基于反演理论在役连续刚构桥有效预应力识别

Effective pre-stress identification of the continuous rigid frame bridge in service based on inversion theory

由于受环境、气候、荷载及其他外在因素的共同影响,施加于桥梁结构的预应力也随之发生变化,准确掌握其内部真实的应力状态对保证桥梁的安全运营至关重要。针对这一问题,以反演理论为基础,依据桥梁服役期间结构变位的实际监测结果,由位移反分析法得到了不同时间点梁体内存在的有效预应力数值。以某一预应力混凝土连续刚构桥为例,通过反分析得到的有效预应力为参数,重新建立有限元计算模型,分析了在设计荷载作用下梁体强度及刚度的变化情况。理论结果与实测位移的对比表明,利用反分析法可以较为精确地预测服役期间桥梁内真实的预应力状态。

Due to the environment,climate,loads and other external factors,the pre-stress applied to the bridge is not constant.It is important for engineers to find out the accurate stress condition in order to ensure security of the bridge in service.To solve the problem mentioned above,according to actual monitoring displacement of the bridge in service at different time,the effective pre-stress is obtained by the displacement inversion method based on the inversion theory.Lastly,taking the pre-stressed concrete continuous rigid frame bridge for example,the finite element model with different effective pre-stress is established and the strength and stiffness are analyzed under design load.It is shown from the comparison results of analytical displacements and measured ones that the inverse method is an effective way to predict reasonable pre-stress for the bridge in service.