Experimental Study on Seismic Performance of Carbon Fibre Reinforced Plastics-Retrofitted Earthquake-Damaged Non-ductile Reinforced Concrete Frames
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摘要: 为了研究碳纤维增强复合材料(CFRP)加固震损非延性钢筋混凝土(RC)框架抗震性能,制作并完成了1榀1/2缩尺两层两跨非延性RC框架子结构试件加固前后的拟静力试验. 将试件加载至峰值承载力,对采用外包CFRP法对震损节点处进行加固后的试件进行试验研究,获得了CFRP加固震损非延性RC框架的破坏形态与滞回曲线,分析了其刚度、强度、延性和耗能等抗震性能指标,并与完好结构进行对比. 分析结果表明:CFRP加固对提高震损非延性钢筋混凝土框架结构的最大水平承载力、初始刚度有限,对其耗能能力提升明显;加固结构的平均位移延性系数为2.81;当其最大层间位移角到达1/50时,加固结构依然具有较大的安全储备空间,加固后的震损非延性RC框架结构可以用于地震区.
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关键词:
- 土木建筑结构 /
- 震损CFRP非延性钢筋混凝土框架 /
- 拟静力试验 /
- 抗震加固
Abstract: To investigate the seismic performance of earthquake-damaged non-ductile reinforced concrete (RC) frames retrofitted with carbon fiber reinforced polymer (CFRP), two pseudo-static tests were conducted on a 1/2 scale two-span and two-story specimen before and after its CFRP reinforcement. After the RC frame was loaded to its peak bearing capacity, specimens with seismic damaged parts strengthened with external CFRP textile were studied experimentally to obtain their failure modes and hysteretic curves. The seismic performance indexes of the CFRP-retrofitted frame, such as stiffness, strength, ductility and energy consumption, were analyzed and compared with the initial intact frame. The results show that the external CFRP reinforcement has no significant influence on the lateral strength and initial stiffness of the earthquake-damaged non-ductile RC frame, but the energy dissipation capacity of the retrofitted RC frame is obviously improved. The average displacement ductility factor of retrofitted RC frame is 2.81. When the maximum story drift ratio reaches 1/50, the retrofitted RC frame still has a large safety margin. The retrofitted earthquake-damage non-ductile RC frames can be used in seismic areas. -
表 1 各试件力学特征点
Table 1. Behavior of the specimens at different characteristic points
试件状态 方向 开裂点 屈服点 峰值点 极限点 Pcr/kN Δcr/mm Py/kN Δy/mm Pm/kN Δm/mm Pu/kN Δu/mm 未加固 正 — — 97.5 21.6 135.0 42.3 — — 反 −19.0 −2.7 −75.8 −19.8 −110.8 −49.4 — — 加固 正 — — 117.8 25.5 141.3 41.9 120.1 70.5 反 −56.7 −9.6 −93.5 −24.4 −113.6 −48.2 −96.7 −69.4 注:Pcr 和 Δcr 为开裂荷载和开裂荷载对应的位移;Py 和 Δy 为屈服荷载和屈服荷载对应的位移;Δm 为峰值荷载对应的位 移;Δu 为极限位移. 表 2 特征点刚度
Table 2. Measured stiffness at characteristic points
kN•mm−1 试件状态 方向 开裂点 屈服点 峰值点 极限点 未加固 正 — 4.50 3.19 — 负 7.01 3.83 2.24 — 加固 正 — 4.62 3.37 1.70 负 5.89 3.83 2.35 1.39 表 3 加固试件延性系数
Table 3. Ductility coefficients of CFRP-retrofitted earthquake-damaged specimen
方向 $\varDelta_{\mathrm{u} }$ $\varDelta_{\mathrm{y} }$ $ \mu $ $\bar \mu $ 正 70.51 25.49 2.77 2.81 负 −69.42 −24.41 2.84 表 4 延性系数最小值
Table 4. Minimum value of ductility coefficients
箍筋形式 一级 二级 三级 矩形普通箍筋 2.57 2.36 2.18 矩形复合箍筋 2.09 1.84 1.75 表 5 加固试件极限状态层间位移角
Table 5. Ultimate story drift ratio of CFRP-retrofitted earthquake-damaged specimen
位置 位移/mm 层间位移角 第 1 层 −38.68 1/38.78 第 2 层 30.88 1/48.58 表 6 加固试件特征点E及he
Table 6. E and he characteristic points of reinforced specimen
试件
状态屈服点 峰值点 极限点 E/
(kN•mm−1)he E/
(kN•mm−1)he E/
(kN•mm−1)he 未加固 730.2 0.050 2 525.0 0.070 — — 加固 1 297.6 0.080 3 940.5 0.100 6 509.5 0.136 比率 1.78 1.60 1.56 1.43 -
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