大跨径连续钢混组合梁的设计及关键技术研究

Study on Design and Key Technology of Long-span Continuous Steel-concrete Composite Girder

摘要:

以汕头市国道G206跨线桥45.5 m+75 m+45.5 m连续钢混组合梁为背景，介绍大跨径钢混组合梁的构造设计及计算要点。通过对其施工方法、施工工序及墩顶负弯矩区域抗裂控制措施等关键技术研究，得出支架拆除时间、正弯矩区压重及预应力张拉对钢梁及桥面板内力有较大影响，组合梁设计时应充分考虑施工过程。最后综合考虑钢梁及面板受力情况，提出先张拉桥面板预应力后与钢梁叠合的方法是一种可用于大跨连续钢混组合梁较为合理的施工方法，值得推广与应用。

Abstract:

Based on the (45.5+75+45.5)-m continuous steel-concrete composite girder of an overpass bridge in the National Highway G206 in Shantou. the structural design and calculation essentials of a long-span steel-concrete composite girder are introduced. Through the study on the key technologies of its construction method, construction procedure and anti-crack control measures in negative bending moment area of pier top, it is concluded that the time of support removal, the pressure in positive bending moment area and the pre-stressing tension have the great influence on the internal forces of steel girder and bridge deck. The construction process should be fully considered in the design of composite girder. Finally, comprehensively considering the stress conditions of steel girder and concrete slab, it is proposed that the method of prestressing the tensioned bridge deck and then superposing with the steel girder is a reasonable construction method which can be used for long-span continuous steel-concrete composite girders, and it is worth popularizing and applying.