预应力轴压撑杆钢柱高温性能试验研究与数值分析

发布时间：2018-11-07 10:18

【摘要】：为研究预应力轴压撑杆钢柱的高温性能,进行了2根预应力撑杆钢柱高温试验。试验结果表明:拉索无防火措施时,其相对张力在初始升温阶段就迅速下降,直至完全松弛;预应力撑杆钢柱的轴向变形先由于热膨胀效应轴向伸长,而后在压力作用下轴向压缩;临界状态时,撑杆柱出现对称和反对称两种失稳形态。采用验证后的ANSYS有限元分析模型,考虑材料非线性、几何非线性和初始缺陷等,分析了荷载比、相对轴向刚度比和预应力比等3个关键参数对预应力撑杆柱高温性能的影响,得到了一系列拉索相对张力、侧向变形和轴向变形分别与时间的关系曲线。分析表明:预应力撑杆柱中拉索张力很快在高温下逐渐松弛,达到张力松弛所需时间主要受预应力比影响;预应力撑杆钢柱的侧向变形在升温初期缓慢增长,在失效前增长迅速;随着荷载比增大,预应力撑杆柱侧向变形和轴向变形越来越明显,且达到峰值所需时间不断缩短;预应力比对撑杆钢柱失效临界温度影响较小,但对预应力撑杆柱的破坏形态有较大影响。
[Abstract]:In order to study the high temperature performance of prestressed steel columns under axial compression, two prestressed steel columns were tested at high temperature. The experimental results show that the relative tension decreases rapidly at the initial heating stage until complete relaxation. The axial deformation of prestressed steel columns is firstly due to the thermal expansion effect, and then under axial compression under the action of pressure, and at critical state, there are two kinds of instability patterns: symmetrical and antisymmetric. By using the verified ANSYS finite element analysis model, considering material nonlinearity, geometric nonlinearity and initial defects, the effects of three key parameters, such as load ratio, relative axial stiffness ratio and prestress ratio, on the high temperature performance of prestressed braced columns are analyzed. A series of relative tension, lateral deformation and axial deformation curves are obtained. The analysis shows that the tension of the cable in the prestressed braced column is loosening rapidly at high temperature, and the time required to achieve the tension relaxation is mainly affected by the prestress ratio. The lateral deformation of prestressed steel column increases slowly at the initial stage of heating up, and increases rapidly before failure, and with the increase of load ratio, the lateral and axial deformation of prestressed steel column becomes more and more obvious, and the time required to reach the peak value is shortened. The influence of prestress ratio on failure critical temperature of braced steel column is small, but it has great influence on failure pattern of prestressed steel column.
【作者单位】：武汉理工大学土木工程与建筑学院;武汉地铁集团有限公司;广州杰赛科技股份有限公司;同济大学土木工程防灾国家重点实验室;
【基金】：国家自然科学基金项目(51278394)
【分类号】：TU391

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