首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
The damage distribution in Adra town (south‐eastern Spain) during the 1993 and 1994 Adra earthquakes (5.0 magnitude), that reached a maximum intensity degree of VII (European Macroseismic Scale (EMS scale)), was concentrated mainly in the south‐east zone of the town and the most relevant damage occurred in reinforced concrete (RC) buildings with four or five storeys. In order to evaluate the influence of ground condition on RC building behaviour, geological, geomorphological and geophysical surveys were carried out, and a detailed map of ground surface structure was obtained. Short‐period microtremor observations were performed in 160 sites on a 100m × 100m dimension grid and Nakamura's method was applied in order to determine a distribution map of soil predominant periods. Shorter predominant periods (0.1–0.3 s) were found in mountainous and neighbouring zones and larger periods (greater than 0.5 s) in thicker Holocene alluvial fans. A relationship T = (0.049 ± 0.001)N, where T is the natural period of swaying motion and N is the number of storeys, has been empirically obtained by using microtremor measurements at the top of 38 RC buildings (ranging from 2 to 9 storeys). 1‐D simulation of strong motion on different soil conditions and for several typical RC buildings were computed, using the acceleration record in Adra town of the 1993 earthquake. It is noteworthy that all the aforementioned results show the influence of site effects in the degree and distribution of observed building damage. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

2.
2017年5月11日新疆塔什库尔干5.5级地震给震区建筑结构造成了不同程度破坏。选择震区钢筋混凝土(RC)框架结构、砖混结构以及土石木结构等3类典型建筑结构,介绍了各类建筑结构地震破坏特点,分析了震害特征与破坏机理。结果表明:RC框架结构在地震中表现出了优异的抗震性能,即使在震中区,破坏也仅仅表现为非结构性破坏,如填充墙开裂和吊顶脱落等;砖混结构绝大多数抗震性能优良,仅震中区的少数建筑物发生了承重墙墙体开裂情况;土石木结构房屋抗震性能最差,地震破坏最为严重,是导致该次地震人员伤亡主要原因。建议地震高烈度设防区房屋建筑应采用抗震性能较好的RC框架结构和砖混结构,而抗震性能差的土石木建筑房屋应尽量避免继续建设和使用。结果可供类似地区房屋建设和建筑结构抗震设计等工作参考。  相似文献   

3.
A retrofitting technology using precast steel reinforced concrete (PSRC) panels is developed to improve the seismic performance of old masonry buildings. The PSRC panels are built up as an external PSRC wall system surrounding the existing masonry building. The PSRC walls are well connected to the existing masonry building, which provides enough confinement to effectively improve the ductility, strength, and stiffenss of old masonry structures. The PSRC panels are prefabricated in a factory, significantly reducing the situ work and associated construction time. To demonstrate the feasibility and mechanical effectivenss of the proposed retrofitting system, a full-scale five-story specimen was constructed. The retrofitting process was completed within five weeks with very limited indoor operation. The specimen was then tested in the lateral direction, which could potentially suffer sigifnicant damage in a large earthquake. The technical feasibility, construction workability, and seismic performance were thoroughly demonstrated by a full-scale specimen construction and pseudo-dynamic tests.  相似文献   

4.
An earthquake with a magnitude of 5.7 $(\text{ M}_{\mathrm{L}})$ has struck Simav, Kutahya located in the western part of Turkey on May 19, 2011. The ground motion caused observable damage within 25 km radius from the epicenter. Although the earthquake is moderate, its effects on the structures are serious. This paper presents the observations on seismic damages of reinforced concrete (RC) and masonry structures. Common reasons of damage in RC buildings are: low quality of concrete, detailing mistakes of reinforcement, short column, pounding, overhangs and misconstructed gable and outer infill wall parts. Interesting cases related to these deficiencies are reported. Damages in the masonry buildings are due to lack of connection between orthogonal walls and unsuitable location and dimension of openings. The damages at structures are more noticeable at regions with unfavorable soil conditions like plain regions or foothills. However, on stiffer soils at hilly sides, the damages seem to be more limited and masonry structures are observed to be less affected compared to the RC ones. The damages in RC buildings found to be increasing with story number for light damage states. However, for heavier damage states, 4–5 story buildings are observed to be the most damaged.  相似文献   

5.
汶川8.0级地震房屋建筑震害特征   总被引:3,自引:2,他引:1  
尽管在汶川大地震中大量房屋建筑遭受了严重破坏,然而,不同类型的房屋建筑所表现出的反应特征各不相同。本文在地震灾区震害现场调查所收集的大量资料的基础上,着重对几类主要房屋建筑,如砖木房屋、多层砌体房屋、钢筋混凝土房屋等在强烈地震作用下的地震反应及震害进行了总结和分析,以期从中得到一些有益的认识,为灾区恢复重建提供科学依据。  相似文献   

