四跨组合梁桥不同支座回落方式力学及经济性能分析

Comparison and Analysis on Mechanics and Economic Performance of Four-span Composite Beam Bridge under Different Bearing Dropping Modes

中支点回落可以有效降低负弯矩区桥面板裂缝。以一座(32+45+45+32)m的槽形组合梁为背景,通过杆系有限元分析,比较了多种支座回落方式对钢梁受力和钢材用量的影响。结果表明,中支点钢梁顶板板厚变化对裂缝影响不大;先落边中支座会使中中支点钢梁受力不利;三个中支点同时回落,钢梁受力更加合理,钢材造价较无支座回落而增加桥面板配筋降低近27万元。

The bridge deck crack of hogging moment region can be effectively reduced by the central bearing-point dropping mode. Based on the background of a 32 m+45 m+45 m+32 m sulciform composite beam bridge, this article compares the influences of the different bearing dropping modes on the stress of steel beam and the amount of steel through the bar system finite element analysis. The result shows that thickness change of steel beam top plate at the central bearing point has little influence on crack. The central bearing firstly dropping at the side will make the stress of steel beam unfavorable. The stress of steel beam will be more reasonable if three central bearings drop at the same time. The cost of steel will be reduced by RMB 270 000 yuan if comparison with no bearing dropping to increase the reinforcement of bridge deck.