温度作用下钢桁拱桥活动支座工作性能评估方法研究

Research on Methods to Evaluate Service of Movable Bearings in Steel Truss Arch Bridge Under Thermal Effect

为准确判断钢桁拱桥活动支座服役期间的工作性能,对温度作用下活动支座工作性能评估方法进行研究。以某铁路钢桁拱桥为背景,分析梁体局部温度与支座纵向位移相关性的差异,推导钢桁梁支座纵向位移与温度梯度的关系式;分析支座摩阻力对支座纵向位移的影响,运用间隙迟滞非线性系统建立温致支座纵向位移滞回模型,进而提出用于评估活动支座工作性能的指标--间隙迟滞系统的参数C。采用现场监测数据对评估指标的可靠性进行验证。结果表明:评估指标(参数C)能够反映支座摩阻力的大小和支座纵向位移迟滞特性的强弱,C值增大,活动支座工作性能劣化,可以通过长期数据的积累实现活动支座性能劣化情况的识别。

Methods to evaluate the service of movable bearings in the steel truss arch bridge under thermal effect are studied.A real railway steel truss arch bridge is used as a case.The correlation between girder body local temperature and longitudinal displacement of bearings is analyzed,and the relationship between the longitudinal displacement of movable bearings and the temperature gradient is derived.The influence of friction force of bearings on the longitudinal displacement of bearings is analyzed.The temperature-induced longitudinal displacement hysteresis model of bearings was built up based on the gap hysteretic nonlinear system,subsequently,the index that is used to evaluate the service of the movable bearings is presented,which is named gap hysteretic system parameter C.The reliability of the evaluation index was verified by the measured data.As per the findings,the evaluation index(parameter C)can reflect the scale of the friction force of the bearing and the intensity of the longitudinal displacement hysteretic characteristics of the bearing.Bigger C indicates the degradation of the movable bearing.It is suggested that the long-term monitoring data be collected to identify the degradation extent of the movable bearing.