Seismic vulnerability analysis of pile-supported wharves based on displacement
-
摘要: 鉴于目前高桩码头的地震易损性分析很少将码头的总位移作为性能指标,分别根据云图法和条带法建立了基于位移的码头地震易损性分析方法。该方法考虑地震动的不确定性,并基于桩身材料应变限值定义了码头的破坏状态。为了说明这种分析方法,采用80条地震动记录对一高桩码头案例分别进行了云图法和条带法分析,比较了两种方法建立的易损性曲线的差别,分析了位移能力不确定性对易损性曲线的影响。结果表明,由云图法和条带法建立的码头易损性曲线之间的差别较小,可以忽略,但考虑到云图法的计算量较小,建议在码头易损性分析中采用云图法;位移能力不确定性对于易损性曲线的影响较大,分析中不可忽略,应予以考虑。Abstract: In view of the fact that the total displacement of the wharf is seldom used as a performance index in the seismic vulnerability analysis of the pile-supported wharf at present, a displacement-based vulnerability analysis method is proposed based on the cloud map method and stripe method respectively. The proposed method takes into account the uncertainty of earthquake ground motion and defines the failure status of the pile-supported wharf based on the strain limits of pile material. In order to illustrate this analysis method, 80 earthquake records are used to analyze the vulnerability curves of the pile-supported wharf by using the cloud map method and stripe method respectively. The differences between the vulnerability curves given by two methods are compared, and the influences from the uncertainty of displacement capacity on the vulnerability curves are analyzed. The analysis results show that there is little difference between the vulnerability curves of wharves established by the cloud map method and the stripe method, which can be neglected. However, considering the small amount of calculation of the cloud map method, it is suggested to use the cloud map method in the vulnerability analysis of wharves. The uncertainty of displacement capacity plays an important role in the analysis of the vulnerability curves, and should not be neglected in the analysis and should be taken into account.
-
表 1 码头破坏状态
Table 1. Damage states of wharves
破坏状态 桩顶塑性铰 地基土内桩塑性铰 地基深处桩塑性铰 Ⅰ-最小破坏 εc≤0.005, εs≤0.015 εc≤0.005 εc≤0.008 Ⅱ-可控且可修复的破坏 εc≤0.025, εs≤0.060 εc≤0.008 εc≤0.012 Ⅲ-可保障生命安全的破坏 εs≤0.080 εc≤0.012 无限值 表 2 各土层特性参数
Table 2. Characteristic parameters of various soil layers
土层名称 天然重度/(kN·m-3) 有效重度/(kN·m-3) 内摩擦角/° 块石 17.0 10.0 45.0 回填砂 18.0 9.5 32.0 细中砂 18.2 9.2 32.1 中砂 18.5 10.0 34.0 粗砂 18.6 10.5 36.0 砾砂 18.8 11.1 38.2 表 3 不同地震动强度水平下μD和βD的取值
Table 3. Values for μD and βD under different values of aPG
μD/cm βD 0.10g 0.20g 0.30g 0.40g 0.50g 0.60g 0.70g 0.10g 0.20g 0.30g 0.40g 0.50g 0.60g 0.70g 0.88 1.90 2.98 4.15 5.42 6.76 8.16 0.368 8 0.380 5 0.388 3 0.407 5 0.426 0 0.438 4 0.448 3 表 4 不同易损性分析方法和βC的结果对比
Table 4. Comparison between results given by various vulnerability analysis methods andβC
地震动强
度水平不同易损性分析方法 不同βC 破坏状态Ⅰ 破坏状态Ⅱ 破坏状态Ⅲ 破坏状态Ⅰ 破坏状态Ⅱ 破坏状态Ⅲ P1 P2 P1 P2 P1 P2 P2 P′2 P2 P′2 P2 P′2 0.10g 0.006 38 0.007 82 5.9×10-7 2.8×10-6 3.0×10-8 2.3×10-7 0.007 82 0.001 69 2.8×10-6 1.8×10-8 2.3×10-7 7.8×10-10 0.20g 0.198 11 0.184 90 0.000 76 0.001 27 0.000 01 0.000 22 0.184 90 0.138 36 0.001 27 0.000 13 0.000 22 9.7×10-6 0.30g 0.534 41 0.497 03 0.013 68 0.016 61 0.002 98 0.004 24 0.497 03 0.496 40 0.016 61 0.004 90 0.004 24 0.000 71 0.40g 0.769 25 0.733 56 0.068 51 0.067 01 0.022 03 0.022 70 0.733 56 0.775 28 0.067 01 0.034 59 0.022 70 0.007 62 0.50g 0.890 19 0.867 17 0.175 73 0.156 51 0.074 49 0.065 33 0.867 17 0.911 49 0.156 51 0.110 54 0.065 33 0.033 39 0.60g 0.947 45 0.934 86 0.309 49 0.271 27 0.158 92 0.133 16 0.934 86 0.966 75 0.271 27 0.230 08 0.133 16 0.088 81 0.70g 0.974 08 0.967 93 0.443 82 0.393 25 0.262 63 0.219 64 0.967 93 0.987 62 0.393 25 0.371 27 0.219 64 0.174 11 ∑(P1-P2)2 0.003 57 0.004 40 0.002 60 - - - ∑(P2-P′2)2 - - - 0.007 31 0.005 48 0.005 30 -