6.
基于2013年4月20日四川芦山MS7.0地震灾区的房屋建筑震害调查资料, 初步分析了这次地震中建筑结构的震害特征. 结合典型建筑结构震害案例, 从抗震概念设计和抗震构造措施的角度对震害机理进行了探讨, 总结了结构抗震设计方面的经验和教训并给出了相关的建议. 分析表明, 农村自建的砖木和土木结构房屋的抗震能力普遍较差; 砖混结构和砌体-框架混合结构的抗震性能需要严格的抗震构造措施给予保证, 包括合理设置钢筋混凝土构造柱和圈梁, 合理设置承重墙的数量以及承重墙上开洞的数量和位置; 由于鞭梢效应造成的突出屋顶的楼梯间和加层的破坏需引起重视.   相似文献   

7.
This study focuses on the seismic safety evaluation of masonry buildings in Turkey for in‐plane failure modes using fragility curves. Masonry buildings are classified and a set of fragility curves are generated for each class. The major structural parameters in the classification of masonry buildings are considered as the number of stories, load‐bearing wall material, regularity in plan and the arrangement of walls (required length, openings in walls, etc.), in accordance with the observations from previous earthquakes and field databases. The fragility curves are generated by using time history (for demand) and pushover (for capacity) analyses. From the generated sets of fragility curves, it is observed that the damage state probabilities are significantly influenced from the number of stories and wall material strength. In the second stage of the study, the generated fragility curves are employed to estimate the damage of masonry buildings in Dinar after the 1995 earthquake. The estimated damage by fragility information is compared with the inspected visual damage as assessed from the Damage Evaluation Form. For the quantification of fragility‐based damage, a single‐valued index, named as ‘vulnerability score’ (VS), is proposed. There seems to be a fair agreement between the two damage measures. In addition to this, decisions regarding the repair or demolition of masonry buildings in Dinar due to visual damage inspection are on comparable grounds with the relative measure obtained from VS of the same buildings. Hence, the fragility‐based procedure can provide an alternative for the seismic safety evaluation of masonry buildings in Turkey. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

8.
On 3 August 2014, the Ludian earthquake struck northwest Yunnan Province with a surface wave magnitude of 6.5. This moderate earthquake unexpectedly caused high fatalities and great economic loss. Four strong motion stations were located in the areas with intensity V, VI, VII and IX, near the epicentre. The characteristics of the ground motion are discussed herein, including 1) ground motion was strong at a period of less than 1.4 s, which covered the natural vibration period of a large number of structures; and 2) the release energy was concentrated geographically. Based on materials collected during emergency building inspections, the damage patterns of adobe, masonry, timber frame and reinforced concrete (RC) frame structures in areas with different intensities are summarised. Earthquake damage matrices of local buildings are also given for fragility evaluation and earthquake damage prediction. It is found that the collapse ratios of RC frame and confined masonry structures based on the new design code are significantly lower than non-seismic buildings. However, the RC frame structures still failed to achieve the ‘strong column, weak beam’ design target. Traditional timber frame structures with a light infill wall showed good aseismic performance.  相似文献   

9.
Experimental tests have shown that unreinforced masonry (URM) infill walls are affected by simultaneous loading in their in-plane and out-of-plane directions, but there have been few attempts to represent this interaction in nonlinear time history analysis of reinforced concrete (RC) buildings with URM infill walls. In this paper, a recently proposed macro-model that accounts for this interaction is applied to the seismic analysis of RC framed structures with URM infill walls representative of Mediterranean building stock and practices. Two RC framed structures that are representative of low and mid-rise residential buildings are analysed with a suite of a bidirectional ground motions, scaled to three different intensities. During the analyses, the in-plane/out-of-plane interaction is monitored, showing that cracking of the infills occurs predominantly by in-plane actions, while failure occurs due to a combination of in-plane and out-of-plane displacements, with the out-of-plane component usually playing the dominant role. Along the frame height, the bottom storeys are generally the most damaged, especially where thin infill walls are used. These results are consistent with observations of damage to URM infill walls in similar buildings during recent earthquakes.  相似文献   

