钢-混组合梁不同施工方案结构分析研究

Structural Analysis and Research on Different Construction Schemes of Steel-Concrete Composite Beams

摘要:

随着人们对桥梁美观及施工期间低影响的要求逐步提升，钢—混组合梁在城市桥梁建设中被广泛应用。钢-混组合梁由于两阶段受力特点，不同的施工方案对其成桥后的结构受力影响较大。以沪杭公路跨线桥为工程实例，通过有限元软件MIDAS Civil对58 m钢—混组合梁进行不同施工方案仿真分析，对比分析了不同临时支撑布置、施工顺序及落梁拼接方案对结构受力及挠度的影响。结果表明：桥跨范围内设置临时支撑可显著改善钢梁应力及成桥挠度，基本组合下钢梁顶缘拉应力能降低约35%，成桥后的挠度减少约33%；先施工完桥面附属再拆除临时支撑对结构应力及挠度改善有限；先拼接后临时撑上落梁方案在结构受力及挠度上均略微优于先落梁后拼接方案。

Abstract:

With the gradual increase in requirements for bridge aesthetics and low environmental impact during construction, the steel-concrete composite beams have been widely applied in urban bridge construction. Due to the two-stage stress characteristics of steel-concrete composite beams, the different construction schemes have a significant impact on the structural stress of the completed bridge. Taking the Shanghai-Hangzhou Highway Overpass Bridge as an engineering case, the 58-m steel-concrete composite beam is simulated and analyzed for different construction schemes through the finite element software MIDAS Civil. The effects of different temporary support layouts, construction sequences and beam-splicing schemes during lowering on the structural stress and deflection are compared and analyzed. The results show that arranging the temporary supports within the scope of bridge span can significantly improve the steel beam stress and completed bridge deflection. The tensile stress at the top edge of the steel beam under basic combinations can be reduced by approximately 35%, and the deflection of the completed bridge is reduced by about 33%. Completing the construction of bridge deck appurtenances before removing temporary supports has limited improvement on structural stress and deflection. The scheme of splicing first then lowering on temporary supports is slightly superior to the scheme of lowering first then splicing in terms of structural stress and deflection.