再生混凝土短柱抗震性能试验研究

An Experimental Study on the Seismic Behavior of Recycled Concrete Short Columns with Crossed Reinforcing Bars

本文进行了4个剪跨比为1.75的再生混凝土短柱模型抗震性能对比试验,模型按1/2缩尺。模型1为普通混凝土短柱,模型2为再生粗细骨料取代率均为50%的再生混凝土短柱,模型3为再生粗细骨料取代率均为100%的再生混凝土短柱,模型4为再生粗细骨料取代率均为100%且带交叉钢筋的再生混凝土短柱。分析了各模型的承载力、刚度及其退化过程、滞回特性、位移延性、耗能能力、破坏形态。研究表明:随着再生骨料取代率的增加,其混凝土的弹性模量明显减小,试件初始刚度、承载力、耗能能力明显下降;加设交叉钢筋的试件抗震性能显著提高;再生混凝土柱可以在轴压比较小的结构中应用。提出了基于再生混凝土强度折减的承载力简化计算方法,计算结果与实测值符合较好。

A comparative study is conducted on the seismic behaviors of four 1 / 2 scale RC short column models with 1.75 shear span ratios. The first model is natural concrete short column, the second is short column with 50% replacement of recycled aggregate, the third is short column with 100% replacement of recycled aggregate, and the forth is recycled concrete short column with concealed bracings. The stiffness and its degradation, load-carrying capacity, ductility, hysteretic behavior, energy dissipation and failure phenomena of each short column were analyzed. Our results show that, with the increase of replacement ratio of recycled aggregate, the elastic modulus of concrete, the initial stiffness, the load-carrying capacities, and the energy dissipation values of the specimens significantly decreased. We also found that seismic behavior may be improved by adding crossed reinforcing bars in short column, and recycled concrete can be used for multilayer seismic structure columns with low axial compression ratio. Finally, we propose a calculation method based on bearing capacity of strength-reduction, from which the calculating results are in good agreement with the experimental observation.