外套钢管加固有初始力钢筋混凝土短柱结构承载力计算方法研究

Study on Computational Method of Bearing Capacity of RC Short Columns with Initial Stress Strengthened by External Steel Tube

为了计算外套钢管加固既有钢筋混凝土墩柱的轴压承载力,以圆形墩柱在加固前承担较低初始力的加固结构(情况1)为研究对象,采用极限平衡法计算加固结构钢管对原柱混凝土和填充混凝土套箍指标的临界分界值。采用插值的方式改进了两种韩林海钢管混凝土应力-应变曲线,使之适合二次受力加固结构混凝土的应力应变特点,探讨了混凝土徐变对加固结构的承载力的影响,在此基础上使用静力法推导出外套钢管加固短柱桥墩结构的轴压承载力的计算公式,其承载力计算结果与试验数据结果相对比。结果表明:两者符合较好,同时与其他学者的研究数据对比,亦符合较好。

To calculate the axial bearing capacity of existing RC column coated with steel tube,taking the circular column with a relative low initial stress（ case 1） before strengthening as research object,the critical boundary value of reinforcing steel tube against the original and filled concretes is calculated by the limit equilibrium method. The 2 kinds of steel tubular concrete stress-strain curves initially proposed by Han Linhai are improved by interpolation method to match the characteristic of concrete structure subjected to secondary loading,and the influence of concrete creep on the bearing capacity of the reinforced structures is discussed. On this basis,the formula of axial bearing capacity for short column pier structure strengthened by coated steel tube is derived by using static method. Comparing the computational result with the correspondent experimental data,it shows that both of them are in good agreement and they are consistent with the data from other researchers.