锚固的双向纤维布约束加固钢筋混凝土柱抗震性能

Seismic behaviors of reinforced concrete column confined by bidirectional fiber reinforced polymer composite with anchor

  • 摘要: 双向纤维增强聚合物(Fiber reinforced polymer,FRP)复合材料布具有良好的两向正交抗拉性能,与传统单向布相比,使用其约束加固柱时能使构件获得抗剪、抗弯承载力和抗震延性的同时提高。开展了基于纤维锚钉锚固的双向布约束加固钢筋混凝土柱低周反复加载试验,参数包含布种类、层数和锚固方式,研究了加固柱的破坏模式、抗震性能和材料应变。 结果表明,柱在约束加固前后的破坏形态由剪切转变为弯曲破坏,构件延性大幅度提高;同层数的双向纤维布在环向应变值发挥少于单向布;使用锚钉可显著提升双向布纵向纤维应变,其应变值比未锚固前的提高了约1.5倍;并进一步提高约束柱抗弯承载力,较未加锚固前的约束柱承载力提高了2.9%~7.1%。成果可为双向纤维布在既有结构加固领域的应用提供指导。

     

    Abstract: The bidirectional fibers reinforced polymers (FRP) sheets have good tensile properties in two orthogonal direction. Compared with using traditional unidirectional fabrics, the seismic ductility, shear and flexural capacities of strengthened columns confined by bidirectional FRP sheets are simultaneously improved. Based on using bidirectional FRP sheets with fiber anchors, six reinforced concrete columns were tested under low cyclic lateral loading. The experimental parameters included FRP types, layer number and anchorage schemes, which were intended to study the failure mode, seismic performance and material strain of different confined columns. The test results show that the failure mode of the columns changes from shear to bending failure after confinement, and the hoop working strain of bidirectional FRP sheets is less than that of unidirectional FRP sheets under the same layers. The effective strain of longitudinal fibers in bidirectional FRP sheets significantly increases when using FRP anchor, the fiber strain value is about 1.5 times higher than that before the anchorage, which further improves the flexural capacity of confined columns, the bearing capacities of the confined columns increase by 2.9%-7.1% than that before the anchorage. The research results provide guidance for the application of bidirectional FRP sheets in strengthening existing reinforced concrete structure.

     

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