ACOUSTIC EMISSION CHARACTERISTICS OF CIRCULAR CONCRETE COLUMNS CONFINED BY BFRP TUBE UNDER CORE CONCRETE IMPOSED AXIAL LOADS
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摘要: 为能够实时监测约束混凝土构件的损伤过程和建立能够预测破坏的预警指标,开展了4个玄武岩纤维增强聚合物(Basalt Fiber Reinforced Polymer,简称BFRP)管约束混凝土圆柱轴心受压下的声发射信号测试试验,并进行了声发射参数的特性研究、关联分析和损伤计算。通过试验,研究不同直径(壁厚相同)、是否配筋等参数对BFRP管约束混凝土圆柱在受力过程中的声发射特征参数变化规律的影响。研究表明:BFRP管约束混凝土圆柱在不同的受力阶段会表现出不同的声发射信号变化特征;在壁厚相等时,直径小的BFRP管约束圆柱,在加载前期的损伤发展相对较慢,而在中后期则会损伤加快并较早破坏;由RA-AF关联分析可知,混凝土内部的张拉裂纹主要出现在弹性阶段,而剪切裂纹主要出现在弹塑性阶段;内部有、无配筋的约束构件均会发生脆性破坏,但是内部配置钢筋会改变约束构件在加载过程中的声发射信号变化规律,从而可以选择某个参数曲线的典型变化特征作为该类构件发生破坏前的预警提示。Abstract: In order to monitor the damage process of confined concrete elements in buildings and establish an early-warning index to predict the failure status in real-time, four experimental tests of circular concrete columns confined by BFRP (Basalt Fiber Reinforced Polymer) tube (CCCBT) were carried out to collect the acoustic emission signals during the loading condition. Meanwhile, the characteristics of acoustic emission parameters, correlation analysis, and damage index calculation were conducted based on the experimental data. The variation of acoustic emission characteristic parameters of CCCBTs, which had different diameters and reinforcement ratios (with the same pipe thickness), was studied through experiments. It was indicated that the CCCBTs presented different characteristics of acoustic emission at different loading stages. The damage development of CCCBTs with smaller diameter (but with identical thickness) was slower relatively at the early loading stage, and then became faster until that the failure appeared. Through the RA-AF correlation analysis, it was concluded that most of tensile cracks formed at the elastic stage, while the shear cracks appeared mainly at the elastic-plastic stage. All the CCCBTs, whether having inner steel reinforcements or not, were brittle failure mode. However, the CCCBTs with inner steel reinforcements altered the variational features of acoustic emission signals. For this reason, some typical variational features could be chosen to predict the hazard ahead of the failure.
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Key words:
- BFRP tube /
- confined concrete /
- circular column /
- acoustic emission /
- inner damage
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[1] 吴晓斌. 玄武岩纤维在土木工程中的应用研究进展[J]. 硅酸盐通报, 2020, 39(4):1043-1049. [2] JIANG S F, ZENG X, SHEN S, et al. Experimental Studies on the Seismic Behavior of Earthquake Damaged Circular Bridge Columns Repaired by Using Combination of Near-Surface-Mounted BFRP Bars with External BFRP Sheets Jacketing[J]. Engineering Structures, 2016, 106(1):317-331. [3] MA G, LI H, YAN L, et al. Testing and Analysis of Basalt FRP-Confined Damaged Concrete Cylinders Under Axial Compression Loading[J]. Construction and Building Materials, 2018, 169(4):762-774. [4] SADEGHIAN P, FILLMORE B. Strain Distribution of Basalt FRP-Wrapped Concrete Cylinders[J]. Case Studies in Construction Materials, 2018, 9(9):1-17. [5] 刘霞, 李峰, 佘殷鹏.玄武岩纤维筋增强珊瑚礁砂混凝土柱轴压试验[J]. 复合材料学报, 2020, 37(10):2428-2438. [6] 高鹏, 黄镜渟, 周安, 等. 玄武岩纤维布和碳纤维布加固高强混凝土柱轴压性能试验研究[J]. 工业建筑, 2019, 49(9):139-144. [7] 纪洪广. 混凝土材料声发射性能研究与应用[M]. 北京:煤炭工业出版社, 2004. [8] ZITTO M E, PIOTRKOWSKIR R, GALLEGO A, et al. Damage Assessed by Wavelet Scale Bands and B-Value in Dynamical Tests of a Reinforced Concrete Slab Monitored with Acoustic Emission[J]. Mechanical Systems and Signal Processing, 2015, 60/61:75-89. [9] 张赛, 吴超. 预应力钢筋混凝土梁损伤过程的声发射信号频带能量特征分析[J]. 安徽建筑大学学报, 2017, 25(4):9-13. [10] 范宇恒. 基于声发射技术的混凝土试件弯曲损伤研究[D]. 北京:北京交通大学, 2017. [11] 门进杰, 赵茜, 朱乐, 等. 基于矩张量的钢筋混凝土构件损伤声发射检测方法[J]. 防灾减灾工程学报, 2017, 37(5):822-841. [12] 李冬生, 杨伟, 喻言. 土木工程结构损伤声发射监测及评定[M]. 北京:科学出版社, 2017. [13] 马高. FRP加固震损RC框架抗震性能试验与损伤评价研究[D]. 哈尔滨:哈尔滨工业大学, 2013. [14] 陈智. FRP-钢管约束混凝土损伤声发射监测及健康诊断[D]. 大连:大连理工大学, 2015. [15] 都方竹. 往复荷载下FRP-钢管约束混凝土损伤声发射监测[D]. 大连:大连理工大学, 2016. [16] 岳健广, 镇东. 受弯钢筋混凝土柱宏/微观损伤演化声发射监测试验与评估研究[J]. 建筑结构学报, 2017, 38(8):156-166. [17] 中国工程建设标准化协会. 约束混凝土柱组合梁框架结构技术规程:CECS 347:2013[S]. 北京:中国建筑工业出版社, 2013. [18] 中华人民共和国住房和城乡建设部.普通混凝土配合比设计规程:JGJ 55-2011[S]. 北京:中国建筑工业出版社, 2011. [19] 韩林海. 钢管混凝土结构:理论与实践[M]. 3版. 北京:科学出版社, 2016. [20] KACHANOV M. Effective Elastic Properties of Cracked Solids:Critical Review of Some Basic Concepts[J]. Applied Mechanics Review, 1992, 45(8):304-335.
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