大跨曲线斜拉桥Π形主梁分析方法研究

Study of Analytical Methods forΠ-shaped Main Girder of Long-Span Curved Cable-Stayed Bridge

为获得适用于大跨曲线混凝土斜拉桥Π形主梁受力分析的实用方法,以刚果共和国布拉柴维尔滨河大道桥为研究对象,综合考虑施工过程中新梁段的浇筑、预应力筋张拉、混凝土收缩徐变等影响,分别采用梁-板混合有限元法及杆系有限元法建立空间有限元模型,对斜拉索索力、支座反力、主梁内力进行计算对比。结果表明:曲线斜拉桥主梁"弯扭耦合"效应明显,由此导致的边墩支座脱空问题应引起重视;梁-板混合有限元方法能够反映实际工程的主要力学行为和特点,特别适合空间复杂受力的Π形截面曲线梁的受力分析。最后通过缩尺模型试验,验证了该方法用于实际桥梁受力分析的可行性。研究结果可为大跨Π形主梁曲线斜拉桥的设计及施工提供参考。

To obtain pragmatic approaches to analyze the complex load bearing mechanism of theΠ-shaped main girder of the long-span curved concrete cable-stayed bridge,the Brazaville Riverside Avenue Bridge in Republic of Cango was cited as an example for the study.The influences of the casting of the new girder sections,prestressing tendons tensioning and the concrete shrinkage and creep during the construction were considered.The beam-plate mixed finite element model and link finite element model of the bridge were established,to calculate and analyze the cable forces,reaction forces of the bearings and internal forces in the main girder.The results show that the bending-torsion coupling effects in the main girder of the curved cable-stayed bridge were distinct,and the problem of side-pier bearing disconnected with the girder induced should be given enough attention.The beam-plate mixed finite element model can reflect the main load bearing behaviors and characteristics of the real project,which is especially applicable to the load bearing analysis of the curved girder that hasΠcross section and complex spatial load bearing performance.Finally,the scale-down model test was conducted to verify the feasibility of using this method to the load bearing analysis of real bridge.The findings of this study can provide references for the design and construction of long-span curved bridge withΠ-shaped main girder.