STUDY ON ANALYTICAL MODEL AND ROBUSTNESS RANKING INDEX OF RC FRAMES WITH UNEQUAL SPANS AGAINST PROGRESSIVE COLLAPSE
-
摘要: 现有钢筋混凝土(RC)框架抗连续倒塌的理论分析模型仅适用于等跨结构。通过理论推导将现有等跨结构的分析模型推广至不等跨结构,并提出了一个新的修正三折线模型,可以考虑不同工况下结构的抗弯、压拱、悬梁线和拉膜效应机制。利用所提理论分析模型建立了一个鲁棒性评判指标,用于危险工况的快速判断。数值与理论结果对比表明:所提出的修正三折线理论分析模型准确性高,能够为不等跨RC框架抗连续倒塌设计提供参考;所建立的鲁棒性评判指标可用于快速确定出RC框架的最危险柱子失效工况。Abstract: The existing analytical models of reinforced concrete (RC) frames against progressive collapse are only available to structures with equal spans. Therefore, a new modified tri-linear model is proposed for RC frames with unequal spans, which can consider the flexural action, compressive arch action, catenary action and tensile membrane action of the structure under different single column loss. A robustness ranking index is also established based on the proposed model to quickly identify the dangerous column loss scenarios. The results show that the proposed model is accurate and can provide a reference for the design of RC frames with unequal spans against progressive collapse. And the robustness ranking index can be used to quickly identify the worst column loss scenarios of RC frames.
-
Key words:
- progressive collapse /
- RC frame /
- unequal span /
- analytical model /
- robustness ranking index
-
图 5 梁压拱机制下的受力模型[15]
Figure 5. Force model of beam specimen
表 1 结构最大荷载因子的理论与数值结果对比
Table 1. Comparisons of analytical and numerical maximum load factor
工况 数值 模型1 相对误差R/(%) 模型2 相对误差R/(%) 模型3 相对误差R/(%) A1 1.90 1.41 25.9 1.56 18.0 1.56 18.0 A2 1.89 1.44 23.9 1.77 6.4 1.90 −0.3 A3 2.07 1.51 27.3 1.84 11.3 1.96 5.2 A4 2.79 1.91 31.4 2.30 17.6 2.47 11.4 A5 2.23 1.49 33.1 1.82 18.2 1.95 12.4 A6 1.53 1.18 22.9 1.44 5.9 1.53 −0.5 B1 4.05 2.58 36.2 3.05 24.7 3.32 18.0 B2 3.52 1.99 43.4 3.00 14.8 3.20 9.0 B3 3.57 2.14 40.1 3.15 12.0 3.35 6.3 B4 4.19 2.34 44.3 3.46 17.4 3.68 12.1 B5 3.45 1.91 44.6 2.89 16.2 3.05 11.4 B6 2.91 1.66 43.1 2.56 12.0 2.72 6.5 表 2 结构鲁棒性评判指标的参数表达式
Table 2. Expression of parameters for structural robustness evaluation index
工况 A B U CC $ \dfrac{{3( {{\chi _y}/{\chi _x} + {\chi _x}/{\chi _y}} ) + 2.5( {1/{\chi _x} + 1/{\chi _y}} )}}{{8{\chi _x}{\chi _y} + 2{\gamma _{\rm{S}}}( {{\chi _x} + {\chi _y}} )}} $ $\dfrac{ { { {\chi _y}/{\chi _x} + {\chi _x}/{\chi _y} } } }{ {3.6[ { {\chi _x}{\chi _y}{\rm{ + } }{\gamma _{\rm{S} } }( { {\chi _x} + {\chi _y} } )/6} ]} }$ 0.02L SC $ \dfrac{{( {8{\chi _y}/{\chi _x} + 2{\chi _x}/{\chi _y}} ) + ( {23/{\chi _x} + 2.5{\alpha _x}/{\chi _y}} )}}{{8{\chi _x}{\chi _y} + 2{\gamma _{\rm{S}}}( {{\chi _x} + {\alpha _x}{\chi _y}} )}} $ $\dfrac{ {8( { {\chi _y}/{\chi _x} } ) + 5/{\chi _x} } }{ {3.6[ { {\chi _x}{\chi _y}{\rm{ + } }{\gamma _{\rm{S} } }( { {\chi _x} + {\chi _y} } )/6} ]} }$ 0.03L PEC $ \dfrac{{( {6{\chi _y}/{\chi _x} + 2{\chi _x}/{\chi _y}} ) + ( {23/{\chi _x} + 2.5{\alpha _x}/{\chi _y}} )}}{{8{\chi _x}{\chi _y} + 2{\gamma _{\rm{S}}}( {{\chi _x} + {\alpha _x}{\chi _y}} )}} $ IC $ \dfrac{{8( {{\chi _y}/{\chi _x} + {\chi _x}/{\chi _y}} ) + 23( {{\alpha _y}/{\chi _x} + {\alpha _x}/{\chi _y}} )}}{{8{\chi _x}{\chi _y} + 2{\gamma _{\rm{S}}}( {{\alpha _y}{\chi _x} + {\alpha _x}{\chi _y}} )}} $ $\dfrac{ {8( { {\chi _y}/{\chi _x} + {\chi _x}/{\chi _y} } ) + 5( { {\alpha _y}/{\chi _x} + {\alpha _x}/{\chi _y} } )} }{ {3.6[ { {\chi _x}{\chi _y}{\rm{ + } }{\gamma _{\rm{S} } }( { {\chi _x} + {\chi _y} } )/6} ]} }$ 0.05L PSC $ \dfrac{{6{\chi _y}/{\chi _x} + 8{\chi _x}/{\chi _y} + 23( {{\alpha _y}/{\chi _x} + {\alpha _x}/{\chi _y}} )}}{{8{\chi _x}{\chi _y} + 2{\gamma _{\rm{S}}}( {{\alpha _y}{\chi _x} + {\alpha _x}{\chi _y}} )}} $ PIC $ \dfrac{{6( {{\chi _y}/{\chi _x} + {\chi _x}/{\chi _y}} ) + 23( {{\alpha _y}/{\chi _x} + {\alpha _x}/{\chi _y}} )}}{{8{\chi _x}{\chi _y} + 2{\gamma _{\rm{S}}}( {{\alpha _y}{\chi _x} + {\alpha _x}{\chi _y}} )}} $ 表 3 参数
$ \gamma $ R、hs1和$ \lambda $ 的敏感性分析Table 3. Sensitivity analysis against
$ \gamma $ R, hs1 and$ \lambda $ 参数 取值 $ \rho $ 建议值 − 0.990 $ \gamma $R 10.00 0.977 25.00 0.988 hs1 0.10 0.976 0.18 0.994 $ \lambda $ 3.00 0.982 5.00 0.993 符号表
. List of symbols
符号 含义 符号 含义 Ab, As 梁截面和板单位宽度截面的受拉钢筋面积 P, P' 结构抗力和外荷载 $f_{\rm{c}}' $ 混凝土抗压强度 qs, qb 板和梁的设计荷载 fy 钢筋屈服强度 Tx, Ty 沿x向和y向板单位宽度的轴拉力 Fx, Fy 沿x向和y向梁的轴拉力 u1 屈服点位移 hb0, hs0 梁和板截面有效高度 u2 过渡段位移 hb1, hs1 梁和板截面受拉钢筋合力点到受压区混凝土中心的高度 u3 失效位移 K 结构抗力刚度 $W_{ {{\rm e}x} }^{\rm{n} }$ 结构设计荷载所做外力虚功 KL 结构荷载因子刚度 $ {W_{{\rm{in}}}} $ 结构内力虚功 L 等效最短梁跨长 αx, αy 沿x轴和y轴的短跨与中心跨之间的比值 Lx, Ly 沿x向和y向梁的总跨长 χx, χy 沿x轴和y轴的梁总跨长与标准跨长L0的比值 LF1, $ {LF_1'} $ 修正前和修正后屈服点对应的荷载因子 γR, γS 描述梁板的抗弯强度比和荷载比的参数 LFD 结构动荷载因子 $ \kappa $ 梁屈服承载力修正因子 Mb 梁的极限抵抗弯矩 λ 描述梁板截面高度比的参数 ms 板的单位宽度极限抵抗弯矩 $ \prod $ 鲁棒性快速评判指标 -
[1] UFC 4-023-03, Design of buildings to resist progressive collapse [S]. Washington, DC: US Department of Defense, 2016. [2] GSA2016, Alternate path analysis and design guidelines for progressive collapse resistance [S]. Washington, DC: US General Services Administration, 2016. [3] CECS 392: 2014, 建筑结构抗倒塌设计规范[S]. 北京: 中国计划出版社, 2015.CECS 392: 2014, Code for anti-collapse design of building structures [S]. Beijing: China Planning Press, 2015. (in Chinese) [4] Yi W J, He Q F, Xiao Y, et al. Experimental study on progressive collapse-resistant behavior of reinforced concrete frame structures [J]. ACI Structural Journal, 2008, 105(4): 433 − 439. [5] Yu J, Tan K H. Structural behavior of RC beam-column subassemblages under a middle column removal scenario [J]. Journal of Structural Engineering, 2013, 139(2): 233 − 250. doi: 10.1061/(ASCE)ST.1943-541X.0000658 [6] 王英, 顾祥林, 林峰. 考虑压拱效应的钢筋混凝土双跨梁竖向承载力分析[J]. 建筑结构学报, 2013, 34(4): 32 − 42.Wang Ying, Gu Xianglin, Lin Feng. Vertical bearing capacity of RC two-bay beams considering compressive arch action [J]. Journal of Building Structures, 2013, 34(4): 32 − 42. (in Chinese) [7] Lu X, Lin K, Li Y, et al. Experimental investigation of RC beam-slab substructures against progressive collapse subject to an edge-column-removal scenario [J]. Engineering Structures, 2017, 149: 91 − 103. doi: 10.1016/j.engstruct.2016.07.039 [8] 凯钱, 李治, 翁运昊, 等. 钢筋混凝土梁-板子结构抗连续性倒塌性能研究[J]. 