[1] 高树飞, 贡金鑫, 冯云芬.国内外高桩码头抗震性能和设计方法研究进展Ⅰ:震害和抗震设计方法[J].水利水运工程学报, 2016(6): 1-8. http://slsygcxb.cnjournals.org/ch/reader/view_abstract.aspx?file_no=201606001&flag=1 GAO Shufei, GONG Jinxin, FENG Yunfen. Advances in research on seismic performance and design methods for pile-supported wharves Part Ⅰ: Earthquake damage and seismic design methods[J]. Hydro-Science and Engineering, 2016(6): 1-8. (in Chinese) http://slsygcxb.cnjournals.org/ch/reader/view_abstract.aspx?file_no=201606001&flag=1 [2] HEIDARY-TORKAMANI H, BARGI K, AMIRABADI R, et al. Fragility estimation and sensitivity analysis of an idealized pile-supported wharf with batter piles[J]. Soil Dynamics and Earthquake Engineering, 2014, 61/62(2): 92-106. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=c70aea456519287e60973fe9670e5c17 [3] SHAFIEEZADEH A. Seismic vulnerability assessment of wharf structures[D]. Atlanta: Georgia Institute of Technology, 2011. [4] CHIOU J S, CHIANG C H, YANG H H, et al. Developing fragility curves for a pile-supported wharf[J]. Soil Dynamics and Earthquake Engineering, 2011, 31(5): 830-840. http://cn.bing.com/academic/profile?id=3b8bcaaf7ac98b48e3894781b238e3ee&encoded=0&v=paper_preview&mkt=zh-cn [5] YANG C S W, DESROCHES R, RIX G. Numerical fragility analysis of vertical-pile-supported wharves in the western United States[J]. Journal of Earthquake Engineering, 2012, 16(4): 579-594. doi: 10.1080/13632469.2011.641063 [6] THOMOPOULOS C, LAI C G. Preliminary definition of fragility curves for pile-supported wharves[J]. Journal of Earthquake Engineering, 2012, 16(Suppl1): 83-106. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=10.1080/13632469.2012.675839 [7] HEIDARY-TORKAMANI H, BARGI K, AMIRABADI R. Fragility curves derivation for a pile-supported wharf[J]. International Journal of Maritime Technology, 2013, 1(1): 1-10. [8] AMIRABADI R, BARGI K, PIROZ M D, et al. Determination of optimal probabilistic seismic demand models for pile-supported wharves[J]. Structure and Infrastructure Engineering, 2014, 10(9): 1119-1145. doi: 10.1080/15732479.2013.793723 [9] HEIDARY-TORKAMANI H, BARGI K, AMIRABADI R. Seismic vulnerability assessment of pile-supported wharves using fragility curves[J]. Structure and Infrastructure Engineering, 2014, 10(11): 1417-1431. doi: 10.1080/15732479.2013.823453 [10] SHAH D. Fragility analysis of pile supported wharf using performance based design[D]. Ahmedabad: Gujarat Technological University, 2016. [11] 于晓辉, 吕大刚.基于云图-条带法的概率地震需求分析与地震易损性分析[J].工程力学, 2016(6): 68-76. http://www.cnki.com.cn/Article/CJFDTotal-GCLX201606009.htm YU Xiaohui, LÜ Dagang. Probabilistic seismic demand analysis and seismic fragility analysis based on a cloud-stripe method[J]. Engineering Mechanics, 2016(6): 68-76. http://www.cnki.com.cn/Article/CJFDTotal-GCLX201606009.htm [12] MACKIE K R, STOJADINOVI B. Comparison of incremental dynamic, cloud, and stripe methods for computing probabilistic seismic demand models[C]//Proceedings of the 2005 Structures Congress and 2005 Forensic Engineering Symposium, New York, 2005. [13] WEN Y K, ELLINGWOOD B R, BRACCI J M. Vulnerability function framework for consequence-based engineering[R]. Urbana: University of Illinois at Urbana-Champaign, 2004. [14] KWON O S, ELNASHAI A. The effect of material and ground motion uncertainty on the seismic vulnerability curves of RC structure[J]. Engineering structures, 2006, 28(2): 289-303. doi: 10.1016/j.engstruct.2005.07.010 [15] COMELL C A, JALAYER F, HAMBURGER R O, et al. Probabilistic basis for 2000 SAC federal emergency management agency steel moment frame guidelines[J]. Journal of Structural Engineering, 2002, 128(4): 526-533. doi: 10.1061/(ASCE)0733-9445(2002)128:4(526) [16] ASCE/COPRI 61-14 Seismic design of piers and wharves [S]. [17] API RP 2A-WSD-2005 Recommended practice for planning, designing and constructing fixed offshore platforms—working stress design[S]. [18] CHIOU J S, YANG H H, CHEN C H. Plastic hinge setting for nonlinear pushover analysis of pile foundations[C]//The 14th World Conference on Earthquake Engineering, Beijing, 2008. [19] SHOME N, COMELL C A. Probabilistic seismic demand analysis of nonlinear structures[R]. Stanford: Stanford University, 1999. -