EXPERIMENTAL STUDY ON SHEAR AND BENDING BEHAVIOR OF MAIN-CROSS TEE JOINTS OF SUSPENDED CEILING
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摘要: 近年发生的地震中吊顶的震害显著,主次龙骨节点失效是吊顶破坏的主要原因之一。为评估吊顶主次龙骨节点的受剪和受弯性能,对其开展单调加载和低周往复加载试验,考察了节点的破坏模式、承载力、变形能力、滞回性能和耗能能力,建立了节点的易损性曲线。研究结果表明:主次龙骨节点主轴受剪和次轴受剪的破坏模式分别为节点剪切破坏和节点面外弯曲并脱出,主次龙骨节点受弯的破坏模式是节点脆性脱出破坏。对比节点主轴受剪,节点次轴受剪时强度更低,但节点变形能力更强。对比节点主轴受弯,节点次轴受弯时强度更高,但节点转动能力稍低。主次龙骨节点受剪和受弯时的荷载-位移滞回曲线捏拢效应显著,耗能能力不强。易损性分析表明,主次龙骨节点次轴受剪和主轴受弯时更容易破坏。Abstract: The suspended ceiling system (SCS) experienced obvious damage during earthquakes in recent years, and the failure of the main-cross tee joints is one of the major reasons for the ceiling damage. A series of tests on main-cross tee joints under monotonic and cyclic loadings were conducted to investigate the shear and bending behaviors of the main-cross tee joints. The failure modes, load-bearing ability, deformation capacity, hysteretic behavior, and energy dissipation capability of the joints were investigated, and the fragility curves of the joints were established. The test results indicate that the failure modes of the main-cross tee joints in the strong and weak axes under shear loading are the shear failure and out-of-plane bending and separation failure of the joints, respectively. The brittle separation from the grid is the failure mode of main-cross tee joints under bending loading. Compared with the shear capacity of the joints in the strong axis, the joint strength is lower but the deformation ability of the joints is stronger in the weak axis in the shear test. Compared with the bending capacity of the joints in the strong axis, the joint strength is greater but the rotation ability of the joints is slightly lower in the weak axis in the bending test. Whether under bending or shearing loadings, the pinching effect of the load-displacement hysteretic curve of the joints is significant, and the energy dissipation capacity is limited. The fragility analysis shows that the main-cross tee joint is more vulnerable when the weak axis of the joint is subjected to a shear force or the strong axis of the joint is subjected to a bending moment.
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Key words:
- suspended ceiling /
- main-cross tee joint /
- shear test /
- bending test /
- fragility analysis
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表 1 试件的综合信息
Table 1. General information of specimens
试件
对象试验
类型加载
类型加载方向 数量 试件编号 主
次
龙
骨
节
点受剪
试验正向 主轴 3 CJS-A1-C1
CJS-A1-C2
CJS-A1-C3负向 3 CJS-A2-C1
CJS-A2-C2
CJS-A2-C3低周往复 3 CJS-A3-C1
CJS-A3-C2
CJS-A3-C3正向 次轴 3 CJS-B1-C1
CJS-B1-C2
CJS-B1-C3负向 3 CJS-B2-C1
CJS-B2-C2
CJS-B2-C3低周往复 3 CJS-B3-C1
CJS-B3-C2
CJS-B3-C3受弯
试验正向 主轴 2 CJB-A1-C1
CJB-A1-C2负向 2 CJB-A2-C1
CJB-A2-C2低周往复 3 CJB-A3-C1
CJB-A3-C2
CJB-A3-C3正向 次轴 2 CJB-B1-C1
CJB-B1-C2负向 2 CJB-B2-C1
CJB-B2-C2低周往复 3 CJB-B3-C1
