混合梁跨度合理布置对结构内力的影响研究

Research on Influence of Reasonable Arrangement of Span of Hybrid Beam on Structure Internal Force

混合梁桥能充分发挥混凝土和钢材的性能,提升跨越能力及经济性,但主跨跨径常因施工条件、经济性等因素所限,大多参照一般性原则进行设计,结构内力分布与跨度合理布置的关系易被忽视。为解决上述问题,基于位移法推导了三跨混合梁三处弯矩的理论解,以湖州长兴大桥为案例研究其跨度的最合理布置,结果表明:在一定范围内增大中跨与边跨长度比,并将中跨钢箱梁段与混凝土段长度比控制在0.3~0.5内,可使得桥的受力性能更为合理。

Hybrid beam bridges can give full play to the performance of concrete and steel and improve the span capacity and economical efficiency.However,the main span is often limited by construction conditions,economical efficiency and other factors,and most of them are designed with reference to general principles.The relationship between structural internal force distribution and reasonable arrangementof spanis ignored.In order to solve the above problems,the theoretical solutions of three bending moments of three span hybrid beam are derived based on the displacement method.Taking Huzhou Changxing bridge as an example,the most reasonable arrangement of its span is studied.The results show that:increasing the length ratio of middle span to side span within a certain range and controlling the length ratio of middle span steel box beam section to concrete section within 0.3-0.5 can make the mechanical performance of the bridge more reasonable.