Abstract: Axial compression short colunm with round cross-section is reinforced by enlarging cross-section method, for it is short of bearing capacity. In order to study the destruction limits and the bearing capability of normal cross-section of rein- forced column, the radical stress of the reinforeed column is obtained through the iterative numerical solution, according to the force balance of concrete at the junction of old concrete and new concrete. The vertical compressive strength of old concrete is calculated by tri-axial stress ; the compressive strength of new concrete is calculated by pulling in ring and pressing in longitude. When pulling-strain of the new enclosed concrete reaches the strain limits, the new concrete rips; meanwhile, the strengthened column reaches the destruction limits.

Key words: enlarging cross-section method , strengthened column , secondary loading , tri-axial stress , numerical calculation ;

摘要： 轴心受压圆截面短柱因承载力不足而采用扩大截面法进行加固,为了研究加固柱的破坏界限和正截面承载 力,根据结合面处混凝土受力平衡,通过数值迭代解法求出加固柱的径向应变,从而按三向受压计算旧混凝土的纵 向抗压强度;新混凝土按环向受拉、纵向受压计算抗压强度。当外包新混凝土达到拉应变极限时,外包混凝土开 裂,加固柱达到破坏界限。

关键词: 扩大截面法, 加固柱, 二次受力, 三向受力, 数值计算