昌平轻轨钢-混凝土结合连续刚构桥设计

Design of Steel-Concrete Composite Continuous Rigid Frame Bridge on Changping Light Railway

轨道交通昌平线高架区间跨线桥采用两联桥跨布置为(37+60+79+42.5)m及(42.5+79+42.5)m的钢-混凝土结合连续刚构方案,本桥具有跨度大、曲线半径小、地震烈度高、桥下既有线众多等特点,设计控制因素较多。介绍该桥的方案选择、结构设计、主梁有效宽度计算以及墩梁固结段的处理,并针对连续梁负弯矩区混凝土桥面板受力问题,提出预制桥面板、预加静载法、施加纵向预应力、滞后结合、高配筋率等多种处理方法,对其效果做出综合比较,以确定最终施工方案。

Consisting of two multi-span units of （ 37＋60＋79＋42.5 ）-m and （ 42.5＋79＋42.5 ）-m, a steel-concrete composite continuous rigid frame was used for the viaduct bridge on Changping line of Beijing urban rail transit to cross above existing railway lines. The bridge is characterized by large bridge span, small curve radius, high earthquake intensity, many existing railway lines under the bridge, etc.;and so the design for it was dominated by many factors. This paper introduced the scheme selection, structure design, calculation of effective width of main girder, and the treatment of the rigid connection zone between piers and girder. And then in order to solve the stress problem in concrete bridge deck in the negative bending moment zone of the continuous girder, a variety of treatment methods were proposed in this paper, such as using prefabricated bridge deck, static pre-loading, longitudinal pre-stressing, hysteresis effect, high reinforcement ratio and so on. Furthermore, the effects of treatment measures were comprehensively compared with each other in this paper so as to determine the final construction scheme.