在役预应力混凝土斜拉桥的结构状态模拟

Simulation on structural state of PC cable-stayed bridges in service

结构状态模拟是加固设计和加固后评估的前提和基础,为了提出在役预应力混凝土斜拉桥维修加固前基准计算模型的建立方法,以天津永和大桥为例,从原桥施工过程的模拟出发,依据桥面线形、索力及塔顶偏位等结构指标的检测结果,通过分析大桥服役期内各种因素对结构性能的影响,确定相应的误差调整方法,提出相关的简化或近似处理手段,使模拟计算结果逼近于当前的检测结果。模拟结果表明:计算选取的结构刚度参数合理,计算桥面线形与检测结果误差不超过±5 cm,计算索力与检测索力误差不超过±3%,计算塔顶偏位与检测值较为接近。

The simulation on structural state is the precondition or basis for strengthening design and post evaluation after strengthened in prestressed concrete cable stayed bridges.In order to present the method of establishing the baseline calculation model for strengthening an existing prestressed concrete cable stayed bridge,Yonghe Bridge in Tianjin is taken as an example.A FEM model is obtained to simulate its original state firstly.Then,according to its current detected results,such as the geometry of bridge deck,cable forces and the inclined displacement at the top of towers,some factors in service on structural performances are analyzed.Finally,a calculation error adjustment method is provided,and some simplification and approximation are introduced to make the calculation results consistent with the detected ones.Simulation calculation results show that selected theoretical structural rigidity is appropriate,and the error between the calculated geometry of bridge deck and the detected one is lower than ±5cm.Moreover,the error is not more than ±3% between each calculated cable forces and its corresponding detected one and the inclined displacement calculated at the top of towers is close to the detected data.