高强不锈钢绞线网增强ECC加固RC短柱轴心受压试验

Compressive behavior of RC short columns strengthened with high-strength stainless steel wire strand mesh and ECC

  • 摘要: 在新型复合材料“高强不锈钢绞线网增强工程水泥基复合材料(ECC) (简称HSME)”的力学性能和约束素混凝土受压性能研究基础上,将钢筋混凝土(RC)短柱配筋率和混凝土强度以及加固层的ECC强度和横向钢绞线配筋率作为参数,试验研究高强不锈钢绞线网增强ECC加固RC短柱轴心受压性能。结果表明,和未加固RC短柱相比,HSME加固RC短柱不仅承载力大幅度提升,而且破坏时裂而不碎、具有明显的延性破坏特征,开裂荷载、峰值荷载及峰值位移显著提高;荷载达峰值荷载80%左右和峰值荷载时,试件表面最大裂缝宽度仅为0.09 mm和0.25 mm,表现出优良的多缝开裂和裂缝控制能力。HSME加固RC短柱荷载-位移曲线属于偏态的单峰曲线,包含弹性、裂缝发展、最大荷载和承载力下降四个阶段。随着ECC抗压强度和横向不锈钢绞线配筋率增大,HSME加固柱开裂荷载和峰值荷载均明显增大;增大RC柱配筋率和混凝土强度可提高加固柱峰值荷载和延性。

     

    Abstract: Based on the research of the mechanical property of the new composite material “high strength stainless steel wire mesh reinforced engineered cementitious composite (ECC) (referred to as HSME)” and compression performance of confined concrete with this material, the compressive behavior of reinforced concrete (RC) short columns strengthened with high strength stainless steel wire mesh reinforced ECC was studied. The test parameters contained the reinforcement ratio and concrete strength of RC short columns, the ECC strength of reinforcement layer and the reinforcement ratio of transverse steel strands. The results indicate that, compared with the unstrengthened RC short columns, the specimens of HSME-strengthened RC short columns not only greatly increase the bearing capacity, but also crack without breaking when they are damaged, exhibiting obvious ductile failure pattern. Meanwhile, the cracking load, peak load and peak displacement are significantly increased. When the applied load reaches about 80% of the peak load and peak load, the maximum crack widths on the surface of the specimen are only 0.09 mm and 0.25 mm, respectively, showing excellent multi-slit cracking ability and crack control capabilities. The load-displacement curve of the HSME-strengthened RC short column is drawn as a skewed single-peak curve, which includes four stages: Elasticity, crack development, maximum load and bearing capacity decline. With the increasing of ECC compressive strength and transverse stainless steel strands reinforcement ratio, the cracking load and peak load of HSME strengthened columns increase significantly. Increasing the reinforcement ratio and concrete strength of the RC column could increase the peak load and the ductility of the HSME strengthened column.

     

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