Experimental Research on Stress Relaxation Properties of CFRP Rods

LI Junyu; FANG Zhi; TANG Shoufeng; LIAO Yuan; WANG Zhiwei

doi:10.3724/j.gyjzG24032004

Volume 54 Issue 6

Jun. 2024

Turn off MathJax

Article Contents

Article Navigation > INDUSTRIAL CONSTRUCTION > 2024 > 54(6): 13-21

LI Junyu, FANG Zhi, TANG Shoufeng, LIAO Yuan, WANG Zhiwei. Experimental Research on Stress Relaxation Properties of CFRP Rods[J]. INDUSTRIAL CONSTRUCTION, 2024, 54(6): 13-21. doi: 10.3724/j.gyjzG24032004

Citation:

LI Junyu, FANG Zhi, TANG Shoufeng, LIAO Yuan, WANG Zhiwei. Experimental Research on Stress Relaxation Properties of CFRP Rods[J]. INDUSTRIAL CONSTRUCTION, 2024, 54(6): 13-21. doi: 10.3724/j.gyjzG24032004

Citation:

PDF( 6571 KB)

Experimental Research on Stress Relaxation Properties of CFRP Rods

doi: 10.3724/j.gyjzG24032004

1. College of Civil Engineering, Hunan University, Changsha 410082, China;
2. Hubei Communications Investment Group Co., Ltd., Wuhan 430000, China;
3. Hubei Provincial Communications Planning and Design Institute Co., Ltd., Wuhan 430000, China;
4. Zhongfu Carbon Fiber Core Cable Technology Co., Ltd., Lianyungang 222069, China

Received Date: 2024-03-20
Available Online: 2024-06-24

Abstract

Abstract

In order to determine the relaxation loss of prestressed carbon fiber reinforced polymer (CFRP) rods in the ground anchor abutment of Danjiangkou Reservoir Bridge of Shixi Expressway in Hubei Province, the stress relaxation of CFRP rods under different stress ratios was experimentally studied. Based on the axial tensile test of CFRP rod specimens anchored by bonded anchorage and mechanical crimping anchorage, the influence of different anchorage forms on the failure mode of CFRP rods and the material properties of CFRP rods were clarified; based on the 1 000 h stress relaxation test of CFRP rod specimens, the development laws of stress relaxation of CFRP rods at different stress levels were obtained. The results showed that the specimens anchored by bonded anchorage had an ideal bursting tensile failure under axial tension, but the strain of the specimens changed greatly during the stress relaxation test; the specimens anchored by mechanical crimping anchorage failed prematurely with the mode of the spallation and peeling of the CFRP rods under axial tensile, but the strain of the specimens changed little during the stress relaxation test, which could meet the relevant requirements of the stress relaxation test in GB/T 21839—2019. The stress relaxation of the CFRP rods increased with the increase of the initial stress ratio. The relaxation rates of specimens with initial stress ratios of 0.53, 0.63 and 0.82 were 1.06%, 1.65% and 2.31% after 1 000 h, respectively; the development of stress relaxation of CFRP rods converged rapidly and tended to be more stable with the increase of initial stress. The stress relaxation of specimens with initial stress ratios of 0.53, 0.63 and 0.82 at 24 h were 45.3%, 58.8% and 59.7% of that at 1 000 h, respectively. The stress relaxation of specimens with initial stress ratios of 0.53, 0.63 and 0.82 at 200 h were 78.3%, 81.2% and 82.7% of that at 1 000 h, respectively; based on the test results, the prediction model of stress relaxation in CFRP rods was established with high prediction accuracy, and the relaxation rates of prestressed CFRP rods in ground anchor abutment of Danjiangkou Reservoir Bridge in 10, 30, 50 and 100 years were 1.91%, 2.18%, 2.32% and 2.52%, respectively.
- stress relaxation,
- carbon fiber-reinforced polymer (CFRP) rod,
- anchorage forms,
- initial stress ratio,
- prediction model

FullText(HTML)

References(30)

