共查询到19条相似文献,搜索用时 251 毫秒
1.
为进行基于能力谱法的结构地震易损性分析,采用选定的250条地震波对单自由度结构进行了弹塑性时程分析和弹性时程分析,建立了结构弹塑性时程分析最大位移与Pushover分析最大位移比的平均值和变异系数与相关参数的关系式,其中Pushover分析中的需求谱采用的是按相同地震波进行弹性时程分析建立的反应谱;通过Monte-Carlo方法分析了随机结构参数下Pushover分析得到的最大位移的概率特性,给出了最大位移平均值和变异系数的表达式;采用可靠度计算理论,给出了结构易损概率的计算公式和可靠指标的简化计算公式。结果表明:提出的易损性分析方法通过Pushover分析实现了传统结构易损性分析方法需要进行大量弹塑性时程计算才能达到的目标。 相似文献
2.
3.
4.
随着基于性能抗震设计理论的提出,以及对结构弹塑性地震反应研究的深入,弹塑性反应谱的研究得到更多的重视与发展。文中首先阐明了弹性和弹塑性反应谱的基本概念;其次,归纳和讨论了国内外弹塑性反应谱的研究现状,阐述了现有一些弹塑性反应谱研究的不足,并指出研究的基于Park和Ang双参数损伤模型的弹塑性反应谱,能够综合考虑了结构最大位移反应和结构累积滞回耗能的耦合作用,使弹塑性反应谱的研究进一步深化;最后,指出了弹塑性反应谱在基于性能抗震评估中的应用,但要将弹塑性反应谱应用于抗震设计规范中还存在诸多困难。 相似文献
5.
《建筑结构学报》2017,(1)
在加速度反应谱与峰值速度不变的条件下,研究输入地震动峰值位移对单自由度体系动力反应、尤其是弹塑性动力反应的影响。利用在时域内叠加窄带时程的方法合成加速度反应谱和峰值速度相同而峰值位移相差1倍的两组人工地震动时程,按照GB 50011—2010《建筑抗震设计规范》的要求,将合成的输入地震动采用不同设防烈度多遇地震的峰值加速度标定,进行体系的弹性分析。结果显示,输入地震动峰值位移的变化对弹性动力反应基本无影响。将输入地震动采用相应烈度罕遇地震的峰值加速度标定,并以上述多遇地震作用下弹性最大位移反应作为罕遇地震作用下结构弹塑性分析的屈服位移,进而分析输入地震动峰值位移变化对弹塑性动力反应的影响规律。结果表明:峰值位移的增大将会明显增大中长周期结构弹塑性位移反应和速度反应,这种放大效应对位移反应尤为显著,其规律在不同设防烈度区具有一致性,即随着设防烈度的提高,输入地震动峰值位移的增大引起的大部分中长周期结构弹塑性位移及速度反应的放大效应减小。因此,在进行结构动力分析时,应充分考虑输入地震动峰值位移变化对计算结果的影响。 相似文献
6.
本文首先对国外现有几种结构弹塑性地震位移反应简化计算方法进行了比较与评述。然后通过算例分析,指出在多层剪切型结构的质量、刚度和屈服抗剪强度三个因素中,屈服强度及其沿高的分布是影响结构弹塑性层间位移的关键因素。在此基础上,通过统计分析,提出了多层均匀结构弹塑性最大层间位移与相应的弹性层间位移之间关系的简化公式。最后对结构的不均匀性可能造成的层间塑性变形集中及屈服强度沿高度的标准分布进行了一些讨论。 相似文献
7.
中高层混合结构弹塑性变形简化计算方法 总被引:1,自引:1,他引:0
将中高层混合结构简化为一竖向弯曲梁与一竖向剪切梁,考虑其协同工作,并考虑重力二阶效应的影响。分别采用弹性设计反应谱和增大系数方法计算结构弹性位移和弹塑性位移,进而计算结构在多遇地震下的弹性位移以及罕遇地震下的弹塑性位移。对一20层混合结构算例进行分析,结果显示:采用该方法计算所得地震作用下的横向变形同"精确"分析方法所得的结果很相近,满足结构初步设计阶段要求。 相似文献
8.
采用反向加载时刚度退化的修正克拉夫(Modified-Clough,MC)滞回模型,计算单自由度体系(SDOF)在4类场地下共370条地震波输入后的弹塑性动力时程响应.利用屈服位移在结构设计过程中的稳定性,提出了可描述屈服位移和屈服强度系数之间关系,且辐线周期用地震波特征周期标准化的屈服点谱YPS(Yielding Point Spectra).以屈服位移作为基本设计参数的YPS谱是一种等延性反应谱,其不但可以直接用于抗震结构的弹塑性设计,还可以用于验算结构在地震作用下的最大弹塑性位移反应. 相似文献
9.
10.
11.
