梁拱组合体系桥梁空间效应与关键构造设计方法研究

Spatial Mechanical Effects and Key Component Designs of Girder-arch Combined Bridges

梁拱组合体系桥梁通过对主梁与拱圈(肋)施加预应力,从而取消空腹部分的立柱及斜撑,使得整个结构轻巧美观,但也由此带来显著的结构受力空间效应。以扬州市观潮路跨古运河大桥(宽体梁拱组合体系桥梁)为工程背景,利用大型通用有限元程序ANSYS建立三维实体单元模型,对该桥的施工体系转化过程进行精细化数值模拟,重点分析其空间结构受力特征。通过改变关键设计参数取值(包括宽跨比、截面形式、横向连接方式等),利用参数分析手段对该桥运营阶段的空间力学效应进行分析,明确各参数与空间效应之间的关联。针对梁拱组合体系桥梁的关键构造空腹三角区域,提出拱梁刚度比的设计参数指标,得到该指标对结构空间受力的影响。研究结果为梁拱组合体系桥梁的结构安全性与设计合理性提出了更明确的理论解释与优化依据。

By prestressing the main girder and arch ring,there are no columns and inclined struts designed in the hollow area of girder-arch combined bridge system,which makes the bridge attractive but also with remarkable 3D effects.Taking the Yangzhou Guanchaolu Kuagu canal bridge(girder-arch combined bridge system)as an example in the present study,the system change and construction process were simulated by the 3D solid elements in the ANSYS program with the focus on the spatial mechanical effects.By changing the values of the key design parameters(ratio of width to span,cross-section,transverse connection,etc.),the spatial mechanical effects of the girder-arch combined bridges were investigated based on the parametric study.The relationship between these design parameters and spatial mechanical effects was accordingly determined.The stiffness ratio of the arch to girder was further proposed as a design criterion for the key component of the hollow triangle area between the girder and arch.Its influence on the spatial mechanical effects was also obtained.The results can provide more specific theoretical explanation and optimization basis for the safety and rationality of the girder-arch combined bridges.