体外预应力筋不同有限元模型的比较分析

Comparison and analysis on external prestressing tendon using different finite element models

为了简化大跨径节段施工体外预应力桥梁的计算分析,对常规带刚臂杆单元模型、多段多节点杆单元模型及等效节点荷载模型(不计体外预应力筋刚度)等体外预应力梁中体外预应力筋的有限元分析模型进行了简单介绍。并基于体外预应力梁中体外筋与转向块之间可自由滑移而导致体外筋为常应变构件的受力特点,结合已有的桥梁线弹性分析程序,提出基于迭代的带刚臂杆单元分析模型,并研制了相应的程序,对一简支体外预应力混凝土梁进行了计算。研究结果表明:该模型的计算精度高,其程序设计及与现有程序的连接更为便捷。

In order to simply the calculation analysis of externally prestressed concrete long-span bridge segmental construction,a number of works were reported for the finite model of concrete beams prestressed with external tendons,the effects of external tendons are expressed by equivalent nodal loads of the beam element(the stiffness of external tendons are neglected),truss elements with rigid arms or multi segement-node in general,the principles of the above calculation models are briefly introduced.A numerical model based on the external tendons are members for the normally elastic strain caused by the free sliding between external tendons and deviators incorporating the existing line-elastic analysis programs is established.The analysis is capable of calculating long-span prestressed bridge with external tendons by iterative algorithm.Some numerical examples are presented.The results show that the model has obvious advantages of higher calculation accuracy,more convenient in programming and connecting with existing programs.