-section is under compression. The cable tension With the increase of the length of the stay cable, the supporting reaction force between the transition pier and the auxiliary pier is positive and has a certain pressure reserve. The method is simple, effective and practical, which can avoid manual adjustment when the traditional method is adopted Of randomness, can be easily obtained steel box girder cable-stayed bridge into a reasonable state of the bridge.