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对体外预应力混凝土结构的研究现状及数值模拟方法做出评价与分析。采用组合单元模拟钢筋混凝土结构,能全面考虑混凝土的开裂、塑性等问题;并推到一种体外预应力单元:在忽略摩擦的情况下,能够考虑体外筋在转向块处的滑移作用,从而对其变形与受力做出更准确的模拟。用以上两种单元对3片试验梁的三分点加载的全过程做了数值仿真分析,详细分析了荷载Q-挠度f曲线和挠度f-体外预应力增量σ曲线,明确指出加载曲线中各个转折点的物理意义,并对体外筋的极限应力增量取值问题提出了新的建议。通过计算值与试验数据对比分析,说明了采用组合单元和体外预应力单元共同模拟体外预应力混凝土结构的可行性和正确性,也同时为桥梁结构的数值计算模拟及设计提供了支持和经验。
The research status of external prestressed concrete structures and numerical simulation methods are evaluated and analyzed. The use of modular elements to simulate reinforced concrete structures can give full consideration to the cracking and plasticity of concrete, and it is pushed to an external prestressing unit that can consider the slip of in vitro tendons at the steering block, ignoring friction Make a more accurate simulation of its deformation and force. The above two kinds of units are used to simulate the whole process of the three-point loading of three test beams. The load Q-deflection f-curve and deflection f-external prestress increment sigma curve are analyzed in detail. It is clearly pointed out that in the loading curve The physical significance of each turning point, and put forward new suggestions on the value of ultimate stress increment of in vitro tendons. By comparing the calculated values with the experimental data, the feasibility and correctness of simulating the externally prestressed concrete structure with the combination of the unit and the prestressed external unit are demonstrated. The results also provide support and experience for the numerical simulation and design of the bridge structure.