5·12汶川地震绵阳市区房屋震害统计与分析

历次大地震的经验总结是推动建筑抗震技术发展的重要途径。通过绵阳市区房屋在汶川大地震后的震害应急评估和调查,对市区各类房屋结构的震害进行了统计,总结分析各类房屋的震害特征和经验教训。得到一些启示和建议：绵阳市区按现行抗震规范设计的房屋基本经受住了地震考验;不同的结构体系表现出的抗震性能差别较大;老旧房屋始终是抗震薄弱环节,应有选择地进行抗震鉴定加固,开展砖混结构墙体抗震防裂措施研究,采取措施有效减轻框架结构中填充墙等非结构构件的震害,开展楼梯抗震设计计算与构造措施的研究。     

大型公共建筑非结构构件抗震性能及#br# 韧性提升研究综述

大型公共建筑既是保障震后救灾及城市系统功能恢复的基础设施系统,又是地震灾害的重要承灾体。地震一旦发生,大型公共建筑中非结构构件会造成严重的地震灾害,影响建筑的使用功能、造成巨大的经济损失,甚至给人员疏散和安置带来潜在威胁。文章从理论分析、数值模拟及试验研究等3个方面系统总结非结构构件抗震性能分析方法的研究进展。以吊顶、幕墙及电梯为例阐述非结构构件的地震响应及破坏特征。探讨大型公共建筑中非结构构件抗震性能研究的新思路：结合材料科学、控制科学及交叉学科的发展,不断创新非结构构件的抗震性能分析方法;结合大数据和人工智能技术形成非结构构件震害评价方法和智能识别技术,为非结构构件的抗震韧性评估提供依据;发展非结构构件地震韧性提升技术,为大型公共建筑的安全运行提供技术保障。     

Probabilistic seismic risk assessment of hall buildings in Turkey

Steel space framed hall buildings are dedicated as shelters for people suffering from earthquakes. In general construction, steel space frames are built on reinforced concrete (R/C) frames or wall structures above the bottom side. For this reason, the bottom side has higher rigidity comparing with the upper side. In Turkey, where there is a very high earthquake risk, earthquake‐resistant steel space framed structures is an important issue. In this current research, hall buildings in Turkey, involving two different rigidity parts as R/C and steel, are taken into consideration regarding earthquake effect. In this study, three different hall structures were modeled with different elastic moduli for the analysis part. Nonlinear time history analyses were applied with 25 different earthquake data for performance estimation. After the time history analyses, probabilistic seismic assessment was carried out for the model buildings through fragility analyses. For each model, analysis results were evaluated and compared. As a result, the hall buildings were found to be vulnerable to damage during expected future earthquakes. Moreover, elastic moduli have significant effect on the structural response. Copyright © 2011 John Wiley & Sons, Ltd.     

Seismic vulnerability, behavior and design of tunnel form building structures

Multi-story reinforced concrete tunnel form buildings are one of the common structural types in regions prone to high seismic risk due to the buildings inherent earthquake resistance and ease of construction. Despite their good performance during earthquakes in 1999 in Turkey, and abundance of such structures scattered worldwide, current seismic codes and design provisions provide insufficient guidelines for their seismic design. As a compensatory measure, a series of modal and nonlinear static analyses are conducted by emphasizing the characteristic dynamic behavior of tunnel form buildings including impacts of wall-to-wall and wall-to-slab interaction and effects of torsion and wall-openings on the load transfer mechanism and seismic performance. A new formula for explicit determination of their fundamental period is developed in addition to a recommended response reduction factor and reinforcement detailing around shear-wall openings.     

Performance of Buildings under Earthquakes in Barcelona, Spain

Abstract:   The seismic risk of the buildings of Barcelona, Spain, is analyzed by using a method based on the capacity spectrum. The seismic hazard in the area of the city is described by means of the reduced 5% damped elastic response spectrum. Obtaining fragility curves for the most important building types of an urban center requires an important amount of information about the structures and the use of nonlinear structural analysis tools. The information on the buildings of Barcelona was obtained by collecting, arranging, improving, and completing the database of the housing and current buildings. The buildings existing in Barcelona are mainly of two types: unreinforced masonry structures and reinforced concrete buildings with waffled slab floors. In addition, the Arc-View software was used to create a GIS tool for managing the collected information to develop seismic risk scenarios. This study shows that the vulnerability of the buildings is significant and therefore, in spite of the medium to low seismic hazard in the area of the city, the expected seismic risk is considerable.     

