共查询到18条相似文献，搜索用时 140 毫秒
1.
地震破坏状态概率分析是抗震结构最优设防水平决策与全寿命优化设计的关键问题之一,作者们曾根据"三水准"设防原则和地震烈度的危险性分析结果提出了二种实用分析方法.本文建立了结构破坏状态概率分析的地震易损性理论基础,提出了极限状态地震易损性和破坏状态地震易损性的概念.从地震易损性理论的角度,对二种地震破坏状态概率简化分析方法进行了深入分析,指出第1种方法是一种考虑结构宏观抗震能力不确定性的半理论半经验易损性分析方法,而第2种方法则是一种不考虑结构宏观抗震能力不确定性的简化易损性分析方法,根据地震破坏状态概率的计算结果对二种方法进行了对比分析,并提出了相关的建议. 相似文献
2.
以汶川地震为研究背景,针对震后典型钢筋混凝土框架结构进行地震易损性研究。基于Cornell理论框架结合汶川地质资料,拟合出考虑场地特点的地震危险性模型,同时定义损伤水平状态及限值指标,以概率解析易损性研究方法为基础,运用考虑地震动参数的解析易损性评估方法绘制汶川地区钢筋混凝土框架建筑的地震易损性曲线。研究结果表明:考虑地震动参数的概率解析易损性研究方法是一种有效的地震易损性评估方法;以PGA作为地震强度输入指标的结构反应,随自振周期的增大体系最大响应的相关性降低,结构各个损伤状态的失效概率均随之增大。 相似文献
3.
以某典型的12层钢筋混凝土框架结构作为研究对象,研究基于非线性动力时程分析和地震动参数的RC框架结构易损性分析方法。首先采用静力pushover分析判定结构薄弱层,并确定结构性能(capacity)参数;然后应用非线性动力时程分析估计结构地震反应,研究以峰值加速度和基本周期加速度反应谱作为地震动参数结构反应的不确定性,并进一步分析结构地震需求(demand)参数与地震动参数的关系;在此基础上,分别建立该结构基于峰值加速度和加速度反应谱的易损性曲线,通过考虑场地条件对地震动特性的影响,研究场地条件对结构易损性的影响,结果表明不同场地条件下的结构易损性曲线有一定差异。应用本文方法,根据新一代地震区划图或地震安全性评价确定的地震动参数,可以直接估计结构在未来地震中出现不同破坏的概率,这在结构的抗震性能评估和地震损失预测中有一定意义。 相似文献
4.
基于概率估计方法的立式储罐地震易损性研究 总被引：1，自引：1，他引：0
结合储罐的震害资料和震害特点,提出了基于概率估计方法的立式储罐地震易损性研究.考虑了结构的随机性及荷载作用的随机性,给出了各随机变量的概率分布模型及给定烈度下地震发生的概率.从可靠度指标的几何意义入手,提出了储罐的地震易损性计算方法.通过2×103m3和5×104m32种高矮罐的地震易损性研究,结果表明:通过概率方法和绘制地震易损性曲线的方式,更能直观的给出储罐各失效模式的地震易损性.储罐的地震易损性与地震烈度、高径比的关系很大,地震易损性随着地震烈度的增大逐渐增大;与2×103m3储罐相比,5×104m3储罐各失效模式地震易损性明显较小;从多种失效模式进行储罐地震易损性研究更具有科学性. 相似文献
5.
《地震工程与工程振动》2021,41(2)
描述地震作用与工程破坏之间关系的易损性曲线及其概率分布对于地震灾害损失的可靠评估至关重要。以对数正态分布为主体的现行易损性概率分布模型无法很好地描述完好无损和完全破坏这2种边界条件。文中基于新西兰近40万栋房屋的历史震害信息,确认了这2种边界条件的存在,并对各种给定地震动水平下结构的损失分布进行了研究,提出了考虑上述2种边界条件的易损性混合概率分布模型,即首先单独考虑完好无损和完全破坏2种边界情况,然后再利用分布函数拟合其他的地震损失分布。通过对混合概率分布模型的损失分布与实际损失分布进行比较,验证了文中所提模型的有效性,可以用于未来分析地震损失的不确定性分布。 相似文献
6.
