配筋钢管混凝土柱抗火性能试验研究

Test research on fire resistance performance of bar-reinforced concrete filled steel tubular columns

为了提高钢管混凝土柱的抗火性能,在钢管混凝土柱中配置纵向钢筋和箍筋.对3根配筋钢管混凝土柱和1根钢管混凝土柱在恒定轴压荷载、两端简支条件下进行了火灾行为的试验研究.研究了配筋钢管混凝土柱的火灾反应、变形和破坏过程,测量了钢管混凝土柱截面温度场,并分析了钢管和配筋对钢管混凝土柱抗火性能的影响.试验表明,试验柱的破坏形态都是弯曲型,高温下配筋钢管混凝土的钢管退出工作后,由内部的钢筋混凝土圆柱承受荷载,其耐火极限比不配筋的钢管混凝土柱大得多,并且纵向钢筋数量多的配筋钢管混凝土柱,其耐火极限比配筋少的要大.对试验结果分析表明,耐火极限的计算值和试验值符合较好.

In order to improve the fire resistance performance,the longitudinal reinforcing bars and stirrups are placed inside the concrete filled steel tubular columns.A test research is performed for three bar-reinforced concrete filled steel tubular columns and one steel tubular column,which are all simple supported on both ends and under the constant axial pressure load.The responses,deformation and failure process of the bar-reinforced concrete filled steel tubular columns under fire are investigated.The sectional temperature field is measured,and the effects of the steel tube and reinforcing bars on the fire resistance performance are analyzed.The test results show that the failure modes of the tested columns are all bending modes.After the steel tubes of bar-reinforced concrete filled steel tubular columns stop working under high temperature,the loads are born by the inside circular reinforced concrete column.Therefore,its ultimate fire resistance value is much greater than that of the steel tubular column.Besides,the ultimate fire resistance value of bar-reinforced concrete filled steel tubular columns with more longitudinal bars is greater than that of columns with less reinforcing bars.The analysis results show that the calculation results of the ultimate fire resistance value agree well with the testing results.