10.
Post-earthquake surveys indicate that losses come from non-structural damage more than from structural damage. Current performance-based design would prevent excessive non-structural damage as well, but the effectiveness of relevant code provisions has not been assessed in depth. This study investigates the drift-sensitive non-structural damage to reinforced concrete frame buildings complying with the European seismic code. Damage to non-structural unreinforced masonry infill walls in contact with the frame is quantified in terms of numerical fragility curves with the same quantities considered in the design: the peak ground acceleration measures the seismic intensity; the peak value of the interstorey drift ratio is the damage index. The methodology for the fragility computation is described in detail. Peculiar is the use of probabilistic parameters of the drift capacity coupled to the fuzziness in the damage state. The drift demand is estimated by member-by-member modelling of typical frame structures and non-linear time–history analyses under spectrum-compatible artificial accelerograms. The kind of the infills and their modelling, the number of storeys, the ground type, and the ductility class are covered. Modelling the infills results to be essential. Any code-compliant verification is on the safe side, but the margin appears to be inconsistent among the frames under consideration. Furthermore, there is one case where occupancy appears to be not ensured despite the code verification is satisfied. The effect of the number of storeys may be misrepresented. The ductility class may be unimportant, however the damage seems to be correlated with the likely strength.  相似文献   

11.
江苏高邮、宝应MS4.9级地震现场震害调查与破坏原因研究   总被引:1,自引:1,他引:0  
江苏高邮、宝应Ms4.9级地震在极震区造成了数10间农村民居不同程度和不同方式的破坏,出现人员伤亡。震后对地震灾害现场进行震害调查与破坏原因研究,典型的震害特征包括砖砌体、砖木和砖混结构房屋局部倾倒、墙体贯通开裂、房顶瓦片掀翻和烟囱倒塌等。农村民居遭到破坏的主要因素包括:选址不当、施工质量较差、砂浆强度不够、缺少圈梁和构造柱等。同时,分析了竖向地震作用和鞭梢效应等地震效应,讨论了砖砌体和砖混结构抗震设计的加固方法和改善抗震性能的构造措施等,为农村民居的抗震设防和减轻震害损失等提供参考。  相似文献   

12.
组合墙结构房屋抗震性能的振动台试验研究   总被引:1,自引:0,他引:1  
通过三个组合墙模型房屋的振动台试验,分析了组合墙结构体系房屋的动力性能和抗震能力,比较了底一层和底两层框架组合墙房屋和普通组合墙房屋的抗震性能。结果表明,八层组合墙房屋的抗震能力远远超过设计能力,可用于八度地区,底框架组合墙房屋的抗震性能优于普通组合墙房屋,底两层框架组合墙房屋也优于底一层框架组合墙房屋。  相似文献   

13.
14.
The present paper aims to contribute to the knowledge concerning the seismic assessment of load bearing masonry buildings with reinforced concrete slabs. The final goal of the present research was to propose a simple, yet accurate, methodology to assess the seismic safety of existing masonry buildings. The methodology here presented was based on the so-called ICIST/ACSS methodology with major improvements such as the extension to load bearing masonry wall buildings and the consideration of the effects of one of the most common strengthening solutions for masonry walls, here referred to as reinforced plastering mortar, as well as the possibility of considering four levels of increasing refinement: global, by alignment, by wall panel and by wall element. An extended research was performed on the existing methodologies to evaluate the seismic structural risk of load bearing masonry buildings, briefly describing methodologies similar to the one proposed, namely all of those that have in common the fact that they are based in the physical comparison between the resisting and acting shear forces at all storeys and along the two orthogonal horizontal directions. A case study is presented to check the applicability of the proposed methodology. The case study showed that the proposed methodology is relatively simple to apply and has a sufficiently good accuracy when compared with alternative methodologies. The degree of refinement of the analysis (global, by alignment, by wall panel and by wall element) must be taken into consideration and successively more complex analyses may be required when the results of simpler analyses are inconclusive.  相似文献   

15.
Non‐ductile reinforced concrete buildings represent a prevalent construction type found in many parts of the world. Due to the seismic vulnerability of such buildings, in areas of high seismic activity non‐ductile reinforced concrete buildings pose a significant threat to the safety of the occupants and damage to such structures can result in large financial losses. This paper introduces advanced analytical models that can be used to simulate the nonlinear dynamic response of these structural systems, including collapse. The state‐of‐the‐art loss simulation procedure developed for new buildings is extended to estimate the expected losses of existing non‐ductile concrete buildings considering their vulnerability to collapse. Three criteria for collapse, namely first component failure, side‐sway collapse, and gravity‐load collapse, are considered in determining the probability of collapse and the assessment of financial losses. A detailed example is presented using a seven‐story non‐ductile reinforced concrete frame building located in the Los Angeles, California. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

