圆钢管高强再生混凝土柱重复加载偏压试验

Experimental study on high strength recycled concrete-filled circular steel tube columns under repeated eccentric loading

为研究圆钢管高强再生混凝土柱偏心受压性能,完成了4个试件的单调重复加载试验.4个试件分为两组,第一组试件包括圆钢管普通混凝土柱和圆钢管再生混凝土柱,偏心距100 mm;第二组试件与第一组试件相同,区别在于偏心距为160 mm.通过试验,得到了荷载-位移曲线、荷载-应变曲线、应变沿截面高度分布情况,分析了各试件的破坏特征、承载力、刚度、延性和耗能等.利用国内外相关规程对圆钢管再生混凝土偏心受压柱进行承载力计算,并与试验结果比对.研究表明:圆钢管高强再生混凝土偏心受压柱的损伤破坏过程与普通混凝土柱相似,承载能力和变形性能较普通混凝土试件有所提高;截面应变分布与平截面假定符合较好;随着偏心距增大,试件承载力降低,刚度退化加剧,变形能力增强.

The eccentric compression performance of concrete filled circular steel tubular （ CFCST） columns using high-strength recycled aggregate concrete （ RAC） instead of normal concrete （ NC） was studied through repeat load tests on four specimens in this paper. Four specimens were divided into two groups; the first set of two specimens included a CFCST column filled with RAC and a normal CFCST column, the eccentricity was 100 mm. The second group had the same specimens and the difference was that the eccentricity was 160 mm. Load-deformation and stress-strain curves as well as the strain distribution over the cross section were obtained through the experiment. The failure characteristic, load-bearing capacity, stiffness, ductility, energy dissipation and residual deformation of the specimens were analyzed. The obtained results are compared with the ultimate strengths of CFCST columns predicted by existing design codes. The test results indicate that damage development and failure mode of CFCST columns with RAC are similar to those of normal CFCST columns. The replacement of NC with RAC has beneficial effects on the load-carrying capacity and deformation properties. The strain distribution was found to accord well with the plane section assumption. With the incensement of eccentricity, the load-carrying capacity decreased, the stiffness degradation intensified, and the deformation ability improved.