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针对体外预应力混凝土箱梁桥中的独立矩形齿块锚固区,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、裂缝分布模式试验验证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3种作用效应以及锚固力由承压面经独立齿块向壁板传递过程中2种荷载传递机制。在此基础上,提出了一种新的精细化桁式拉压杆模型,该模型能恰当反映独立齿块各部位受拉、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,给出了独立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。
Aiming at the independent rectangular gear block anchorage zone in external prestressed concrete box girder bridge, the configuration of the tension and compression rod model and the design method of reinforcement are studied. Firstly, through stress field analysis, topology optimization of force transmission path, shape verification, test of crack distribution mode and analysis of mechanism of shear reinforcement, three kinds of effect of local tensile stress concentration and anchoring force are revealed. Block to the wall of the process of transferring two kinds of load transfer mechanism. On this basis, a new refinement truss tension and compression rod model is proposed, which can properly reflect the tension, compression, shear and reinforcement requirements of various parts of an independent tooth block. Based on the proposed tension-compression bar model and combined with the American AASHTO bridge design code, the design method of reinforcement for the anchorage zone of an independent rectangular tooth block is given. The design examples show that the method has good practicability and can be used for engineering design reference .