混凝土早龄期拉伸徐变的预测与仿真  

Prediction and simulation of concrete tensile creep at early ages

作　　者：郭磊[1,2] 陈守开[1,2] 白卫峰[1,2] 郭利霞[1,2] 

机构地区：[1]华北水利水电大学,河南郑州450045 [2]水资源高效利用与保障工程河南省协同创新中心,河南郑州450045

出　　处：《混凝土》2016年第5期26-30,34,共6页Concrete

基　　金：国家自然科学基金资助项目(51109081;51309101);水利部公益性行业科研专项经费项目(201301025)

摘　　要：针对目前混凝土结构温控仿真及评价中存在缺乏考虑早龄期拉伸徐变的问题,建立了考虑多因素影响的拉伸徐变系数预测通式,开发了考虑拉伸徐变效应的混凝土温控仿真程序。利用拉伸徐变试验成果,对代表性的徐变系数预测模型,即CEBFIP90模型、ACI模型及双幂模型进行了参数识别、规律分析及模型修正后,用于混凝土早龄期拉伸徐变的预测与仿真。通过有限元算例,分析拉伸徐变对早龄期混凝土表面应力场的影响,结果表明拉伸徐变能有效减小早龄期混凝土表面拉应力值和改善表面应力场分布,对温控防裂有利。Aiming at the problem of no tensile creep in simulation and evaluation of temperature control of concrete structure, the basic function of tensile creep coefficient was built by means of trend analysis of concrete creep.Based on tensile creep end restraint experi- ment of a ratio concrete, the creep coefficient classical prediction model, namely CEB - FIP90 model, ACI model and the double expo- nential model was fitted, and the regularity was analyzed, and then the double exponential model was modified to improve its fitting effect.The results show that after proper correction, compression creep model can be used to predict concrete tensile creep at early age. Using temperature control program with tensile creep and FEM case, the effect of tensile creep in surface stress field is analyzed at early age. The result has been proved that concrete tensile creep can reduce the surface tension value and improve the surface stress distribu- tion, which is favorable for temperature control and crack prevention.

关 键 词：混凝土 拉伸徐变 预测模型 早龄期 仿真 拉应力 

分 类 号：TU528.01[建筑科学—建筑技术科学]