CJB-B3-C2
CJB-B3-C3表 2 主次龙骨节点的受剪试验结果
Table 2. Test results of main-cross tee joints during shear tests
试验对象 试验类型 加载类型 加载方向 $ \mathop F\nolimits_{\rm p}^ + $ $ \mathop D\nolimits_{\rm p}^ + $ $ \mathop F\nolimits_{\rm p}^ - $ $ \mathop D\nolimits_{\rm p}^ - $ 主次龙骨
节点受剪
试验正向 主轴 1062 12.0 − − 负向 − − 1064 11.0 低周往复 1012 11.2 1222 11.9 正向 次轴 928 32.3 − − 负向 − − 809 27.4 低周往复 359 15.0 367 16.1 注:荷载$ F $和位移$ D $的单位分别为N和mm;$ \mathop F\nolimits_{\rm p}^ + $和$\mathop F\nolimits_{\rm p}^ -$分别为正向和负向峰值荷载;$ \mathop D\nolimits_{\rm p}^ + $和$ \mathop D\nolimits_{\rm p}^ - $分别为正向和负向峰值荷载对应的位移。 表 3 主次龙骨节点的受弯试验结果
Table 3. Test results of main-cross tee joints during bending tests
试验对象 试验类型 加载类型 加载方向 $ \mathop M\nolimits_{\rm p}^ + $ $ \mathop \theta \nolimits_{\rm p}^ + $ $ \mathop M\nolimits_{\rm p}^ - $ $ \mathop \theta \nolimits_{\rm p}^ - $ 主次龙骨
节点受弯试验 正向 主轴 9.435 0.200 − − 负向 − − 7.990 0.255 低周往复 9.605 0.237 6.035 0.254 正向 次轴 45.752 0.299 − − 负向 − − 28.220 0.213 低周往复 23.035 0.216 22.988 0.181 注:弯矩$ M $和转角$ \theta $的单位分别为kN·mm和rad;$ \mathop M\nolimits_{\rm p}^ + $和$ \mathop M\nolimits_{\rm p}^ - $分别为正向和负向峰值弯矩;$ \mathop \theta \nolimits_{\rm p}^ + $和$ \mathop \theta \nolimits_{\rm p}^ - $分别为正向和负向峰值弯矩对应的转角。 表 4 主次龙骨节点的易损性参数
Table 4. Fragility parameters of main-cross tee joints
试验对象 试验类型 加载方向 DS1 ${x_{\rm m}}$ $ \beta $ 主次龙骨
节点受剪试验 主轴 1.037 0.254 次轴 0.312 0.313 受弯试验 主轴 7.967 0.361 次轴 19.512 0.269 注:受剪试验对应的数据单位为kN;受弯试验对应的数据单位为kN·mm。 -
[1] Miranda E, Mosqueda G, Retamales R, et al. Performance of nonstructural components during the 27 February 2010 Chile earthquake [J]. Earthquake Spectra, 2012, 28(Suppl 1): S453 − S471. [2] Dhakal R P, Macrae G A, Hogg K. Performance of ceilings in the February 2011 Christchurch earthquake [J]. Bulletin of the New Zealand Society for Earthquake Engineering, 2011, 44(4): 377 − 387. doi: 10.5459/bnzsee.44.4.377-387 [3] 李戚齐, 曲哲, 解全才, 等. 我国公共建筑中吊顶的震害特征及其易损性分析[J]. 工程力学, 2019, 36(7): 207 − 215. doi: 10.6052/j.issn.1000-4750.2018.10.0358Li Qiqi, Qu Zhe, Xie Quancai, et al. Seismic damage characteristics and fragility of suspended ceilings in Chinese public buildings [J]. Engineering Mechanics, 2019, 36(7): 207 − 215. (in Chinese) doi: 10.6052/j.issn.1000-4750.2018.10.0358 [4] Qi L, Kurata M, Ikeda Y, et al. Seismic evaluation of two-elevation ceiling system by shake table tests [J]. Earthquake Engineering & Structural Dynamics, 2020: 1 − 20. [5] 黄宝锋, 华夏, 卢文胜. 浮放花瓶动力反应机理与振动台试验研究[J]. 工程力学, 2020, 37(8): 112 − 122. doi: 10.6052/j.issn.1000-4750.2019.09.0536Huang Baofeng, Hua Xia, Lu Wensheng. Seismic response behavior and shaking table tests on freestanding vase [J]. Engineering Mechanics, 2020, 37(8): 112 − 122. (in Chinese) doi: 10.6052/j.issn.1000-4750.2019.09.0536 [6] 尚庆学, 郑迦译, 李吉超, 等. 各国规范对于楼面峰值加速度规定的对比研究[J]. 