混合梁刚构桥受力计算方法与合理结构体系研究

Mechanical Calculation and Rational Structural System of Hybrid Beam Rigid Frame Bridge

摘要:

在传统混凝土刚构桥基础上把主跨跨中的一部分改为钢梁而形成的混合梁刚构桥有效实现了梁桥在跨度上的突破及结构性能的改善，成为非常有应用前景的一种桥梁结构形式，并在实际工程中越来越被广泛应用。为探究三跨钢-混凝土混合梁刚构桥结构体系的合理布置和受力性能的简化计算方法，推导了混合梁刚构桥在施工阶段及成桥阶段的简化力学模型，并通过有限元方法和实桥测试验证了简化力学模型的正确性。基于简化力学模型，以控制截面内力为目标函数，计算分析了边跨与中跨长度之比λ、钢梁长度与主跨长度之比μ（或结合段位置参数）对混合梁刚构桥受力性能的影响。研究结果表明，基于结构的合理受力性能，得到了λ和μ的合理取值范围，综合考虑桥梁施工和运营中的风险，建议λ取0.4、μ取0.4~0.5，可作为混合梁刚构桥的设计参考。

关键词:混合梁刚构桥;简化模型;结构体系;结合段位置;边中跨比

Abstract:

On the basis of traditional concrete rigid frame bridge， the hybrid beam rigid frame bridge formed by replacing a part of the main span with steel beam has effectively achieved a breakthrough in the span of the beam bridge and an improvement in structural performance. So， it has become a very promising bridge structure and has been more and more widely applied in actual engineering. In order to explore the reasonable arrangement and simplified calculation method of the mechanical performance of the three-span steel-concrete hybrid beam rigid frame bridge structure system， the simplified mechanical model during construction and completion was derived. The calculation precision of the model was verified by the finite element models and testing results of an actual project. Based on the model， taking the internal forces of the control sections as the objective functions， the effects of λ （the ratio of side-span and mid-span） and μ （the ratio of the steel beam length and main span length or the position parameter of the steel-concrete composite segment ） on the mechanical performance of the hybrid beam rigid frame bridge were calculated and analyzed. The research results show that based on the reasonable mechanical performance of the structure， the reasonable value range of λ and μ is obtained. Considering the risk in the construction and operation of the bridge， it is suggested that λ takes 0.4 and μ takes 0.4 ~ 0.5， which can be used as the design reference of the hybrid beam rigid frame bridge.

Key words:hybrid beam rigid frame bridge;simplified model;structural system;position of steel-concrete composite segment;the ratio of side-span and main-span