CFRP加固锈蚀钢筋混凝土短柱的抗震性能

为评估CFRP加固锈蚀钢筋混凝土短柱抗震性能的效果,选取1根未锈蚀钢筋混凝土短柱、2根锈蚀钢筋混凝土短柱和4根CFRP加固锈蚀钢筋混凝土短柱进行抗震性能试验研究,考察了CFRP加固量、细骨料类型对抗震加固效果的影响情况,建议了CFRP加固锈蚀钢筋混凝土短柱受剪承载力的实用计算公式。结果表明:钢筋锈蚀会降低短柱的抗震性能,锈蚀钢筋试件的受剪承载力、极限变形能力和累积滞回耗能较未锈蚀钢筋试件分别降低了7.8%、35.5%和42.2%;外包CFRP加固能将锈蚀钢筋试件的受剪承载力提高至未锈蚀钢筋试件的107.1%～109.1%,并显著改善短柱的延性和耗能能力;外包CFRP的层数由1层增至2层时,加固试件的受剪承载力提高较少,且试件达到峰值荷载时,CFRP的最大应变减少;在钢筋锈蚀前后和CFRP加固前后,混凝土短柱无量纲近极限滞回环的滞回规则大体相同。

Seismic performance of corroded reinforced concrete short columns strengthened with CFRP

To investigate the influence of CFRP and fine aggregate type on strengthened seismic performance of corroded reinforced concrete short columns(RCSCs), the pseudo-static tests of one un-corroded reinforced concrete short column reinforceel concrete short column(RCSC), two corroded RCSCs and four corroded RCSCs strengthened with CFRP were carried out in this study. Besides, a practical method to calculate the shear strength of corroded reinforced concrete columns strengthened with CFRP was suggested. Experimental results show that the corrosion of steel bars will weaken the seismic performance of short columns. The shear bearing capacity, ultimate deformation capacity and cumulative hysteretic energy dissipation of corroded RCSCs are reduced by 7.8%, 35.5% and 42.2%, respectively. CFRP wrapping can enhance the shear strength of corroded RCSCs to a level of 107.1%~109.1% of that un-corroded RCSC, and can significantly improve the ductility and energy dissipation capacity of corroded RCSCs. When CFRP layer is increased from one to two, the shear capacity of the reinforced specimen is marginally improved, and the maximum strain of CFRP decreases when the specimen reaches the peak load. Moreover, the hysteretic rules for the dimensionless hysteresis loops of RCSCs closed to limit state for cases with un-corrosion and with corrosion, without CFRP strengthening and with CFRP strengthening are similar.