分阶段施工合成箱梁湿接缝的合理宽度分析

Analysis of the Rational Width of Wet-Joint in the Composite Box Beam Built by Construction Stages

以广东省某分阶段施工合成箱梁桥为工程背景,通过改变翼缘板的宽度,计算预制主梁在张拉预应力时的稳定安全系数、跨中截面上下缘应力控制值,以及吊装就位时的安全系数.结果表明,主梁张拉时的主梁翼缘板宽度应大于1.20 m,即相应湿接缝的宽度应小于0.98 m;而主梁吊装时,应尽量保持吊绳竖直,相应湿接缝的宽度应小于等于0.98 m.最后,通过对试验模型进行张拉并进行有限元分析表明,跨中截面侧向位移和上拱值的有限元计算值均与实测值相接近,分别只有相差9.5%和2.9%.

Taking a box bridge in Guangdon province as engineering example, the buckling safety factor and the control stress at the bottom and the top of the mid-span section during tendon tensioning, and the buckling safety factor during lifting are calculated for the different width of the flange slab. The results show that the width of the flange slab should be greater than 1.2 m and corresponding width of the wet-joint should be less than 0. 98 m during tendon tensioning. The becket should be kept as vertically as possible during lifting, the corresponding width of the wet-joint should also be less than 0. 98 m. The model experiment and finite element method analysis show that the experimental results of the mid-span lateral displacement and mid-span upward deflection conform to calculational ones, the differences are 9. 5% and 2. 9% respectively.