外包配筋ECC组合柱抗震性能试验研究与有限元分析

工程用水泥基复合材料(ECC)是一种具有高延性、高韧性和多缝开裂特征的纤维增强水泥基复合材料，采用配筋ECC制作柱永久性模板，其内浇筑素混凝土形成组合柱。设计了4根外包配筋ECC组合柱和1根钢筋混凝土(RC)对比柱，开展拟静力试验，研究组合柱破坏形态和抗震性能。试验结果表明：ECC组合柱表现出明显的多缝开裂特征和更好的延性；随着剪跨比增加，柱端水平荷载-位移滞回曲线饱满，峰值荷载降低，但位移延性系数和能量耗散系数分别提高50%和185%；配箍率较高的构件，柱端水平荷载-位移滞回曲线较饱满，刚度退化较缓，变形能力较大。基于OpenSees平台，嵌入ECC材料本构模型，模拟了试验柱端水平荷载-位移曲线，并与试验结果进行对比，验证了有限元模型的准确性。

Experimental study and finite element analysis of seismic behavior of reinforced ECC composite columns

Engineered cementitious composites (ECC) is a high toughness composite material with pseudo strain hardening behavior and multiple cracking characteristics. ECC permanent formwork for the construction of durable concrete column forming reinforced ECC composite column was proposed. Quasi-static tests on four reinforced ECC composite column and one reinforced concrete (RC) column were carried out, and the failure pattern and seismic behavior were investigated. Experimental results indicate that reinforced ECC composite columns show better seismic performance in terms of ductility, energy dissipation capacity, and damage tolerance, compared with RC columns. Increasing in shear span-to-depth ratio can result in increase of displacement ductility factor (enhanced by 50%) and energy dissipation capacity (enhanced by 185%), however, the load-carrying capacity becomes lower. In addition, with the increase of stirrup ratio, the deformation capacity increases and the stiffness degradation becomes lower. Proposed constitutive model of reinforced ECC was coded into the OpenSees platform and applied to simulate the behavior of specimens. The simulation results indicate that the proposed constitutive model is reasonably accurate in simulating the mechanical properties of reinforced ECC composite columns.