工程力学, 2019, 36(6): 239 − 247. doi: 10.6052/j.issn.1000-4750.2018.05.0297Qian Kai, Li Zhi, Weng Yunhao, et al. Behavior of RC beam-slab substructures to resist progressive collapse [J]. Engineering Mechanics, 2019, 36(6): 239 − 247. (in Chinese) doi: 10.6052/j.issn.1000-4750.2018.05.0297 [9] 肖宇哲, 李易, 陆新征, 等. 混凝土梁柱子结构连续倒塌动力效应的试验研究[J]. 工程力学, 2019, 36(5): 44 − 52. doi: 10.6052/j.issn.1000-4750.2018.04.0189Xiao Yuzhe, Li Yi, Lu Xinzheng, et al. Experimental study on the dynamic effects in progressive collapse of beam-column concrete substructures [J]. Engineering Mechanics, 2019, 36(5): 44 − 52. (in Chinese) doi: 10.6052/j.issn.1000-4750.2018.04.0189 [10] Bao Y, Kunnath S K, El-Tawil S. Macromodel-based simulation of progressive collapse_ RC frame structures. [J]. Journal of Structural Engineering, 2008, 134(7): 1079 − 1091. doi: 10.1061/(ASCE)0733-9445(2008)134:7(1079) [11] Feng D, Kolay C, Ricles J M, et al. Collapse simulation of reinforced concrete frame structures [J]. The Structural Design of Tall and Special Buildings, 2016, 25(12): 578 − 601. doi: 10.1002/tal.1273 [12] Yu J, Luo L, Li Y. Numerical study of progressive collapse resistance of RC beam-slab substructures under perimeter column removal scenarios [J]. Engineering Structures, 2018, 159: 14 − 27. doi: 10.1016/j.engstruct.2017.12.038 [13] Qian K, Weng Y H, Fu F, et al. Numerical evaluation of the reliability of using single-story substructures to study progressive collapse behaviour of multi-story RC frames [J]. Journal of Building Engineering, 2021, 33: 101636. doi: 10.1016/j.jobe.2020.101636 [14] Yu J, Tan K H. Analytical model for the capacity of compressive arch action of reinforced concrete sub-assemblages [J]. Magazine of Concrete Research, 2014, 66(3): 109 − 126. doi: 10.1680/macr.13.00217 [15] 周育泷, 李易, 陆新征, 等. 钢筋混凝土框架抗连续倒塌的压拱机制分析模型[J]. 工程力学, 2016, 33(4): 34 − 42. doi: 10.6052/j.issn.1000-4750.2015.02.0147Zhou Yulong, Li Yi, Lu Xinzheng, et al. An analytical model of compressive arch action of reinforced concrete frames to resist progressive collapse [J]. Engineering Mechanics, 2016, 33(4): 34 − 42. (in Chinese) doi: 10.6052/j.issn.1000-4750.2015.02.0147 [16] Dat P X, Hai T K, Jun Y. A simplified approach to assess progressive collapse resistance of reinforced concrete framed structures [J]. Engineering Structures, 2015, 101: 45 − 57. doi: 10.1016/j.engstruct.2015.06.051 [17] Zhang J Z, Li G Q, Jiang J. Modeling structural behavior of reinforced concrete beam–slab substructures subject to side-column loss at large deflections [J]. Advances in Structural Engineering, 2017, 21(7): 1051 − 1071. [18] Zhang J Z, Li G Q, Jiang J. Collapse resistance of RC beam–slab subassemblies due to column loss at large deflections [J]. Magazine of Concrete Research, 2019, 71(12): 647 − 663. doi: 10.1680/jmacr.17.00399 [19] Zhang Q, Zhao Y G, Kolozvari K, et al. Simplified model for assessing progressive collapse resistance of reinforced concrete frames under an interior column loss [J]. Engineering