工程力学, 2020, 37(增刊 1): 91 − 96. doi: 10.6052/j.issn.1000-4750.2019.05.S013Shang Qingxue, Zheng Jiayi, Li Jichao, et al. Comparative study of relevant specifications on peak floor acceleration in current codes of different countries [J]. Engineering Mechanics, 2020, 37(Suppl 1): 91 − 96. (in Chinese) doi: 10.6052/j.issn.1000-4750.2019.05.S013 [7] Zhou T, Wang X, Liu W, et al. Shaking table tests on seismic response of discontinuous suspended ceilings [J]. Journal of Building Engineering, 2021: 102916. [8] Soroushian S, Rahmanishamsi E, Ryu K P, et al. Experimental fragility analysis of suspension ceiling systems [J]. Earthquake Spectra, 2016, 32(2): 881 − 908. doi: 10.1193/071514eqs109m [9] Jiang H J, Wang Y, Kasai K, et al. Shaking table tests on Chinese style suspended ceiling systems [C]// 17th World Conference on Earthquake Engineering. Sendai, Japan, International Association for Earthquake Engineering, 2020. [10] Paganotti G, Dhakal R, Macrae G. Development of typical NZ ceiling system seismic fragilities [C]// Proceedings of the Ninth Pacific Conference on Earthquake Engineering. Auckland, New Zealand, New Zealand Society for Earthquake Engineering, 2011. [11] Dhakal R P, Macrae G A, Pourali A, et al. Seismic fragility of suspended ceiling systems used in NZ based on component tests [J]. Bulletin of the New Zealand Society for Earthquake Engineering, 2016, 49(1): 45 − 63. doi: 10.5459/bnzsee.49.1.45-63 [12] Pourali A. Seismic performance of suspended ceilings [D]. Christchurch: University of Canterbury, 2017. [13] Soroushian S, Maragakis E M, Jenkins C. Capacity evaluation of suspended ceiling components, part 1: Experimental studies [J]. Journal of Earthquake Engineering, 2015, 19(5-6): 784 − 804. [14] Soroushian S, Maragakis E M, Jenkins C. Capacity evaluation of suspended ceiling components, part 2: Analytical studies [J]. Journal of Earthquake Engineering, 2015, 19(5-6): 805 − 821. [15] Soroushian S, Maragakis M, Jenkins C. Axial capacity evaluation for typical suspended ceiling joints [J]. Earthquake spectra, 2016, 32(1): 547 − 565. doi: 10.1193/123113EQS301M [16] 宋喜庆. 矿棉板吊顶关键节点抗震性能研究 [D]. 哈尔滨: 哈尔滨理工大学, 2018.Song Xiqing. Seismic performance of key joint in mineral wool board suspended ceiling [D]. Harbin: Harbin University of Science and Technology, 2018. (in Chinese) [17] Retamales R, Mosqueda G, Filiatrault A, et al. New experimental capabilities and loading protocols for seismic qualification and fragility assessment of nonstructural components [R]. Buffalo: State University of New York at Buffalo, 2008. [18] Porter K, Kennedy R, Bachman R. Creating fragility functions for performance-based earthquake engineering [J]. Earthquake Spectra, 2007, 23(2): 471 − 489. doi: 10.1193/1.2720892 [19] FEMA P-58-2, Seismic performance assessment of buildings volume 2: implementation guide [S]. Washington: Federal Emergency Management Agency, 2012. -