山区公路不对称连续刚构桥力学特性及加固方法研究

Mechanical Characteristics and Reinforcement Methods of Asymmetric Continuous Rigid Frame Bridges on Mountainous Highways

摘要:

由于受山区特殊地形的限制，需要把连续刚构桥设计成非对称的结构型式，为研究其结构特点，采用MIDAS Civil有限元软件建立模型，对位于山区公路上的某大跨度不对称连续刚构桥梁从内力、应力和位移等因素进行力学特性分析，研究各因素在恒载和活载作用下的变化规律。结合不对称连续刚构桥内力和位移的不同分布规律，对该类型桥梁出现的跨中下挠、箱底横向以及腹板斜向裂缝等病害进行成因分析，提出体外预应力加固方法，使桥梁中跨上、下缘应力均衡，降低竖向位移变化趋势，可为同类型桥梁加固提供借鉴。

Abstract:

Due to the limit of special terrain in mountainous areas, the continuous rigid-frame bridge needs to be designed into an asymmetric structural form. To research its structural characteristics, the MIDAS Civil finite element software is used to establish a model to analyze the mechanical properties of a long-span asymmetric continuous rigid-frame bridge on a mountainous highway from factors such as internal forces, stresses and displacements, and to study the variation laws of various factors under the action of dead load and live load. Combined with the different distribution laws of internal forces and displacements of the asymmetric continuous rigid-frame bridge, the causes of diseases such as mid-span deflection, transverse cracks at the bottom of the box, and diagonal cracks in the web are analyzed. The method of an external prestressing reinforcement is proposed to balance the stresses at the upper and lower edges of the mid-span of the bridge and reduce the trend of vertical displacement changes, which can provide a reference for the reinforcement of similar bridges.