References

[1]	滕锦光. 新材料组合结构[J]. 土木工程学报, 2018, 51(12):1-11.
[2]	叶列平, 冯鹏. FRP在工程结构中的应用与发展[J]. 土木工程学报, 2006, 39(3):24-36.
[3]	张旷怡. 基于高性能材料大型岩锚体系应用研究[D]. 长沙: 湖南大学, 2015.
[4]	FANG Z, ZHANG K Y, TU B. Experimental investigation of a bond-type anchorage system for multiple FRP tendons[J]. Engineering Structures, 2013, 57:364-373.
[5]	方志, 王常林, 张洪侨,等. 碳纤维绞线在活性粉末混凝土中锚固性能的试验研究[J]. 中国公路学报, 2016, 29(6):198-209.
[6]	BENMOKRANE B, ZHANG B R, CHENNOUF A. Tensile properties and pullout behaviour of AFRP and CFRP rods for grouted anchor applications[J]. Construction & Building Materials, 2000, 14(3):157-170.
[7]	方志, 梁栋, 蒋田勇. 不同粘结介质中CFRP筋锚固性能的试验研究[J]. 土木工程学报, 2006, 39(6):47-51.
[8]	孙胜江, 赵磊, 梅葵花, 等. 钢-玄武岩纤维复合筋混凝土梁受弯试验研究[J]. 桥梁建设, 2021, 51(6):25-30.
[9]	方志, 周建超, 谭星宇. 基于高性能材料的超大跨混合梁斜拉桥结构性能研究[J]. 桥梁建设, 2021, 51(6):76-84.
[10]	罗强, 刘榕, 樊伟, 等. 钢-复合材料组合防撞装置在不同船舶撞击下的性能分析[J]. 桥梁建设, 2020, 50(1):67-73.
[11]	徐世桥, 马如进, 陈艾荣. 大跨悬索桥主缆长期性能评估与分级[J]. 桥梁建设, 2021, 51(5):53-60.
[12]	ZHANG K Y, FANG Z, NANNI A. Behavior of tendons with multiple CFRP rods[J]. Journal of Structural Engineering, 2016, 142(10):86-95.
[13]	ZHANG K Y, FANG Z, NANNI A, et al. Experimental study of a large-scale ground anchor system with FRP tendon and RPC grout medium[J/OL]. Journal of Composites for Construction, 2015, 19(4)[2024-03-20]. https://doi.org/10.16/j.engstruct.2017.11.011.
[14]	袁国青, 董国华, 马剑. FRP筋应力松弛试样端部锚夹方法研究[J]. 玻璃钢/复合材料, 2009(5):3-6.
[15]	孟履祥, 徐福泉, 关建光, 等. 碳纤维筋(CFRP筋)松弛损失试验研究[J]. 施工技术, 2005, 34(7):40-41 , 53.
[16]	ZOU P X W. Long-term properties and transfer length of fiber-reinforced polymers[J]. Journal of Composites for Construction, 2003, 7(1):10-19.
[17]	SAADATMANESH H, TANNOUS F E. Relaxation, creep, and fatigue behavior of carbon fiber reinforced plastic tendons[J]. ACI Structural Journal, 1999, 96(2):143-153.
[18]	SAADATMANESH H, TANNOUS F E. Long-term behavior of aramid fiber reinforced plastic (AFRP) tendons[J]. ACI Materials Journal, 1999, 96(3):297-305.
[19]	ATUTIS E, VALIVONIS J, ATUTIS M. Experimental study of concrete beams prestressed with basalt fiber reinforced polymers. Part II: Stress relaxation phenomenon[J]. Composite Structures, 2018, 18(1):389-396.
[20]	SHI J Z, WANG X, HUANG H, et al. Relaxation behavior of prestressing basalt fiber-reinforced polymer tendons considering anchorage slippage[J]. Journal of Composite Materials, 2017: 51(9):1275-1284.
[21]	HIESCH D, PROSKE T, GRAUBNER C A, et al. Theoretical and experimental investigation of the time-dependent relaxation rates of GFRP and BFRP reinforcement bars[J]. Structural Concrete, 2023, 24(2): 2800-2816.
[22]	中国建筑材料联合会. 纤维增强复合材料筋基本力学性能试验方法:GB/T 30022—2013[S]. 北京:中国标准出版社,2013.
[23]	中国钢铁工业协会. 预应力混凝土用钢材试验方法:GB/T 21839—2019[S]. 北京:中国标准出版社,2019.
[24]	Japan Society of Civil Engineers. Test method for long-term relaxation of continuous fiber reinforcing materials: JSCE-E 534—95[S]. Japan: Japan Society of Civil Engineers, 1995.
[25]	方志, 方川, 蒋正文, 等. 高温后CFRP筋及其粘结式锚固系统的力学性能[J]. 复合材料学报, 2021, 38(12):4031-4041.
[26]	杨小库,王仲奕,路自强,等. 高海拔750 kV变电站防晕金具设计及电场分析[J]. 中国电力, 2011, 11:33-38.
[27]	American Society of Civil Engineers. Standard test method for tensile properties of fiber reinforced polymer matrix composite bars: ASTM-D7205[S]. West Conshohocken: American Society of Civil Engineers International, 2011.
[28]	梁娜,朱四荣,陈建中. 一种新的聚合物基复合材料应力松弛经验模型[J]. 复合材料学报, 2017, 34(10):2205-2210.
[29]	WILLIAMS G, WATTS D C. Non-symmetrical dielectric relaxation behaviour arising from a simple empirical decay function[J]. Transactions of the Faraday Society, 1970, 66: 80-85.
[30]	BETON E. CEB-FIP Model Code 1990[J]. Bulletin Dinformation, 1991, 190:213-214.