海宁桥拓宽改建工程方案设计浅析

Brief Analysis on Scheme of Haining Bridge Widening Reconstruction Project

预应力空心板梁支点抗剪较跨中抗弯的安全储备低,超载导致板端腹板斜裂缝宽度超标,方案考虑拆除与新建衔接,采用部分利用中幅桥并拓宽改建的设计方案。桥梁拆除为危大工程,采用汽车荷载与吊车荷载加载效率比较法检算跨中弯矩、设置横向分配梁使得板梁可承受吊车支点产生的较大剪力、控制盖梁拆除时边柱不平衡弯矩,进行拆建、吊装期间桥梁结构在最不利工况下的承载能力设计。

The fulcrum shear resistance of prestressed hollow slab beam has lower safety stock than one of the midspan bending resistance.The overload results in the oblique crack width of the web at slab end exceed the standard.The scheme considers the connection between the demolition and new construction.The design scheme is to partially use the middle span bridge,and widen and reconstruct.The bridge demolition is the large dangerous project.The comparison method of motor vehicle loading and crane loading efficiency is used to check and calculate the midspan moment.The setup of transverse distribution beam makes the slab beam able to bear the larger shearing force generated by the crane fulcrum.The imbalance bending moment of side column is controlled during the demolition of bent cap.The bearing capacity of bridge structure during the demolition,construction and hoisting under the worst construction condition is designed.