我国震后建筑安全性应急评估现状与建议

破坏性地震发生后,为了快速有效地判定震后建筑的安全性,最大限度地减少震损建筑对人员的二次伤害,在地震应急期内需开展震后建筑安全性评估工作。这对维护灾区社会稳定有重要意义。在汶川地震、芦山地震等震害调查和应急评估的基础上,总结了我国现阶段震后建筑安全性应急评估的特点,分析了国内应急评估工作中存在的不足,介绍了我国台湾地区、美国、新西兰、欧洲与日本等震后建筑应急评估研究和应用的现状,并从适用结构类型、有无定量计算、评估人员资质和评估结论等几个方面,对国外技术标准进行了对比,归纳了可借鉴的国外经验,结合正在编制的应急评估标准,从评估目标、评估时效、评估深度和评估人员等四个方面,对我国震后建筑安全性应急评估的研究和标准编制提出了建议。     

某工业学校建筑震害调查与分析

5·12汶川大地震造成四川江油工业学校建筑物破坏严重,该校建筑按7度抗震设防,遭受8度地震,震害结果表明按抗震规范设计的建筑能达到“大震不倒”的抗震设防目标,通过对该校建筑物震害调查与分析,了解不同结构形式建筑物的震害结果和抗震性能,对今后抗震设计工作可以起到借鉴作用。     

震损底框房屋层间隔震加固设计及性能分析

5.12汶川地震及随后的多次余震导致绵竹市底框房屋遭受不同程度的破坏,本文针对绵竹市典型震损底框房屋提出钢结构+层间隔震快速加固方案,给出关键构造、加固设计方法.采用该方法快速方便地确定了某震损底框房屋层间隔震加固的有关参数,非线性时程分析结果表明,钢结构+层间隔震加固方案有明显的减震效果,能够达到预期的减震目标,同时...     

Seismic,ground motion and geotechnical characteristics of the 2011 Van-Erciş and Van-Edremit earthquakes of Turkey,and assessment of geotechnical damages

Two devastating earthquakes with moment magnitudes of 7.2 and 5.6 occurred on October 23, 2011 (Van-Erci? earthquake) and November 9, 2011 (Van-Edremit earthquake), respectively, in the Van Province of the eastern Turkey. The Van-Erci? and Van-Edremit earthquakes caused 604 and 38 fatalities, respectively, and heavy damage to buildings and other structures, particularly in Erci? town and Van City. In this study, characteristics of both main shocks and their geotechnical aspects, such as local site conditions, liquefaction phenomena and associated ground deformations and slope failures are evaluated. The failures of slopes and embankments and rock falls and ground liquefaction may also be indications of diluted ground deformation caused by the earthquake fault. It seems that a wedge-like body bounded by two fault planes was uplifted. As a result of this movement, the northern shoreline of Van Lake uplifted. The November 9, 2011 Van-Edremit earthquake was triggered due to the variation of crustal stresses induced by the October 23, 2011 earthquake. The effects of local site conditions have contributed to the damage of some parts of Erci? city and its vicinity; however, the ground liquefaction was not observed in the city as anticipated. With a magnitude of 5.6, the Van-Edremit earthquake is probably the smallest magnitude earthquake to cause liquefaction in Turkey so far.     

Quantitative evaluation and improvement of seismic resilience of a tall frame shear wall structure

Tall buildings are an important part of a city, and their earthquake-induced damage or collapse will lead to heavy losses, extended repair time, and casualties. Therefore, it is essential to quantify and improve the resilience of tall buildings. To this end, this paper develops a component damage-based metric to characterize tall buildings' functionality loss and then proposes a general quantitative evaluation process to evaluate tall buildings' resilience. Next, the evaluation process is applied to a 42-story reinforced concrete frame shear wall building to demonstrate its applicability. Finally, retrofit strategies on nonstructural components are discussed to enhance the building's resilience. It can be concluded that the proposed metric can be effectively used to evaluate tall buildings' functionality loss. The building being studied has great seismic resilience, with resilience values of 99.95%, 98.68%, and 88.69% at service level earthquake (SLE), design level earthquake (DBE), and maximum considered earthquake (MCE), respectively. The influence of nonstructural components on seismic resilience is greater than that of structural components at SLE and DBE levels. It is an effective alternative to enhance the seismic resilience of tall buildings under SLE and DBE by improving the performance of partition walls, ceilings, and equipment.     

