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体外预应力技术是加固既有预应力混凝土桥梁最有效的方法之一,可大幅提高原桥刚度及承载能力并克服其他加固方法中难以克服的二次受力问题。利用结构变形前后的几何关系,提出了在车道荷载作用下三折线布筋形式的体外预应力应力增量计算公式,进而推导了单折线、直线布筋形式的体外预应力增量的计算公式,计算公式的物理意义明确,可计算不同荷载下的体外预应力应力增量。通过一座预应力混凝土简支T梁的加固设计实例,计算了体外预应力在车道荷载作用下的应力增量及施工阶段、使用阶段梁的上下缘混凝土应力,为简支梁的体外预应力加固工程提供了理论技术支持。
External prestressing technology is one of the most effective ways to reinforce an existing prestressed concrete bridge, which can greatly improve the stiffness and bearing capacity of the original bridge and overcome the secondary force problems that are difficult to overcome in other reinforcement methods. Based on the geometric relation before and after the deformation, the calculation formula of external prestressing stress increment of the tri-fold wire reinforcement under the action of the lane load is proposed, and then the formulas for calculating the external prestressing increment of single-fold line and straight- The physical meaning of the calculation formula is clear, and the prestress increment in vitro can be calculated under different loads. Through an example of reinforcement design of a prestressed concrete simply supported T-beam, the increment of stress of external prestressing under the load of the lane and the construction phase are calculated. The concrete stress at the upper and lower edges of the beam is used to reinforce the prestressed concrete beam in vitro Engineering provides theoretical and technical support.