Structures, 2020, 215: 110688. doi: 10.1016/j.engstruct.2020.110688 [20] Du K, Bai J, Teng N, et al. Progressive-collapse test of slab effects on reinforced concrete spatial frame substructures [J]. Magazine of Concrete Research, 2021: 1 − 19. [21] Zhong W H, Tan Z, Tian L M, et al. Collapse resistance of composite beam-column assemblies with unequal spans under an internal column-removal scenario [J]. Engineering Structures, 2020, 206: 110143. doi: 10.1016/j.engstruct.2019.110143 [22] He X H C, Yuan X X, Yi W J. Irregularity index for quick identification of worst column removal scenarios of RC frame structures [J]. Engineering Structures, 2019, 178: 191 − 205. doi: 10.1016/j.engstruct.2018.10.026 [23] Izzuddin B A, Vlassis A G, Elghazouli A Y, et al. Progressive collapse of multi-storey buildings due to sudden column loss — Part I: Simplified assessment framework [J]. Engineering Structures, 2008, 30(5): 1308 − 1318. doi: 10.1016/j.engstruct.2007.07.011 [24] Pham X D, Tan K H. Experimental study of beam–slab substructures subjected to a penultimate-internal column loss [J]. Engineering Structures, 2013, 55: 2 − 15. doi: 10.1016/j.engstruct.2013.03.026 [25] Pham A T, Lim N S, Tan K H. Investigations of tensile membrane action in beam-slab systems under progressive collapse subject to different loading configurations and boundary conditions [J]. Engineering Structures, 2017, 150: 520 − 536. doi: 10.1016/j.engstruct.2017.07.060 [26] Park R, Gamble W L. Reinforced concrete slabs [M]. 2nd ed. Hoboken, New Jersey: John Wiley & Sons, 2000. [27] Yu J, Gan Y P, Wu J, et al. Effect of concrete masonry infill walls on progressive collapse performance of reinforced concrete infilled frames [J]. Engineering Structures, 2019, 191: 179 − 193. doi: 10.1016/j.engstruct.2019.04.048 [28] Tan Z, Zhong W H, Tian L M, et al. Numerical study on collapse-resistant performance of multi-story composite frames under a column removal scenario [J]. Journal of Building Engineering, 2021, 44: 102957. doi: 10.1016/j.jobe.2021.102957 [29] Yu J, Gan Y P, Ji J. Behavior and design of reinforced concrete frames retrofitted with steel bracing against progressive collapse [J]. The Structural Design of Tall and Special Buildings, 2020(2): e1771. [30] Shen J, Ren X, Chen J. Effects of spatial variability of ground motions on collapse behaviour of buildings [J]. Soil Dynamics and Earthquake Engineering, 2021, 144: 106668. doi: 10.1016/j.soildyn.2021.106668 [31] 陈泽帆, 林楷奇, 陆新征, 等. RC框架梁柱子结构抗连续倒塌性能不确定性分析[J]. 工程力学, 2021, 38(6): 72 − 80. doi: 10.6052/j.issn.1000-4750.2020.07.0464Chen Zefan, Lin Kaiqi, Lu Xinzheng, et al. Uncertainty analysis on progressive collapse resistance of RC beam-column substructures [J]. Engineering Mechanics, 2021, 38(6): 72 − 80. (in Chinese) doi: 10.6052/j.issn.1000-4750.2020.07.0464 [32] GB 50009−2012, 建筑结构荷载规范[S]. 北京: 中国建筑工业出版社, 2012.GB 50009−2012, Load code for the design of building structures [S]. Beijing: China Architecture & Building Press, 2012. (in Chinese) -