反复荷载下型钢混凝土柱粘结滑移性能试验研究

EXPERIMENTAL STUDY ON BOND SLIP BEHAVIOR BETWEEN SHAPE STEEL AND CONCRETE IN SRC COLUMNS UNDER CYCLIC REVERSED LOADING

通过在型钢翼缘外侧布置电阻应变片和滑移传感器,对轴力和反复水平荷载作用下型钢混凝土柱的粘结滑移性能进行了试验研究。由试验得到了水平荷载-滑移滞回曲线和骨架曲线、粘结应力和滑移沿柱高的分布规律;分析了荷载循环次数对粘结应力和滑移量的影响,提出了粘结应力退化率的计算公式。试验结果表明,型钢混凝土的荷载-滑移滞回曲线比较丰满,在整个加载过程中没有明显的"捏拢"现象。水平荷载的上升阶段,粘结应力的最大值位于柱的中部,由中部向两端递减,沿柱高呈典型的抛物线状分布;最大荷载后的荷载下降阶段,粘结应力的最大值向柱顶偏移,柱根处由于型钢翼缘的屈服,粘结应力减小为零,沿柱高出现一定范围的"无粘结区"。在整个加载过程中,柱根处的滑移量最大,由柱根向柱顶逐渐递减,沿柱高大致呈指数分布。随着荷载循环次数的增加,粘结应力不断减小,滑移量不断增大,出现明显的粘结退化现象。

This paper studies bond slip behavior of steel reinforced concrete （SRC） columns under constant axial load and cyclic reversed horizontal load. With strain gauges and slip transfers embedded on flanges of the shape steels, the test generates hysteretic and skeleton curves of slip against horizontal load. The distribution of bond stress and slip along columns are also obtained. Influence of load cycle number on bond stresses and slips are analyzed, and calculating formula for bond degeneration is presented. Test results show that the hysteretic curve of slip against horizontal load is chubbiness without pinching. At the stage before ultimate horizontal load, bond stress is distributed in parabola along columns. At load-descending stage, the maximum bond stress occurs at the top of columns, and bond stress at the bottom of columns decreases to zero due to the yielding of steel flanges, leading to the occurrence of zero-bone zone along columns. In the whole stage of loading, the interior slip between shape steel and concrete is exponentially distributed along columns. With the increase of load cycle number, bond stresses along columns gradually decrease, but slips gradually increase, demonstrating bond degeneration.