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针对体外预应力混凝土箱梁桥中的角隅矩形齿块锚固区,研究了拉压杆模型构形及其配筋设计方法。首先通过应力场分析、传力路径的拓扑优化找形以及抗剪钢筋作用机理分析,揭示了产生局部拉应力集中的四种作用效应以及锚固力由承压面经角隅齿块向壁板传递过程中的两种荷载传递机制。同时,利用有限元数值分析结果,拟合出锚固力在箱梁腹板与翼板间分配比例的计算公式,在此基础上,构建两个平面内的精细化桁式拉压杆模型以恰当反映角隅齿块各部位受拉、受压、受剪规律及配筋设计需求。以所提出的拉压杆模型为基础,并结合美国AASHTO桥梁设计规范,给出了角隅矩形齿块锚固区的配筋设计方法,设计示例表明该方法具有良好的实用性,可供工程设计参考。
According to the anchorage zone of corner rectangular gear box in external prestressed concrete box girder bridge, the configuration of tension and compression rod model and the design method of reinforcement are studied. First of all, through the analysis of stress field, topological optimization and force-finding of force transmission path and analysis of the mechanism of shear reinforcement, four effects of local tensile stress concentration and the anchoring force are transmitted from the pressure-bearing surface to the siding Two load transfer mechanisms in the process. At the same time, by using the numerical results of finite element analysis, the formula for calculating the distribution ratio of anchorage force between the box girder webs and the wings is obtained. On this basis, two in-plane refined truss tension and compression bar models are constructed Reflect the various parts of the corner block tension, compression, shear and reinforcement design requirements. Based on the proposed tension-compression bar model and combined with the design specifications of AASHTO Bridge in the United States, the design method for the reinforcement design of the anchorage zone of corner block is given. The design example shows that the method has good practicability and can be used in engineering design reference.