用贝塔分布函数对给定烈度下结构各个破坏等级的概率分布进行了破坏比概率密度的拟合,以地震动峰值作为地震动参数,根据烈度和加速度峰值的对应关系以对数插值方式计算了在任意一个峰值加速度下结构破坏比的倍塔概率密度分布及各个破坏等级的概率,从而使结构易损性的表达方式由烈度-震害等级构成的二维阶跃性易损性矩阵转化为由地震动参数-破坏比概率密度函数或地震动参数-各破坏等级的概率来表达的方式.试算结果表明,这种转化方法是可行的.本文为震害预测和地震经济损失估计提供参考. 相似文献
7.
从板式橡胶支座及混凝土挡块抗震设计角度，以一座典型的3跨预应力混凝土连续梁桥为例，结合概率地震需求分析及桥墩、支座等抗震关键构件极限破坏状态，建立不同支座及挡块分析模型的中小跨径梁桥地震易损性曲线，研究考虑支座滑移效应及挡块破坏的中小跨径梁桥的易损性特征。研究结果表明:不考虑橡胶支座的滑移效应及混凝土挡块破坏，桥墩地震破坏概率明显增大，且会低估支座破坏概率；桥梁系统易损性受支座破坏状态的影响显著，需设置合理的限位装置；在中小跨径梁桥地震易损性分析中，考虑支座的滑移效应及混凝土挡块的破坏十分必要。 相似文献
8.
砌体结构的震害现象表明楼层侧向刚度不均匀分布是造成其破坏的重要原因之一。本文开展楼层侧向刚度变化对结构易损性的影响分析。以3层和6层砌体结构为例，采用等效多自由度层间剪切模型，基于非线性动力时程分析，定量研究了竖向刚度不规则性对砌体结构易损性的影响。以结构最大层间位移角为地震反应参数，借助增量动力分析及回归拟合方法，建立了基于峰值加速度的结构易损性曲线。通过改变楼层的侧向刚度值来模拟薄弱层，研究了楼层刚度变化对结构不同破坏状态超越概率的影响。通过改变底层与二层的侧向刚度比，分析了底部刚度突变对结构不同破坏状态超越概率分布的影响。研究表明:与规则结构相比，当刚度突变位于结构底层时，在地震作用下结构易损性相对较高；随着底层与二层的侧向刚度比从0.5增大至1.2，结构易损性逐渐降低。当刚度比为1.5时，结构薄弱层由底层转移至二层，结构整体易损性增加；当底层与二层侧向刚度比小于1时，结构倒塌易损性要显著高于规则结构。 相似文献
9.
为确定桩土作用对一座位于Ⅲ类场地上的110m三跨连续梁桥地震易损性曲线和震后通行能力的影响,首先建立墩底固结和考虑桩土作用2种有限元模型,选取50条实测的、符合工程场地条件的不同强度地震波作为输入,分别以桥墩墩顶和支座最大位移为目标响应,计算得到转角延性比和支座剪应变值,进而构建桥墩和支座的易损性曲线;然后通过宽界限法建立桥梁系统的地震易损性曲线,提出新的平均损伤水平值计算公式并结合易损性曲线评估该连续梁桥的震后通行能力。分析结果表明,同一地震强度下考虑桩土作用时的桥墩位移峰值比墩底固结情况大,更符合实际情况;对于桥梁构件易损性曲线而言,考虑桩土作用时支座破坏超越概率最大,但与墩底固结情况相比相差不大;采用桥梁系统地震易损性曲线评价桥梁交通流量变化更加合理,固结模型的震后交通流量评估Ⅲ类场地情况时不可忽略桩土作用对桥梁地震易损性的影响。 相似文献
10.
