大跨径钢混组合梁桥徐变效应研究

Study on Creep Effect of Long-span Steel Concrete Combined Beam Bridge

利用大型有限元软件Midas建立港珠澳钢混组合梁桥精细化有限元模型。根据港珠澳大桥所处地理位置和气候特点,对传统的《公路钢筋混凝土及预应力混凝土桥涵设计规范》(JTG D62-2004)的徐变预测模型进行修正,建立考虑变温影响的徐变修正模型,计算得到徐变效应产生的桥梁长期挠度值以及应力变化关系。通过分析在不同初始加载时间下桥梁边跨跨中挠度最大值增长情况,总结得到了徐变在全年的发展规律。结果表明,使用该修正模型计算组合梁桥徐变效应能够适应当地季节更替明显、温度变化大的特点,能够更为精确地计算徐变效应引起的长期挠度值,为桥梁设计施工提供科学依据。

The large finite element software Midas is used to establish a refined finite element model of Hongkong-Zhuhai-Macao Steel Concrete Combined Beam Bridge. Based on the geographical position and climate characteristics of the bridge, the traditional creep forecast model of Highway Steel Reinforced Concrete and Pre-stressed Concrete Bridge Culvert Design Standard(JTG D62-2004) is revised, the creep revising model considering the effect of changing temperature is established, and the calculation gives the long-term deflection value and the stress changing relationship of bridge produced by creep effect. The article analyzes the maximum value increment of mid-span deflection in side span of bridge in the different initial loading stages, and sums up the development law of creep in the whole year. The result shows that the use of this revising model to calculate the creep effect of combined beam bridge can suit the local characteristics of obvious seasonal replacement and large temperature changing, and can more accurately calculate the long-term deflection value caused by creep, which can be referred for the design and construction of the similarbridges.