结构的弹塑性位移比及R-μ-T关系的分析 总被引:1,自引:0,他引:1
在估计已知强度或延性的现有结构在不同地震动强度下的最大地震弹塑性反应时,弹塑性位移比谱和等延性强度谱是十分准确有效的.通过对342条地震记录进行单自由度体系的弹塑性时程分析,研究了三个特征周期设计分组在不同延性系数下的弹塑性位移比谱特性以及等延性强度谱的特性,通过非线性回归分析建立了等延性位移比谱和等延性强度谱,给出了回归计算公式.研究表明:(1)弹塑性位移比谱在周期为0~1.0 s时谱值随周期的增加急剧下降,下降区间的终点与地震分组有关,之后谱曲线转入平缓,且延性系数对平缓段的曲线影响较小;(2)延性系数μ>1时,等延性强度谱在周期区间为0~1.0 s时谱值随周期的增加急剧增长,上升区间的终点与地震分组有关,之后谱曲线增长较为平缓,等延性强度谱随延性系数增加而增加;(3)等延性位移比谱和等延性强度谱的回归计算公式能反映延性位移比和折减系数的统计规律,可应用于实际工程. 相似文献
12.
13.
14.
15.
采用现有方法分析索网结构非线性动力反应时,仅能对矩形平面索网结构建立等效单自由度(ESDF)模型,地震作用下,此类结构的响应只能采用时程法进行计算。基于结构整体刚度参数的概念,结合模态推覆分析方法,建立了任意形状索网结构的非线性ESDF模型,该模型刚度特性与Duffing系统相同。采用能量平衡法,导出了索网结构非线性ESDF体系的等效线性刚度ke与位移反应d的关系;结合ESDF体系的等效质量,将加速度-周期(a-T)格式的设计反应谱变换为刚度-位移(k-d)格式;与ke-d关系式联立求解得出ESDF体系的非线性地震反应。该方法在线性设计反应谱的基础上,合理考虑了索网结构的非线性刚化效应。数值算例表明,相对于线性振型叠加反应谱法,该方法具有更好的适用性。 相似文献
16.
Hossein Kayhani Alireza Azarbakht Mohsen Ghafory‐Ashtiany 《The Structural Design of Tall and Special Buildings》2013,22(17):1279-1295
A methodology based on the progressive incremental dynamic analysis has been introduced in this paper to estimate the structural response and the corresponding annual probability of failure. The proposed methodology employs the genetic algorithm optimisation technique and an equivalent single‐degree‐of‐freedom system corresponding to the first‐mode period of a considered structure. The proposed methodology can significantly reduce the number of ground motion records needed for estimating the annual probability of failure. The numerical results indicate that the proposed method can effectively reduce the computational effort needed for computation of probability of failure for the first‐mode dominated structures, which is advantageous as the structure becomes larger. A relatively huge set of single‐degree‐of‐freedom systems as well as three multi‐degree‐of‐freedom systems including 3, 8 and 12 storeyed reinforced concrete structures was taken into account to test the proposed methodology. It has been shown that the probability of failure can be estimated within ±15% error with 95% confidence. The proposed method can speed up the decision‐making process in the probability‐based seismic performance assessment of structures, and it also incorporates the randomness of strong ground motions explicitly. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
17.
Estimation of inelastic displacement factor of soil‐shallow‐foundation MDOF systems incorporating higher modes effect 下载免费PDF全文
Abolfazl Gholamrezatabar Gholamreza Ghodrati Amiri Mohsen A. Shayanfar Behnoud Ganjavi 《The Structural Design of Tall and Special Buildings》2017,26(18)
This study attempts to investigate the higher‐mode effects on the constant‐ductility inelastic displacement factors of multi‐degree‐of‐freedom (MDOF) systems considering soil‐structure interaction. These factors were computed for 12,600 two‐dimensional superstructure models of shear buildings and their corresponding equivalent single‐degree‐of‐freedom (ESDOF) systems under 26 ground motions recorded on alluvium and soft soil. An intensive parametric study was carried out for a wide range of non‐dimensional parameters, which completely define the problem. The underlying soil is considered as a homogeneous half‐space based on the concept of cone model. The higher‐mode effects were then investigated through defining the ratio of inelastic displacement factor of MDOF system to that of the corresponding ESDOF one. The influence of soil‐structure interaction key parameters, fundamental period, ductility ratio, the number of stories, and dispersion of the results are evaluated and discussed. Results indicate that as the base becomes very flexible, unlike to the fixed‐base systems, in which the defined ratios are greater than unity, using the inelastic displacement factors of ESDOF models for MDOF ones would result in a remarkable overestimation of maximum inter‐story displacement demand. A new expression is proposed to estimate the ratio of inelastic displacement factor of MDOF soil‐structure systems to that of SDOF counterpart. 相似文献
18.
19.
Lieping Ye Qianli Ma Zhiwei Miao Hong Guan Yan Zhuge 《The Structural Design of Tall and Special Buildings》2013,22(4):362-381
Elastoplastic and time‐dependent analysis of seismic structures has become a major analysis technique in popularly accepted performance‐based seismic design. However, the primary difficulty in using this technique is the lack of a unified criterion in the selection of various intensity indices of ground motions. Various earthquake factors influencing the elastoplastic response of seismic structures are highly sophisticated. Hence, it is vitally important to choose an appropriate and comprehensive earthquake intensity index to achieve an accurate correlation with the structural performance. In this study, a total of 30 earthquake intensity indices published in the literature are reviewed and are evaluated through correlation analysis based on 60 ground motion records. Examined herein is the correlation between existing earthquake intensity indices and the seismic responses of elastoplastic single degree‐of‐freedom and multi degree‐of‐freedom systems. The characteristics and applicability of such indices are also discussed in some detail, based on which appropriate earthquake intensity indices are recommended. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献