桥梁作为交通中不可或缺的一部分，对其地震易损性进行研究具有现实意义。针对当前桥梁地震易损性分析方法存在准确性待提升的问题，提出基于模糊评定的钢筋混凝土桥梁地震易损性评估模型。以桥梁结构层次、材料层次及边界层几方面为主对桥梁评估过程中的不确定性参数进行分析。以分析结果为依据，考虑到桥梁损失是一个比较模糊的概念，引入模糊数学中的模糊评定方法对桥梁地震易损性进行评估。融合位移下桥梁支座损伤分析、能量下桥墩损伤分析、周期下桥梁结构整体损伤分析，构建可以反映钢筋混凝土桥梁由局部到整体的多层次模糊易损性评估模型。通过实验对所建模型进行验证，结果显示：在纵向只发生轻微破坏，且轻微破坏的概率较小，基本处于完好状态。而在横向，发生轻微破坏的概率较大，甚至还可能发生中等破坏。在地震作用下，桥梁破坏也基本以轻微破坏和中等破坏为主，严重破坏的概率很小。 相似文献
11.
Introduction The estimation of damage probability distribution among different damage states of rein-forced concrete buildings is a key component of earthquake loss estimation for modern city or a group of cities. With the development of city, the reinforced concrete buildings are major compo-nent parts of modern cities. Vulnerability estimates for these kinds of buildings are of importance to those responsible for civil protection, relief, and emergency services to enable adequate contin-genc… 相似文献
12.
Building damage scenarios based on exploitation of Housner intensity derived from finite faults ground motion simulations 总被引：2，自引：2，他引：0
Leonardo Chiauzzi Angelo Masi Marco Mucciarelli Marco Vona Francesca Pacor Giovanna Cultrera Frantisek Gallovič Antonio Emolo 《Bulletin of Earthquake Engineering》2012,10(2):517-545
In this paper earthquake damage scenarios for residential buildings (about 4200 units) in Potenza (Southern Italy) have been
estimated adopting a novel probabilistic approach that involves complex source models, site effects, building vulnerability
assessment and damage estimation through Damage Probability Matrices. Several causative faults of single seismic events, with
magnitude up to 7, are known to be close to the town. A seismic hazard approach based on finite faults ground motion simulation
techniques has been used to identify the sources producing the maximum expected ground motion at Potenza and to generate a
set of ground motion time histories to be adopted for building damage scenarios. Additionally, site effects, evaluated in
a previous work through amplification factors of Housner intensity, have been combined with the bedrock values provided by
hazard assessment. Furthermore, a new relationship between Housner and EMS-98 macroseismic intensity has been developed. This
relationship has been used to convert the probability mass functions of Housner intensity obtained from synthetic seismograms
amplified by the site effects coefficients into probability mass function of EMS-98 intensity. Finally, the Damage Probability
Matrices have been applied to estimate the damage levels of the residential buildings located in the urban area of Potenza.
The proposed methodology returns the full probabilistic distribution of expected damage, thus avoiding average damage index
or uncertainties expressed in term of dispersion indexes. 相似文献
13.
14.
The seismic vulnerability index(Kg) is a parameter that depends on the dynamic properties of soil. With this parameter, it is possible to evaluate the vulnerability of a point-based site under strong ground motion. Since it is related to the natural vibration period and amplification factor, the parameter can be calculated for both soil and structure. In this study, HVSR microtremor measurements are recorded at more than 200 points in the Van region to generate a seismic vulnerability index map. After generating the map, it is determined that the hazard potential and seismic vulnerability index is high at the sites close to Van Lake and at the densely populated city center. Damage information of the buildings investigated after the 2011 Van earthquakes(Mw = 7.1) are placed on the seismic vulnerability index map and it is realized that there may be a correlation between the damage and the seismic vulnerability index. There is a high correlation, approximately 80 percent, between the damage rate map based on the damaged building data and the K_g values. In addition, vulnerability indexes of buildings are calculated and the effect of local soil conditions and building properties on the damage levels are determined. From the results of this study and the site observations after the 2011 Van earthquakes, it is found that structural damage is not only structure-dependent but is also related to the dynamic behavior of soil layers and local soil conditions. 相似文献
15.
