Buckling Strength of Steel Columns with Induced Deformation at Increasing High Temperature

通过试验和分析研究了连接钢梁热伸长引起的诱导接头平移角R对钢柱屈曲强度的影响，并对钢柱进行了两组屈曲试验（SN 490 B JIS等级），具有矩形横截面：（1）一种是在恒定高温下，另一种是在恒定轴向载荷下，在逐渐升高的温度下。第一个实验研究，使用恒定高温下的测试，结果表明，在室温下，诱导变形R使柱的最大轴向载荷Pmax降低15%，但在400℃以上，柱的破坏轴向载荷仅略低于未诱导变形时的轴向载荷。在轴向荷载作用下，通过温度升高的试验表明，当轴力比P/P_ =0.2 ~ 0.5时，由于诱导变形R，柱的破坏温度Tcr可降低10 ~ 50℃<yRT>。结果表明，只要采用适当的力学模型和高温下的钢材数据，数值分析可以准确地预测高温下有诱导变形的柱的屈曲特性。

An experimental and analytical study was conducted to evaluate the effects of induced joint translation angle R caused by the thermal elongation of connected heated steel beams on the buckling strength of steel columns.Two sets of buckling tests were performed using steel columns (SN490B JIS grade) with a rectangular cross-section: (1) one at a constant high temperature and (2) the other at increasingly higher temperatures under a constant axial load.The first experimental study, using tests at a constant high temperature, indicated that the reduction of the maximum axial load Pmax due to induced deformation R can be up to 15% at room temperature, but, at above 400℃, the column failure axial load is only slightly lower man that without inducing the deformation.The second experimental study, using tests at increasingly higher temperatures under a constant axial load, indicated that the reduction in the column failure temperature Tcr due to induced deformation R can be from 10℃ to 50℃, depending on the axial force ratio from P/P_<yRT>=0.2 to 0.5.The results of these tests were simulated by a one-dimensional finite-element procedure developed by the author, and it was shown that numerical analysis can be used to provide accurate predictions of the buckling characteristics of columns with an induced deformation at high temperatures when an appropriate mechanical model and data of steel materials at high temperature are used.