赵川镇高架特大桥徐变研究

STUDY ON CREEP OF CONCRETE BEAM BRIDGE CONSIDERING PRESTRESS RELAXATION

文中以新建崇礼铁路重点控制工程赵川高架特大桥为研究对象,建立徐变识别系统,通过现场监测所得的应变数据与模拟结果计算桥梁混凝土的实际徐变值,在现有公路桥梁规范中的FIP-90模型的基础上,提出对现有徐变模型的系数修正,与传统徐变模型相比考虑了梁桥混凝土应变导致的预应力松弛,修正后的徐变模型与现场实测徐变值能较好吻合。利用MIDAS/Civil软件建立包含冬歇与施工间歇等时间因素的有限元模型,并导入修正后的徐变函数进行长期预测,以达到指导桥梁施工控制与预测桥梁服役期上拱的目的。

This paper takes the Zhaochuan Bridge,a key project of Chongli Railway,as the research object,established a creep identification system,and calculated the actual creep value of the bridge concrete based on the strain data and simulation results obtained from field monitoring.Based on the FIP-90 model in the existing highway bridge specification,the coefficient correction for the existing creep model was proposed.Compared with the traditional creep model,the prestress relaxation caused by the concrete strain of the beam bridge was considered.The modified creep model has a high consistency with the measured creep value.Use the MIDAS/Civil software to establish a finite element model including time factors such as winter break and construction break,and import the modified creep function for long-term prediction.It can realize the purpose of guiding bridge construction control and predicting arching during the service period of the bridge.