长期荷载下核心柱的变形和应力重分布

Abstract

基于ACI 209的混凝土收缩和徐变模型,采用龄期调整有效模量法,进行核心柱(即在普通的钢筋混凝土柱截面的核心增设一钢管的柱)受压构件在长期轴向荷载作用下的变形以及应力重分布的分析和计算,并考察加荷龄期、持荷大小、截面含钢率等参数的影响。分析表明:徐变和收缩引起的变形在持荷的早期阶段(加载后的4、5个月内)发展较为迅速,应力重分布的结果将导致柱中钢管应力显著增加。

Based on the ACI 209 method for predicting the creep and shrinkage of concrete,a study was conducted using age-adjusted effective modulus method to evaluate the deformation and stress redistribution of the long-term axially loaded concrete columns reinforced with concrete filled steel tube(CCRST),which was an ordinary reinforced-concrete column where there was a steel tube designed to be put in the core additionally.In addition,it was also examined the influence of different parameters,such as the age at first loading,the magnitude of loading and the area ratio of steel to gross section on the deformation and stress redistribution of the axially loaded CCRST columns.The analysis indicates that the deformation caused by the creep and shrinkage develops quickly in the early loading phase(within 4 or 5 months after loading),and the results of the stress redistribution will lead to a remarkable increase of the stress in steel tube.