INFLUENCE OF AXIAL COMPRESSION RATIO ON SIZE EFFECT OF RC SHEAR WALL UNDER SHEAR FAILURE: MESO-SCALE SIMULATION
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摘要: 剪切破坏是剪力墙破坏的主要模式之一,借助细观数值分析方法对高宽比为1.0的钢筋混凝土(RC)剪力墙的破坏行为进行了分析,研究了轴压比对不同尺寸剪力墙的破坏模式、抗剪承载力、延性、耗能能力等性能的影响,分析了剪力墙剪切破坏的尺寸效应行为,并揭示了轴压比对名义抗剪强度尺寸效应的影响规律。结果表明:不同轴压比作用下的RC剪力墙均发生了明显的剪切破坏,且破坏模式一致;轴压比增大,剪力墙抗剪承载力提高,但延性降低,变形能力下降;随剪力墙尺寸的增大,其名义抗剪强度降低,即存在明显的尺寸效应;轴压比越大,剪切破坏更具脆性,尺寸效应更明显;当剪力墙长度大于1600 mm后,其名义抗剪强度趋于稳定值,尺寸效应逐渐消失。Abstract: Shear failure is one of the main failure modes of shear walls. The failure behavior of reinforced concrete (RC) shear wall with aspect ratio of 1.0 is analyzed by means of meso-scale numerical analysis. The influences of axial compression ratio on failure mode, shear bearing capacity, ductility and energy dissipation capacity of shear walls with different sizes are studied. The size effect in shear failure of shear wall is analyzed, and the influence of axial compression ratio on the size effect of nominal shear strength is also revealed. The results indicate that all the simulated RC shear walls with different axial compression ratios exhibit obvious shear failure. When the axial compression ratio increases, the shear bearing capacity of shear wall increases, but the ductility and the deformation capacity decreases. With the increasing size of shear wall, its nominal shear strength decreases, that is, there is an obvious size effect. The greater the axial compression ratio is, the more brittle the shear failure is and the more obvious the size effect is. And when the length of shear wall is greater than 1600 mm, its nominal shear strength tends to be constant, and the size effect gradually disappears.
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Key words:
- RC shear wall /
- axial compression ratio /
- shear failure /
- size effect /
- meso-scale numerical simulation
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表 1 试件的钢筋性能
Table 1. Properties of steel reinforcements of tested specimens
钢筋类型 钢筋截面面积As/mm2 屈服强度fy/MPa 极限抗拉强度fu/MPa 钢筋弹性模量Es/GPa R6 28.3 421 583.0 211.0 R8 50.3 289 504.5 207.2 T10 73.8 601 644.0 203.0 表 2 粘结滑移曲线中采用的参数
Table 2. Parameters utilized in the bond-slip curve
特征点 粘结应力τ 纵筋相对滑移s 箍筋相对滑移s 开裂cr τcr=2.5ft scr,l=0.025dl scr,t=0.025dt 峰值u τu=3ft su,l=0.04dl su,t=0.04dt 残余r τr=ft sr,l=0.55dl sr,t=0.55dt 注:ft混凝土抗拉强度;dl和dt分别为纵筋和箍筋的直径。 表 3 混凝土细观组分及钢筋力学参数
Table 3. Mechanical parameters of the meso-components of concrete and reinforcing bars
细观组分 抗压强度/MPa 抗拉强度/MPa 断裂能Gc/(J/m2) 弹性模量/GPa 泊松比 屈服强度/MPa 剪胀角Ψ/(°) 偏心率η/(%) 配筋率ρh/(%) K 骨料 − − − ★70 ★0.2 − − − − − 砂浆基质 ★36.17 ★3.01 48 ★22.1 ★0.2 − 30 0.1 − 0.667 界面过渡区 ☆28.94 ☆2.52 28 ☆20.68 ☆0.2 − 30 0.1 − 0.667 水平分布钢筋 − − − ★207.2 ★0.3 ★289 − − 1.4 − 注:★为试验实测值;☆为反复试算选值;其他力学数据为默认值。 表 4 尺寸效应律拟合参数
Table 4. Fitting parameters of size effect law
编号 剪力墙抗剪强度vu 经验系数v0 经验系数d0 lg(d/d0) lg (vu/v0) 600-0 3.567 3.624 3805 −0.802 −0.007 800-0 3.370 − − −0.677 −0.032 1200-0 3.049 − − −0.501 −0.075 1600-0 3.003 − − −0.376 −0.082 2400-0 2.997 − − −0.200 −0.083 600-1 4.136 4.311 2690 −0.652 −0.018 800-1 3.836 − − −0.527 −0.051 1200-1 3.481 − − −0.351 −0.093 1600-1 3.360 − − −0.226 −0.108 2400-1 3.284 − − −0.050 −0.118 600-2 4.783 5.070 1945 −0.511 −0.025 800-2 4.433 − − −0.386 −0.058 1200-2 3.836 − − −0.210 −0.121 1600-2 3.758 − − −0.085 −0.130 2400-2 3.634 − − 0.091 −0.145 600-4 5.963 6.154 1320 −0.342 −0.014 800-4 5.217 − − −0.217 −0.072 1200-4 4.278 − − −0.041 −0.158 1600-4 4.172 − − 0.084 −0.169 2400-4 4.191 − − 0.260 −0.167 注:试件编号600、800、1200、1600和2400代表剪力墙的长度;0、1、2、和4代表轴压比为0、0.1、0.2和0.4。 -
