钢管混凝土轴心受压构件的徐变预测模型及其徐变性能分析

发布时间：2018-05-12 19:21

本文选题：钢管混凝土 + 轴心受压　；参考：《工程力学》2017年06期

【摘要】：为研究混凝土徐变对钢管混凝土轴心受压构件长期受力性能的影响,考虑构件截面内力重分布,建立了钢管混凝土轴心受压构件截面应力和应变以徐变系数为参数的随混凝土龄期变化关系的理论模型,结合已有试验数据和国内外常用12种混凝土徐变预测模型对该模型进行验证,并找到了适用于钢管混凝土轴心受压构件的徐变预测模型——Huo模型;在此基础上,计算并分析了钢管混凝土轴心受压构件混凝土龄期为10000 d的截面应力和应变;通过对混凝土强度等级、环境年平均相对湿度、初始加载龄期、含钢率、构件长度、截面应力水平等因素的不同取值,分析了各因素对钢管混凝土轴心受压构件徐变性能的影响程度及规律。结果表明:当钢管混凝土轴心受压构件的轴力不大于其极限承载力的60%时,随着加载龄期的增长,钢管截面应力逐渐增大,最大变化量达61.4%,而混凝土截面应力逐渐减小,最大变化量达26.2%;加载初期构件应变增长迅速,1000 d以后应变增长速度减慢,构件最终应变是初始应变的1.61倍;在轴压比相同的条件下,钢管混凝土轴心受压构件的徐变应变终值随着混凝土强度等级的提高而逐渐增大,随着含钢率的增大显著减小,随着初始加载龄期、环境年平均相对湿度、构件长度的增大而逐渐减小,轴压比不大于0.6时,其徐变应变终值随轴压比增长。研究成果可为钢管混凝土轴心受压构件在正常使用阶段徐变计算以及徐变变形控制提供依据。
[Abstract]:In order to study the effect of concrete creep on the long-term behavior of concrete filled steel tube (CFST) members subjected to axial compression, the redistribution of internal forces in the section of the members is considered. A theoretical model of stress and strain of concrete filled steel tube (CFST) members subjected to axial compression with creep coefficient as a parameter is established. Based on the experimental data and 12 kinds of concrete creep prediction models commonly used at home and abroad, this model is verified, and the Huo model, which is suitable for concrete filled steel tube members under axial compression, is found. The section stress and strain of concrete-filled steel tubular (CFST) members with an age of 10000 d are calculated and analyzed, and the concrete strength grade, environmental average relative humidity, initial loading age, steel content and member length are calculated and analyzed. The influence of different factors on the creep behavior of concrete-filled steel tubular (CFST) members under axial compression is analyzed. The results show that when the axial force of concrete-filled steel tubular (CFST) members under axial compression is less than 60% of their ultimate bearing capacity, with the increase of loading age, the stress of steel tube section increases gradually, and the maximum variation reaches 61.4, while the stress of concrete section decreases gradually. The maximum variation is 26.20.In the initial loading stage, the strain growth rate slows down after 1000 d, and the final strain is 1.61 times of the initial strain. Under the same axial compression ratio, the strain growth rate of the component is 1.61 times that of the initial strain. The ultimate creep strain value of concrete-filled steel tubular (CFST) members under axial compression increases gradually with the increase of concrete strength grade, decreases significantly with the increase of steel content, and with the initial loading age, the average annual relative humidity of the environment increases. When the axial compression ratio is less than 0.6, the ultimate creep strain value increases with the axial compression ratio. The results can provide basis for creep calculation and creep deformation control of concrete-filled steel tubular (CFST) members under axial compression.
【作者单位】：中国农业大学水利与土木工程学院;
【基金】：北京市自然科学基金项目(3144029) 国家自然科学基金项目(51279206) 农业部农业设施结构工程重点实验室开放课题项目(201502) 中央高校基本科研业务费专项资金项目(2015SY004)
【分类号】：TU398.9

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