潮汐区GFRP筋珊瑚海洋混凝土柱轴压性能试验及承载力计算

Test on axial compression performance and bearing capacity calculation of GFRP bars reinforced coral aggregate marine concrete columns exposed to tidal area

  • 摘要: 为解决海洋工程中钢筋耐久性不足以及海上建筑材料短缺问题,提出了一种新型玻璃纤维增强树脂复合材料(GFRP)筋珊瑚海洋混凝土柱。对28个海洋潮汐区混凝土柱试件进行轴压静力加载试验,观察了受力破坏过程,获取了荷载-位移全过程曲线和特征点应力应变数据,分析了试件的受压破损机制及各参数对轴压力学性能的影响规律,并探讨了潮汐区该类新型构件的承载力计算方法。结果表明:GFRP筋珊瑚海洋混凝土柱的轴压破坏表现为表面裂缝宽而疏,粗骨料断裂,保护层混凝土被分割成条带状;与配钢筋试件相比,GFRP筋试件的承载力降低了38%,特征点应变也更小;在GFRP筋试件中,增大纵筋或螺旋箍筋配筋率并不能显著提高其承载能力,但可提高其变形性能;在270天范围内的短期潮汐环境下,试件的承载力先降低后升高,轴压延性呈波动变化趋势且变化幅值为25%。最后,拟合并引入材料性能变化参数得出潮汐区GFRP筋珊瑚海洋混凝土柱承载力计算公式。

     

    Abstract: In order to solve insufficient durability of steel bars and shortage of offshore construction materials, a new type of glass fiber reinforced polymer (GFRP) bars reinforced coral aggregate marine concrete column was proposed. 28 columns in marine tidal area were tested under axial compression. Firstly, the failure process of the specimens was observed, the load-displacement curves and the stress-strain data were obtained. Then, the failure mechanism of the specimens and the influence of various parameters on the mechanical properties were analyzed. At last, the bearing capacity calculation of this new type of member in the tidal area was discussed. The results show that the failure modes of GFRP bars reinforced coral aggregate marine concrete columns include wide and sparse cracks on the surface, coarse aggregate fracture and cover concrete divided into strips. Compared with the reinforced concrete (RC) specimen, the bearing capacity of GFRP bars reinforced coral aggregate marine concrete specimen decreases by 38%, and the strain of characteristic points is smaller. For GFRP specimens, increasing the reinforcement ratio of longitudinal bars or spiral stirrups can’t effectively improve the bearing capacity of specimens, but can improve their deformation performance. In the short-term tidal environment within 270 days, the bearing capacity of specimens first decreases and then increases, and the ductility shows a fluctuating trend with a variation amplitude of 25%. Finally, the calculation formulas for calculating the bearing capacity of the GFRP bars reinforced coral aggregate marine concrete columns in the tidal area were proposed by fitting and introducing variation parameters of material property.

     

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