中国大陆建筑物地震灾害风险分布研究

宏观掌握我国建筑物分布和抗震能力现状,震前对政府指导建设规划、建筑物抗震加固和民众提高防灾意识,震时指挥地震应急、损失评估等工作有重要指导意义。该文在对我国各地区建筑物抗震能力开展大量抽样调查的基础上,研究经济、土地利用、设防情况、人口密度和行政区划属性等因素与区域建筑物抗震能力的相关性,建立中国大陆区域建筑物抗震能力综合分区分类方法;利用实际地震震害资料、震害预测资料及建筑物群体震害预测方法,建立不同地区各种结构类型的建筑物地震易损性矩阵;结合不同区域内所具有的各类建筑物存量,基于GIS软件平台,计算并绘制在基本设防烈度地震作用下中国大陆地震灾害风险损失分布图。文中提出一套评估区域建筑物地震灾害风险损失较为完整的思路和方法,可为生命线地震灾害风险损失和人员伤亡分布等研究提供借鉴。     

Assessment of inelastic response of buildings using force‐ and displacement‐based approaches

In recognition of the increasing importance of accurate seismic vulnerability assessment, this paper deals with procedures and the application of inelastic acceleration and displacement spectra in the seismic assessment of buildings. An identification procedure is outlined, whereby an equivalent single degree of freedom (SDOF) system is devised to represent the building. The SDOF system characteristics (stiffness, strength, post‐peak force response and ductility) are readily evaluated from observation of the seismic response of buildings and simple mechanics. The characteristics are then tuned using measurements from instrumented buildings. Based on the earthquake scenario and structural response characteristics, appropriate inelastic acceleration and displacement spectra are selected and used to ‘predict’ the response. Comparison between the measured and predicted responses for the five buildings studied in the paper confirm the feasibility of the procedure and the realism of the results. Copyright © 2000 John Wiley & Sons, Ltd.     

Seismic microzonation and building vulnerability assessment based on site characteristic and geotechnical parameters by use of Fuzzy-AHP model (a case study for Kermanshah city)

ABSTRACT

On 12th November 2017, an earthquake with a magnitude of 7.3 Richter scale in the town of Sarpol-e Zahab took place that caused lots of human casualties and devastation. After the incident, issues related to the probability of an earthquake with equal intensity and extents of similar building destruction were raised in Kermanshah city. Therefore, a seismic microzonation map of Kermanshah city has been prepared based on the geotechnical, geological, and geophysical data, and the data were analysed using Fuzzy analytic hierarchy process (AHP). In the next step, the vulnerability analysis of city buildings was carried out based on the ground-shaking map, vulnerability curves, and statistical data regarding the buildings. The results of the vulnerability rate of residential buildings indicate that 80% of residential buildings would be exposed to vulnerability from low to moderate. However, other buildings would suffer 2% fully destruction (D1), 7% very high destruction (D2) and 11% high destruction (D3), respectively. Finally, according to the obtained results, the proposed model is verified with the help of the data and observations from the Sarpol-e Zahab earthquake, which reveals that the model is in good agreement with the actual earthquake data.     

Seismic performance assessment of masonry infill reinforced concrete buildings in Eastern Canada

In Eastern Canada, most of moment resisting reinforced concrete frames with unreinforced masonry infill (MI-MRF) buildings were constructed between 1915 and 1960. These pre-code structures, in terms of seismic requirements, are considered vulnerable to earthquake due to insufficient ductility and resistance. The goal of this study is to provide a quantitative assessment of their seismic performance using fragility functions. Fragility functions represent the probability of damage that corresponds to a specific seismic intensity measure (e.g. peak ground acceleration at the site). Based on a structural characterisation study on existing buildings in Québec region, a case study three storey–three bay MI-MRF was selected as representative for mid-rise buildings. Pushover analyses were conducted on a nonlinear model of the infill frame to obtain the corresponding lateral load-deformation capacity curve. The nonlinear behaviour of the reinforced concrete beams and columns was modelled with concentrated plastic hinges at members’ ends and a modified strut-and-tie model was used for the infill to account for multiple failure modes. A simplified probabilistic nonlinear static procedure was applied to obtain the seismic demand model at increasing levels of seismic intensity. Fragility functions were then developed using an experiment-based damage model that correlate the extent of damage to the displacement demand. Damage assessment using the developed functions was conducted for an earthquake scenario compatible with the design-level seismic hazard in Quebec City with a 2% and 10% probability of exceedance in 50 years. The developed functions and methodology are particularly useful in probability-based seismic loss assessment and in planning mitigation solutions.     

