钢-混凝土组合梁加宽旧桥的实测与理论分析

Field Test and Theoretic Analysis of an Old Bridge Widened with Steel-Concrete Composite Beams

为研究采用钢-混凝土组合梁加宽后的重庆牛儿河桥的工作性能及其跨中横向分布系数的计算方法,对其进行现场实测,并建立三维弹性有限元模型模拟实桥。研究结果表明:组合梁能够与旧桥共同工作,组合梁加宽旧桥整体性良好;采用刚性横梁法计算旧桥加宽后的跨中横向分布系数,计算结果与实测结果、有限元结果吻合良好。采用有限元方法对钢-混凝土组合梁与旧桥之间的跨中横梁数量进行参数分析,结果表明跨中横梁对跨中横向分布系数的影响可忽略。

The field test is made for the old Chongqing Niuer River Bridge after it was widened with steel-concrete composite beams and a three-dimensional elastic finite element model is established to model the tested bridge in order to study the working performance and the calculation method for the midspan lateral distribution factors （LDF） of the bridge. It is found from the study that the composite beams can work together with the old bridge and the bridge after widened with the composite beams performs well as an integrity. The rigid transverse beam method is used to calculate the midspan LDF of the bridge and the calculation agrees well with the results of field test and finite element method. The finite element method is then used to conduct the parametric analysis of the numbers of the intermediate diaphragms between the composite beams and the old bridge and it is further found that the diaphragms have negligible effect on the LDF.