桥梁空间分析中预应力效应分析方法研究

Study on method of simulating spatial effect of prestressing force in bridge

预应力技术在桥梁中的广泛使用,使得桥梁结构受力状况复杂,对预应力混凝土桥梁进行空间分析是必要的;但由于预应力筋数量庞大且形状复杂,对预应力空间效应的模拟是预应力混凝土桥梁空间分析的难点。从预应力筋的实际作用机理出发,提出在预应力张拉阶段用等效节点荷载来模拟预应力对结构的作用;而在预应力管道灌浆后,将预应力筋作为结构的一部分,用实体退化单元进行结构分析,并用两算例对本文的方法进行了验证。结果表明,该方法能真正模拟预应力的空间效应,可用于预应力混凝土桥的空间分析。

With extensive use of prestressing force, the stress state of bridge structure becomes more complex, and it is necessary to analyze the bridge structure with three-dimensioned method. But for prestressed reinforcement＇s number and its shape, it is difficult to simulate the spatial effect of prestressing force. Based on prestressing force＇s mechanism, it was proposed that equivalent node load was used to simulate its spatial effect during tensing, and that degenerated solid element was employed to take prestressed reinforcement as a part of structure and to analyze structure after grouting. The method discussed in the paper was confirmed by two examples. The result of analysis shows that this method can really simulate the spatial effect of prestressing force, and can be used to three-dimensioned analysis of prestressed concrete bridge.