摘要
为解决由于没有实测数据作参考而造成对徐变预测不准确的问题,选取已建的3座高铁特大跨混凝土连续梁,对其收缩、徐变的设计、计算、实测及远期预测进行研究。通过分析比较现有的3种徐变计算方法,最终选取采用《铁路桥涵钢筋混凝土和预应力混凝土设计规范》的方法计算徐变,对比计算与实测结果,分析表明:混凝土徐变变形一年内可完成总量的70%以上;梁合龙后,二期恒载加载龄期在60 d时徐变速率对梁挠度的后期影响非常小;为控制徐变,设计梁时应使截面上、下缘应力在预应力及恒载作用下尽量接近;采用所选规范计算收缩、徐变可满足工程要求;根据实测变形数据,采用双曲线法预测的连续梁长期徐变与数值计算基本吻合。
To resolve the problem of inaccurate creep prediction due to the voidance of reference of actually measured data, the long span concrete continuous beams of three completed bridges on high-speed railway are selected and the shrinkage, creep design, calculation, measure- ments and long-term prediction of the beams are studied. Through analysis and comparison of the existing three kinds of the creep calculation methods, the method in the Code for Design on Reinforced and Prestressed Concrete Structure of Railway Bridge and Culvert is chosen to calculate the creep and the calculation of the creep is compared to the measurements. The results of the analysis indicate that more than 70%of the total creep deformation of the concrete can be completed within one year. After closure of the beams, the influence of the creep rate at the time of 60 d age of concrete after imposing the second phase dead load on the late period deflection of the beams is very little. However, to control the creep, when a beam is designed, the stress in the upper and lower flanges of the section of the beam under the action of prestressing and dead load should be kept possibly identical. The calculation of the shrinkage and creep by the chosen code can meet the requirements for construction and in accordance with the measured data of the deformation, the prediction of long-term creep of the concrete continuous beams by the hyperbolic method is basically agreeable with that by the numerical calculation.
出处
《桥梁建设》
EI
CSCD
北大核心
2010年第4期23-26,共4页
Bridge Construction
关键词
高速铁路
无碴轨道
连续梁
徐变
预测
应用
high-speed railway
ballastless track
continuous beam
creep
prediction
appli-cation.
