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

为了研究受热钢梁热伸长诱导节点平移角R对钢柱屈曲强度的影响，对SN490BJIS级矩形截面钢柱进行了两组屈曲试验：(1)恒定高温和(2)恒定轴向荷载作用下的高温屈曲试验。第一组试验表明，在常温下，诱导变形R可使最大轴向荷载Pmax降低15%，但在400℃以上时，最大轴向荷载Pmax可降低15%。第二个试验研究表明，在恒定轴力作用下，随着温度的升高，柱的破坏温度Tcr可降低10℃到50℃，这取决于P/P&lt的轴力比；用作者开发的一维有限元程序对试验结果进行了模拟，结果表明，如果采用合适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.