盐雾干湿循环对预应力CFRP加固梁抗弯性能影响
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摘要
为了研究盐雾干湿循环作用下预应力CFRP加固梁的抗弯性能,采用3.5%NaCl溶液作为干湿循环介质,分别在0次、70次和140次干湿循环次数下,对21根不同CFRP预应力等级的加固梁进行了四点弯曲试验。研究结果表明:当CFRP预应力等级由15%提高至30%时,加固梁的极限荷载分别提高了10.0%和23.0%,延性系数分别提高了28.0%和65.4%,表明预应力CFRP对加固梁抗弯性能的提高有明显效果;在干湿循环作用70次与140次后,30%CFRP预应力等级加固梁的极限荷载分别下降了8.3%和15.7%,延性系数分别下降了7.6%和37.9%,表明盐雾干湿循环次数的增加会对预应力CFRP加固梁的抗弯性能产生显著影响。
In order to analyze the flexural behavior of beams strengthened with prestressed CFRP(carbon fiber reinforced polymer) under the salt spray dry-wet cycles, a 4-point bending test was carried out on 21 beams strengthened with different CFRP prestressing grades, using 3.5% NaCl solution as dry-wet cycling medium with dry-wet cycling times of 0, 70 and 140 respectively. The experimental results showed that with the prestressing grade of CFRP increasing from 15% to 30%, the ultimate load of the strengthened beams was improved by 10% and 23% respectively and the ductility coefficient were improved by 28% and 65.4%. It is indicated that the flexural behavior of the strengthened beams was obviously improved by the prestressed CFRP. After 70 and 140 cycles, the ultimate load of 30% CFRP prestressing grade beams declined by 8.3% and 15.7% respectively and the ductility coefficient declined by 7.6% and 37.9%. It is indicated that the flexural behavior of beams strengthened with prestressed CFRP was influenced significantly by the increasing salt spray dry-wet cycles.
In order to analyze the flexural behavior of beams strengthened with prestressed CFRP(carbon fiber reinforced polymer) under the salt spray dry-wet cycles, a 4-point bending test was carried out on 21 beams strengthened with different CFRP prestressing grades, using 3.5% NaCl solution as dry-wet cycling medium with dry-wet cycling times of 0, 70 and 140 respectively. The experimental results showed that with the prestressing grade of CFRP increasing from 15% to 30%, the ultimate load of the strengthened beams was improved by 10% and 23% respectively and the ductility coefficient were improved by 28% and 65.4%. It is indicated that the flexural behavior of the strengthened beams was obviously improved by the prestressed CFRP. After 70 and 140 cycles, the ultimate load of 30% CFRP prestressing grade beams declined by 8.3% and 15.7% respectively and the ductility coefficient declined by 7.6% and 37.9%. It is indicated that the flexural behavior of beams strengthened with prestressed CFRP was influenced significantly by the increasing salt spray dry-wet cycles.
引文
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[3] 童谷生,李志虎,朱成九,等.预应力碳纤维布材加固混凝土梁的受弯性研究[J].华东交通大学学报,2005,22(2):1-5.
[4] Barros J A O,Fortes A S.Flexural strengthening of concrete beams with CFRP laminates bonded into slits[J].Cement and Concrete Composites,2005,27(4):471-480.
[5] 程东辉,杨燕红.预应力CFRP布加固负载混凝土柱轴心受压性能研究[J].建筑科学与工程学报,2017,34(4):34-40.
[6] Soudki K,El-salakawy E,Craig B.Behavior of CFRP strengthened reinforced concrete beams in corrosive environment[J].Journal of Composites for Construction,2007,11(3):291-298.
[7] Almusallam T H.Load-deflection behavior of RC beams strengthened with GFRP sheets subjected to different environmental conditions[J].Cement Concrete Composites,2006,28(10):879-889.
[8] Toutanji H A,Gómez W.Durability characteristics of concrete beams externally bonded with FRP composite sheets[J].Cement & Concrete Composites,1997,19(4):351-358.
[9] 洪雷,张雨剑,王苏岩.冻融循环作用下CFRP-高强混凝土的界面行为[J].水利与建筑工程学报,2016,14(3):200-205.
[10] 洪雷,马腾龙,王苏岩.湿热环境下预应力CFRP加固高强混凝土的耐久性[J].建筑科学与工程学报,2017,34(1):25-31.
[11] 王苏岩,朱方芳,张红涛,等.持载与湿热环境下CFRP加固高强混凝土梁结构性能研究[J].水利与建筑工程学报,2018,16(3):36-41.
[12] 王苏岩,丁荔,洪雷,等.持载与干湿循环作用下CFRP加固高强混凝土梁耐久性研究[J].建筑结构,2017,47(21):78-83.
[13] 李伟文,徐文冰,周英武,等.硫酸盐溶液干湿循环对FRP加固混凝土梁抗剪性能的劣化作用[J].北京工业大学学报,2014,40(8):1226-1231.
[14] 曲俊龙,洪雷.一种FRP预应力加载试验装置:中国.201820055622.8[P].2018-01-15.
[15] 黄坤.钢筋混凝土梁加固中碳纤维预应力值范围的研究[D].武汉:武汉理工大学,2014:114-115.
[16] 江胜华,侯建国,何英明.预应力碳纤维布加固钢筋混凝土梁的预应力水平的合理取值范围研究[J].建筑技术开发,2008,35(8):35-37.
[17] 万先虎.高温干湿交替环境下FRP-混凝土界面粘结性能的耐久性研究[D].哈尔滨:哈尔滨工业大学,2013:18-28.