大跨钢-混凝土连续组合箱梁桥双重组合作用

为研究双重组合作用对大跨钢-混凝土连续组合箱梁桥受力性能的影响,通过对潍坊市跨济青高速立交桥现场静载试验研究,采用有限元方法对2种模型计算结果及现场实测结果进行比较分析,并对双重组合箱梁下层混凝土板的长度与主跨长度之比和混凝土板厚度与钢梁底板厚度之比2个变量进行参数分析。研究结果表明:双重组合箱梁下层混凝土板有效降低钢梁下翼缘的应力;考虑双重组合作用后,连续组合梁桥结构刚度及支点负弯矩略有增加,中跨跨中挠度及正弯矩略有减小,最大幅度不大于10%。

Double composite action of large-span steel-concrete composite continuous box-girder bridges

In this paper field load tests of an overpass across the Jinan-Qingdao highway in the city of Weifang are conducted,and then the results of field tests and two finite element models are compared.The models are then used for parameters analyses of the ratio of the length of the lower concrete slab in the double composite box-girder to the major span and the ratio of the concrete slab thickness to the steel plate thickness.The study shows that the lower concrete slab in a double composite box-girder effectively reduces the stresses in the lower flange of the steel girder.Also,the double composite action slightly increases the hogging moment of the continuous composite girder bridge and the bridge stiffness with slight reductions of the sagging moment and the mid-span deflection bridge.The most changes are not more than 10% for commonly used lengths and thicknesses of the lower concrete slab.