曲线波形钢腹板组合箱梁空间受力性能研究

Study on spatial mechanical behavior of curved composite box girder with corrugated steel webs

钢底板-波形钢腹板组合箱梁具有承载能力高、抗裂性能好、结构自重轻、施工便捷等特点,在曲线桥中具有应用推广潜力。针对曲线波形钢腹板组合箱梁的空间受力性能,开展了双箱单室曲线波形钢腹板组合箱梁的静力试验,考察其在弹性工况下的抗弯刚度、应变分布、支座反力等关键受力性能。结果表明:外弧侧加载工况下结构扭转效应更明显;跨中截面正应变分布符合“拟平截面假定”;外弧侧加载可能导致支座脱空。在试验研究基础上,建立了适用于多箱单室曲线波形钢腹板组合梁桥的精细化有限元模型,通过参数分析推导了荷载横向分布系数的实用计算公式。与数值分析结果的对比表明:提出的经验公式具有较高的计算精度,有95%以上桥梁算例的计算误差小于10%,相比于AASHTO LRFD规范公式能够更加准确地反映大曲率组合梁的空间受力特征,可为此类桥型的简化分析和工程设计提供参考。

The composite box girder with corrugated steel webs and steel bottom plates has the advantages of high bearing capacity,good crack resistance,light self-weight,and convenient construction,and thereby has a promising potential for application in curved bridges.The static tests were conducted on the spatial mechanical behavior of curved composite double-box girders with corrugated steel webs.The key mechanical behavior including the bending stiffness,strain distribution,and support reaction force under elastic conditions were investigated.The results indicate that the outer arc side loading leads to a more obvious torsion effect.The normal strain distribution of the mid-span section conforms to the quasi-flat section assumption.Bearing disengagement may occur when the outer arc side is loaded.Based on experimental research,an elaborate finite element model for curved composite multi-box girder bridges with corrugated steel webs was established.The practical formula for calculating the load transverse distribution factor was derived by parametric analysis.The comparison with the numerical analysis results shows that the proposed empirical formula has high calculation accuracy,and the calculation error of more than 95%of the bridges is less than 10%.Compared with the AASHTO LRFD specification,the proposed formula can more accurately reflect the spatial mechanical characteristics of large curvature bridges,which can provide a reference for the simplified analysis and engineering design of such bridges.