Verification of performance criteria using shake table testing for the vulnerability assessment of reinforced concrete buildings

Shake table experiments are conducted to support the selection of performance criteria and to verify the inelastic modeling approach for developing the fragility functions of reinforced concrete buildings. Two frames representing the lateral force‐resisting system of a preseismic code building are tested under the effect of an earthquake record with increasing severity. Shear failure is detected in columns at a PGA of 1.28g before other failure modes, which was effectively predicted by the fiber‐based numerical model, performance criteria, and shear supply approaches adopted for vulnerability assessment. Five buildings, ranging from 2 to 40 stories, are then assessed under the effect of far‐field and near‐source earthquake records, considering the experimentally verified modeling approach and shear failure prediction models that account for flexural ductility and shear‐axial force interaction. The impact of considering shear response on the vulnerability assessment results is considerable, particularly for the lower‐height wall structures when subjected to the near‐source earthquake scenario. Higher modes dominate the behavior of wall structures, principally under the latter seismic scenario, and shift their response to shear‐controlled. Therefore, seismic scenario‐structure‐based performance criteria are adopted for developing a range of analytically derived, experimentally verified fragility functions for the earthquake loss estimation of buildings with different characteristics.     

无筋砌体结构多层住宅振动台试验与抗震性能评估

目前,我国城镇大量砌体结构老旧多层住宅面临抗震加固、功能提升等需求。为研究该类结构的抗震性能,进行一个5层无筋砌体结构模型的模拟地震振动台试验,测试分析了7度多遇地震、设防地震、罕遇地震作用下的裂缝损伤发展状况以及楼层加速度、位移、自振频率、阻尼等变化规律。同时,进行非线性有限元分析,并用基于抗震鉴定标准、基于承载能力、基于位移和延性等不同方法,评估了试验模型对应原型结构的抗震性能。结果表明：试验模型纵向在7度多遇地震、设防地震、罕遇地震作用下分别处于完好、轻微破坏和局部倒塌状态,不满足GB 50023—2009《建筑抗震鉴定标准》中对7度区A类建筑的抗震性能目标要求;罕遇地震作用下无筋砌体结构多发生薄弱层屈服破坏,整体结构延性很差,保证抗震墙面积率或楼层屈服强度系数是实现无筋砌体结构在罕遇地震作用下抗震性能目标的主要技术措施;采用基于位移的抗震性能评估方法可以客观地反映无筋砌体结构抗震性能随高宽比增大而降低的规律。     

Prediction of potential damage due to severe earthquakes

A statistical model is developed to estimate the seismic vulnerability of low- to mid-rise reinforced concrete buildings. The model is based on a novel utilization of the discriminant analysis technique of multivariate statistics. Number of stories above the ground level (N), soft story index (SSI), overhang ratio (OHR), minimum normalized lateral stiffness index (MNLSTFI), minimum normalized lateral strength index (MNLSI) and normalized redundancy score (NRS) are selected as the basic estimation variables. The earthquake damage data compiled for the 12 November 1999 Duzce earthquake are used to develop a discriminant function in terms of these estimation variables. The discriminant score obtained from the resulting discriminant function is then used to estimate the damage state of buildings ranging from no damage to collapse, with intermediate damage states of light, moderate and severe. Correct classification rates ranging between 62% and 95% obtained for the seismic damage data associated with the recent earthquakes that occurred in Turkey support the predictive ability of the proposed model.     

汶川地震离震中较远地区高层建筑抗震鉴定实例分析

汶川地震中,陕西省西安市处于远震区,该次地震对远震区高层建筑造成了不同程度的震害。通过对一幢位于远震区高层建筑的抗震鉴定,分析了远震区高层建筑的震害特点和原因,对高层建筑抗震设计和抗震措施提出了建议。     

建筑物三维分析模型及其用于结构地震反应分析的可靠性

日本理化学研究所地震防灾研究中心与加拿大英属哥伦比亚大学的研究人员合作,共同开发和进一步发展了用于研究结构物地震反应的三维分析模型,并采用该模型编制了计算机程序,用于模拟结构物的地震反应,研究地震破坏机理.运用该分析模型的建模方法和对一设有地震仪的钢筋混凝土框架建筑物进行了分析.通过将分析结果与该建筑物在1994年Northridge地震中的记录和损伤情况进行比较,验证了作者所开发的三维分析模型和计算机程序的可靠性.