跨高速公路的城市跨线桥方案设计研究

Study on Scheme Design of Urban Overpass Bridge Crossing Expressway

为得到某上跨高速公路的城市跨线桥最优设计方案,采用两阶段比选法,考虑现状高速的规模及远期改、扩建中的各种因素,从多个角度对桥梁跨径及桥梁结构形式进行比选论证,确定主跨65 m的三跨混凝土变高连续箱梁为最优推荐方案。对混凝土变高连续箱梁(36 m+65 m+36 m)进行有限元计算,结果表明,主梁各力学性能指标均满足规范要求。在此基础上设计出一种新型预制拼装混凝土防撞护栏用于该跨线桥上,缩短施工工期,且该护栏在现场施工时浇筑量小,施工质量更易控制。

To obtain the optimal design scheme of urban overpass bridge crossing some expressway,the two-stage comparison method is adopted.Considering the scale of the existing expressway and various factors in the longterm reconstruction&expansion,the bridge span&bridge structure form are compared&demonstrated from various angles,and the three-span concrete variable height continuous box girder with main span of 65 m is determined as the optimal recommended scheme.The finite element calculation of concrete variable height continuous box girder(36 m+65 m+36 m)is carried out.The results show that the mechanical properties of the main girder meet the requirements of the specifications.On this basis,a new type of precast concrete anti-collision guardrail is designed for the overpass bridge,which can shorten the construction period,and the pouring amount of the guardrail is small in the field construction,and the construction quality is easier to control.