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在大跨径桥梁监控中,监控精度受诸多参数的影响,其中温度参数的影响较大,温度变化对桥梁结构的挠度和受力都将产生很大的影响,对桥梁监控中的温度应力进行研究显得尤为重要。笔者基于松弛法分析梁体的非线性温差应力,并与传统的理论计算方法进行比较,采用桥梁专用有限元软件MIDAS/Civil,按照设计的温度梯度变化进行模拟分析,求出温度应力作用的最不利位置,然后结合工程实践探究温度变化对桥梁的挠度和应力的影响。研究结果表明,采用松弛法分析的应力结果与传统的理论方法相比计算值较大,偏于安全。温度梯度荷载作用下对成桥后桥梁的跨中影响较大,上缘出现压应力,下缘出现拉应力,悬臂施工状态的桥梁在温度梯度荷载作用下1﹟块截面处上顶板出现较大的压应力,下底板压应力较小。因此,在监控中必须充分考虑温度应力对桥梁产生的影响,这样才能确保结构受力的安全,得出更合理的设计线形,也可以为施工设计提供参考。
In long-span bridge monitoring, the monitoring accuracy is affected by many parameters, of which temperature parameters have a greater impact on the bridge structure deflection and stress will have a great impact on the bridge temperature stress monitoring Research is particularly important. Based on the relaxation method, the author analyzes the nonlinear thermal stress of the beam body and compares it with the traditional theoretical calculation method. The finite element software MIDAS / Civil for bridge is used to simulate and analyze the temperature gradient according to the designed temperature gradient. Unfavorable position, and then combined with engineering practice to explore the impact of temperature changes on the bridge deflection and stress. The results show that the stress results obtained by the relaxation method are more calculated and safer than the traditional theoretical methods. Under the effect of temperature gradient loading, the influence of the bridge on the bridge is greater than that of the bridge. The upper edge of the bridge has compressive stress and the lower edge of the bridge has tensile stress. When the bridge is under cantilever construction, Of the compressive stress, under the floor compressive stress smaller. Therefore, the monitoring must take full account of the impact of temperature stress on the bridge, so as to ensure the safety of the structure stress, draw a more reasonable design line, also can provide reference for the construction design.