[1] Davood M, Maryam M A. Effect of confining of boundary elements of slender RC shear wall by FRP composites and stirrups [J]. Engineering Structures, 2012, 41: 1 − 13. doi: 10.1016/j.engstruct.2012.03.019 [2] Salonikios T N, Kappos A J, Tegos I A, et al. Cyclic load behavior of low-slenderness R/C walls: Design basis and test results [J]. ACI Structural Journal, 1999, 96(4): 649 − 660. [3] Paulay T, Priestley M J N, Synge A J. Ductility in earthquake resisting squat shear walls [J]. ACI Journal, 1982, 79(4): 257 − 269. [4] Hwang S J, Fang W H, Lee H J, et al. Analytical model for predicting shear strength of squat walls [J]. Journal of Structural Engineering, 2001, 127(1): 43 − 50. doi: 10.1061/(ASCE)0733-9445(2001)127:1(43) [5] Li B, Qian K, Wu H. Flange effects on seismic performance of reinforced concrete squat walls with irregular or regular openings [J]. Engineering Structures, 2016, 110: 127 − 144. doi: 10.1016/j.engstruct.2015.11.051 [6] Peng Y, Wu H, Zhuge Y. Strength and drift capacity of squat recycled concrete shear walls under cyclic loading [J]. Engineering Structures, 2015, 100: 356 − 368. doi: 10.1016/j.engstruct.2015.06.025 [7] Bekő A, Rosko P, Wenzel H, et al. RC shear walls: Full scale cyclic test, insights and derived analytical model [J]. Engineering Structures, 2015, 102: 120 − 131. doi: 10.1016/j.engstruct.2015.07.053 [8] Athanasopoulou M. Shear strength and drift capacity of reinforced concrete and high-performance fiber reinforced concrete low-rise walls subjected to displacement reversals [D]. Ann Arbor, MI, USA: University of Michigan, 2010. [9] Luna B, Rivera J, Whittaker A. Seismic behavior of low-aspect-ratio reinforced concrete shear walls [J]. ACI Structural Journal, 2015, 112: 593 − 604. [10] JGJ 3−2010, 高层建筑混凝土结构技术规程[S]. 北京: 中国建筑工业出版社, 2010.JGJ 3−2010, Technical specification for concrete structures of tall building [S]. Beijing: China Architecture & Building Press, 2010. (in Chinese) [11] Looi D T W, Su R K L, Cheng B, et al. Effects of axial load on seismic performance of reinforced concrete walls with short shear span [J]. Engineering Structures, 2012, 28(Suppl 1): 312 − 326. doi: 10.1016/j.engstruct.2017.08.030 [12] Lefas L D, Kotsovos M K, Ambraseys N N. Behavior of reinforced concrete structural walls: Strength, deformation characteristics, and failure mechanism [J]. ACI Structural Journal, 1990, 87(1): 12 − 31. [13] Li W, Li Q. Seismic performance of L-shaped RC shear wall subjected to cyclic loading [J]. Structural Design of Tall & Special Buildings, 2012, 21: 855 − 866. [14] Kang S M, Kim J Y. Evaluation of deformation capacity including yield deformation in displacement-based design of special RC shear wall [J]. Structural Design of Tall & Special Buildings, 2014, 23: 181 − 209. [15] Rasoolinejad M, Bažant Z P. Size effect of squat shear walls extrapolated by microplane model M7 [J]. ACI Structural Journal, 2019, 116(3): 75 − 84. [16] Rios R D, Riera J D. Size effects in the analysis of reinforced concrete structures [J]. Engineering Structures, 2004, 26(8): 1115 − 1125. doi: 10.1016/j.engstruct.2004.03.012 [17] Li W J, Guo L. Meso-fracture simulation of cracking process in concrete incorporating three-phase characteristics by peridynamic method [J]. Construction and Building Materials, 2018, 161: 665 − 675. doi: 10.1016/j.conbuildmat.2017.12.002 [18] Wriggers P, Moftah S O. Mesoscale models for concrete: Homogenisation and damage behavior [J]. Finite Elements in Analysis and Design, 2006, 42: 623 − 636. doi: 10.1016/j.finel.2005.11.008 [19] Meddah M S, Zitouni S, Belâabes S. Effect of content and particle size distribution of coarse aggregate on the compressive strength of concrete [J]. Construction and Building Materials, 2010, 24(4): 505 − 512. doi: 10.1016/j.conbuildmat.2009.10.009 [20] Jin L, Wang T, Jiang X A, et al. Size effect in shear failure of RC beams with stirrups: Simulation and formulation [J]. Engineering Structures, 2019, 199: 109573. doi: 10.1016/j.engstruct.2019.109573 [21] Jin L, Li D, Du X L, et al. Experimental and numerical study on size effect in eccentrically loaded stocky RC columns [J]. ASCE Journal of Structural Engineering, 2017, 143(2): 04016170. doi: 10.1061/(ASCE)ST.1943-541X.0001655 [22] GB 50010−2010, 混凝土结构设计规范[S]. 北京: 中国建筑工业出版社, 2010.GB 50010−2010, Code for design of concrete structures [S]. Beijing: China Architecture & Building Press, 2010. (in Chinese) [23] Lee J, Fenves G L. Plastic-damage model for cyclic loading of concrete structures [J]. ASCE Journal of Engineering Mechanics, 1998, 124(8): 892 − 900. doi: 10.1061/(ASCE)0733-9399(1998)124:8(892) [24] Jin L, Ding Z, Li D, et al. Experimental and numerical investigations on the size effect of moderate high-strength reinforced concrete columns under small-eccentric compression [J]. International Journal of Damage Mechanics, 2017: 657 − 685. [25] Rodrigues H, Arêde A, Varum H, et al. Experimental evaluation of rectangular reinforced concrete column behaviour under biaxial cyclic loading [J]. Earthquake Engineering & Structural Dynamics, 2013, 42(2): 239 − 259. [26] 叶露, 王宇航, 石宇, 等. 冷弯薄壁型钢框架-开缝钢板剪力墙力学性能研究[J]. 工程力学, 2020, 37(11): 156 − 166. doi: 10.6052/j.issn.1000-4750.2020.01.0005Ye Lu, Wang Yuhang, Shi Yu, et al. Study on the mechanical properties of cold-formed steel framed shear wall with slits [J]. Engineering Mechanics, 2020, 37(11): 156 − 166. (in Chinese) doi: 10.6052/j.issn.1000-4750.2020.01.0005 [27] Jin L, Li D, Du X L. Mechanical behavior and size effect of moderate high-strength RC columns under monotonic and cyclic axial compression [J]. Engineering Structures, 2016, 124: 269 − 285. doi: 10.1016/j.engstruct.2016.06.030 [28] 谢岳峻. 低剪跨比钢筋混凝土剪力墙抗震性能试验研究[D]. 广州: 华南理工大学, 2018.Xie Yuejun. Experimental study on seismic behaviour of low-rise reinforced concrete shear walls [D]. Guangzhou: South China University of Technology, 2018. (in Chinese) [29] 韩小雷, 陈彬彬, 崔济东, 等. 钢筋混凝土剪力墙变形性能指标试验研究[J]. 建筑结构学报, 2018, 39(6): 1 − 9.Han Xiaolei, Chen Binbin, Cui Jidong, et al. Experimental study on deformation performance indexes of RC shear walls [J]. Journal of Building Structures, 2018, 39(6): 1 − 9. (in Chinese) [30] Salonikios T N. Shear strength and deformation patterns of R/C walls with aspect ratio 1.0 and 1.5 designed to Eurocode 8 (EC8) [J]. Engineering Structures, 2002, 24(1): 39 − 49. doi: 10.1016/S0141-0296(01)00076-1 [31] Bažant Z P, Kim J K. Size effect in shear failure of longitudinally reinforced beams [J]. Journal of the American Concrete Institute, 1984, 81(5): 456 − 468. [32] 任重翠, 肖从真, 徐培福, 等. 钢筋混凝土剪力墙拉压变轴力低周往复受剪试验研究[J]. 土木工程学报, 2018, 51(5): 16 − 25.Ren Chongcui, Xiao Congzhen, Xu Peifu, et al. Low-cyclic repeated shear test on tension-compression variable axial force of reinforced concrete shear wall [J]. China Civil Engineering Journal, 2018, 51(5): 16 − 25. (in Chinese) [33] 抗剪强度专题研究组. 钢筋混凝土框架柱的抗剪强度[J]. 建筑结构学报, 1987(3): 25 − 37.Research Group on Shear Strength. Shear strength of reinforced concrete columns [J]. Journal of Building Structures, 1987(3): 25 − 37. (in Chinese) -