—?The problem of accounting for local soil effect on earthquake ground motion is especially urgent when assessing seismic hazard – recent needs of earthquake engineering require local site effects to be included into hazard maps. However, most recent works do not consider the variety of soil conditions or are performed for generalized site categories, such as “hard rock,”“soft soil” or “alluvium.” A technique of seismic hazard calculations on the basis of the Fourier Amplitude Spectra recently developed by the authors allows us to create hazard maps involving the influence of local soil conditions using soil/bedrock spectral ratios. Probabilistic microzoning maps may be constructed showing macroseismic intensity, peak ground acceleration, response and design spectra for various return periods (probability of exceedance), that allow optimization of engineering decisions. An application of this approach is presented which focused on the probabilistic microzoning of the Tashkent City. 相似文献
16.
Influence of spatial correlation of strong ground motion on uncertainty in earthquake loss estimation 总被引：1，自引：0，他引：1
In addition to the mean values of possible loss during an earthquake, parameters of the probability distribution function for the loss to a portfolio (e.g. fractiles and standard deviation) are very important. Recent studies have shown that the proper treatment of ground‐motion variability and, particularly, the correlation of ground motion are essential for the estimation of the seismic hazard, damage and loss for distributed portfolios. In this study, we compared the effects of variations in the between‐earthquake correlation and in the site‐to‐site correlation on seismic loss and damage estimations for the extended objects (hypothetical portfolio) and critical elements (e.g. bridges) of a network. A scenario earthquake approach and a portfolio containing a set of hypothetical building and bridges were used for the purpose. We showed that the relative influences of the types of correlation on characteristics of loss distribution and the probability of damage are not equal. In some cases, when the median values of loss distribution or the probability that at least one critical element of a lifeline will be damaged are considered and when the spatial correlation of ground motion is used, the possible variations in the between‐earthquake correlation may be neglected. The shape of the site‐to‐site correlation function (i.e. the rate of decrease of the coefficient of spatial correlation with separation distance) seems also to be important when modelling spatially correlated ground‐motion fields. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
17.
砌体建筑群在地震中往往破坏严重损失巨大，合理评估地震作用对不同种类砌体结构造成破坏的风险变得至关重要。传统基于后验概率的地震危险性分析方法忽略了砌体建筑个体差异性的影响，未深入考虑多种震害因子的耦合作用。本文以华南地区砌体建筑群为例，开发了一种集成概率方法来对城市砌体结构的破坏风险进行建模，考虑建筑年代、层数、使用用途和墙厚四类震害因子的耦合影响，采用(Kolmogorov-Smirnov)K-S检验，在设定地震动参数下选取Gaussian分布、Log-Normal分布、Gumbel分布和Beta分布四种概率分布对该地区砌体建筑物的破坏状态概率分布参数进行拟合。通过均方根误差(Root Mean Square Error)RMSE进行拟合优度评价，最终建立基于Gaussian分布和Log-Normal分布的砌体建筑物破坏联合概率模型。最后，以华南地区三个城市典型砌体建筑物为例进行实例对比验证，将基于本文建立的建筑破坏概率模型推算出的砌体建筑群震害矩阵与基于单体结构分析得到的震害矩阵进行对比，与理论值最大偏差为0.033 3。研究表明：本文构建的集成概率方法能够获得更加合理的城市砌体建筑... 相似文献
18.
工程场地的设计地震动参数,目前多用概率地震危险性分析的方法给出。场地的地震基本烈度以设计基准期T=50年、加速度超越概率P=0.1的标准确定。本文根据广东省数地地震危险性分析结果结合我国常见的砖混结构的地震动参数的优化决策,认为上述标准宜取为T=50年、P=0.05—0.1。 相似文献