16.
An Ms ~ 6 earthquake, originating at a normal fault directly underneath the town of Kalamata, caused substantial structural damage to reinforced-concrete and masonry buildings, to contemporary as well as centuries-old churches, and to a major harbour quaywall. Two accelerograms were recorded on stiff alluvial deposits. The seismologic and engineering facts of the earthquake are presented in the first half of the paper. Particular attention is paid to the non-uniform pattern of damage distribution, at both regional and local scale. The second half of the paper investigates the possible role of the ‘local soil conditions’ and of the ‘mechanics of the source’ in the observed pattern of damage and in the amplitude and frequency composition of the two records. To this end, numerical modelling of site-specific motions is attempted using state-of-practice methods, and utilizing the results of an extensive geotechnical exploration programme. It is concluded that substantial evidence does exist indicating that both soil and source effects have contributed to the non-uniform spatial distribution of damage. The effect of through-soil ‘filtering’ of the seismic waves appears most evident in the coastal neighbourhoods of the town, where the underlying loose saturated silty sands in the over-50 m-deep soil deposit may have played a beneficial role in weakening the ground-surface shaking; the structural damage in these areas was insignificant. Qualitative arguments are also put forward for explaining some aspects of the observed pattern of damage in terms of fault orientation and ‘directivity’ effects.  相似文献   

17.
The methodologies used in Greece for estimating direct losses in both reinforced concrete (R/C) and masonry buildings (also including monuments) are summarised, the critical issue of data collection is addressed, and practical solutions that have been tried are discussed. The development of a seismic risk scenario for contemporary and historical buildings in Thessaloniki is then presented and some key results are given, including the expected geographical distribution of building damage (due to the scenario earthquake) in the municipality of Thessaloniki; damage is described both in structural and in economic terms.  相似文献   

18.
提出了带竖向构造钢筋再生混凝土砖砌体结构,进行了2个两层再生混凝土砖砌体房屋结构1/2缩尺模型的模拟地震振动台试验研究,2个结构模型的墙体厚度均为120 mm,一层设有门洞和窗洞,二层设有窗洞。2个模型中,1个为带竖向构造钢筋再生混凝土砖砌体房屋,1个为普通无竖向构造钢筋再生混凝土砖砌体房屋。试验中输入El Centro地震动,测试分析了台面加速度反应、一层和二层顶板加速度反应、结构层间位移反应以及各阶段结构损伤与破坏特征等。研究表明:带竖向构造钢筋再生混凝土砖砌体房屋比普通再生混凝土砖砌体房屋的破坏程度轻,墙体裂缝位置相对错动小,抗震性能显著提高;带竖向构造钢筋再生混凝土砖砌体房屋可用于地震区村镇建筑。  相似文献   

19.
This study proposes a procedure for identifying spectral response curves for earthquake‐damaged areas in developing countries without seismic records. An earthquake‐damaged reinforced concrete building located in Padang, Indonesia was selected to illustrate the identification of the maximum seismic response during the 2009 West Sumatra earthquake. This paper summarizes the damage incurred by the building; the majority of the damage was observed in the third story in the span direction. The damage was quantitatively evaluated using the damage index R according to the Japanese guidelines for post‐earthquake damage evaluation. The damage index was also applied to the proposed spectral response identification method. The seismic performance of the building was evaluated by a nonlinear static analysis. The analytical results reproduced a drift concentration in the third story. The R‐index decreased with an increase in the story drift, which provided an estimation of the maximum response of the building during the earthquake. The estimation was verified via an earthquake response analysis of the building using ground acceleration data, which were simulated based on acceleration records of engineering bedrock that considered site amplification. The maximum response estimated by the R‐index was consistent with the maximum response obtained from the earthquake response analysis. Therefore, the proposed method enables the construction of spectral response curves by integrating the identification results for the maximum responses in a number of earthquake‐damaged buildings despite a lack of seismic records. Copyright © 2016 The Authors. Earthquake Engineering & Structural Dynamics published by John Wiley & Sons Ltd.  相似文献   

20.
青海省共和地区位于柴达木—阿尔金地震带内,具备发生中强地震的构造背景,近年来该地区地震活动频繁,农村地区受经济和技术等条件的限制,造成了巨大的人员伤亡和经济损失。为深入了解共和地区农村民居结构特征与抗震性能现状,开展实地调查,基于历史震害资料,总结区域内典型农村民居震害特点,并进行震害预测,得到不同地震烈度下农村民居不同的破坏结果。结果表明:青海省共和地区农村民居中的砖混结构和砖木结构房屋数量约占48%、47%,其中约68%砖混结构房屋未设置构造柱和圈梁等抗震设防措施;该地区主要农村民居基本达到Ⅶ度抗震设防要求,仅部分建造年代久的土木结构房屋破坏严重;地震烈度为Ⅷ度时,大部分房屋以中等破坏和严重破坏为主;地震烈度为Ⅸ、Ⅹ度时,农村民居将发生大范围严重破坏,甚至毁坏。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号