Lifetime seismic performance assessment for chloride-corroded reinforced concrete buildings

The main aim of this paper was to build an estimating procedure based on the static nonlinear analysis (pushover analysis) such that structural engineers can evaluate the seismic performance of a deteriorating reinforced concrete (RC) building. For engineers' convenience, this paper suggests the probabilistic deterioration prediction model and the visual estimation of deterioration degree to evaluate corrosion-induced weight loss of reinforcing steel bars. In addition, flexural and shear capacity models for a corroded column or beam are proposed and verified by full-scale corroded beam specimens, allowing engineers to simulate its nonlinear mechanical behaviour. This paper incorporates these mechanical models of corroded members into the static nonlinear analysis to construct a procedure for assessing the seismic performance of a deteriorating RC building. An elementary school at Lanyu Island, Taitung, Taiwan, is used as an example and its lifetime seismic performance is identified utilising the proposed approach.     

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。     

GB/T 38591—2020《建筑抗震韧性评价标准》解读

近年来，美国和日本等国家相继提出了城市抗震韧性的概念并进行了相关研究，对建筑结构的抗震性能要求由“安全性”提升到了“韧性”的层面。我国市场监督管理总局和标准化管理委员会于2020年3月31日联合发布了GB/T 38591—2020《建筑抗震韧性评价标准》，该标准将于2021年2月1日实施。为了帮助使用者更深入地理解标准，对抗震韧性的研究现状和我国的建筑抗震性能化设计方法进行综述，对该标准的编制背景、过程，以及各章节内容进行简要介绍，对标准的关键条文进行深入解读，详细说明了建筑抗震韧性评级流程、抗震韧性评价指标以及指标的计算方法。标准中建立了本土化的构件易损性数据库，对于建筑震后修复时间提出了明确的修复路径和计算方法，使得评级的标准更清晰统一。     

砖砌体房屋三水准抗震能力判别方法

震前对现有砖砌体房屋抗震能力的判别是对该类房屋采取有效抗震减灾措施的重要依据,对减少该类房屋在地震中的破坏有着重要的实用价值。在我国现有《建筑抗震鉴定标准》(GB 50023—2009)给出的砖砌体房屋抗震能力指数法的框架下,引入抗震能力系数法,实现与抗震设计规范相对应的砖砌体房屋基于烈度的三水准抗震能力判别方法;将其与地震动参数联系起来,给出地震动参数-破坏状态的对应关系,实现砖砌体房屋基于地震动参数的三水准抗震能力判别方法;对汶川地震中发生震害的一栋砖砌体房屋进行抗震能力判别,与实际震害相比较,吻合得很好,并对其进行了三水准抗震能力的判别,表明该房屋满足抗震设防烈度为VII度时小震不坏、中震可修、大震不倒的抗震设防要求,验证了方法是可行和有效的,对同时进行不同设防水准下房屋抗震能力的判别是实用的。     

国内外地震现场建筑物安全鉴定研究的比较

地震现场建筑物安全鉴定是地震现场应急的重要工作之一,国内外均予以了高度重视。为了在现场追求统一、科学和快速的鉴定结果,近些年来安全鉴定的研究工作正从传统的定性判定向定量方法判定过渡。该文对美国、日本、希腊和中国等国家的地震现场建筑物安全鉴定的国家标准、现场工作的实施和量化研究进行了介绍和对比。重点介绍了美国的ATC-20系列标准、日本的安全鉴定指导说明、希腊的安全鉴定程序以及我国的安全鉴定标准的内容和各历史版本的修订,详细阐述了日本、哥伦比亚和我国的安全鉴定量化算法和相应的安全鉴定系统。通过对比总结了国内外安全鉴定标准的不同之处,以及安全鉴定量化算法和系统的异同点。最后归纳得出我国安全鉴定后续研究可借鉴的国外经验,为我国标准的修订和量化算法及系统的改进提供参考。     

基于建筑抗震韧性评价标准的某教学楼抗震韧性评价分析

对传统抗震设防目标和"可恢复功能"的抗震设计理念进行了介绍,采用新编国家标准《建筑抗震韧性评价标准》中的评价方法,对一栋新建小学教学楼进行了抗震韧性评价分析,对其修复费用、修复时间和人员损失进行了评估,以确定其抗震韧性等级.结果表明,抗震韧性评价可以对建筑物抗震性能进行量化分析,提供更易理解且更有价值的性能指标;同时,...     

基于BIM和本体的建筑抗震性能评估方法研究

FEMA P-58作为新一代建筑抗震性能评估方法,可给出精细到构件层级的地震损伤后果。然而,评估所需多源异构信息缺乏有效组织与关联,知识难以共享及重用,导致评估效率低下,自动化程度有待提高。文章在对FEMA P-58解读的基础上,提出一套基于建筑信息模型(building information modelling,简称BIM)和本体的建筑抗震性能评估方法。通过构建本体对评估所需信息进行统一组织;预处理工业基础类(industry foundation class,简称IFC)文件从BIM模型中获取建筑基本信息,并识别构件拓扑关系为自动化评估做准备;在BIM建模软件与结构分析软件间进行模型转换提高结构响应分析的效率和质量;借助SWRL(semantic web rule language)和SPARQL(SPARQL protocol and RDF query language)语言分别实现评估逻辑的合理表达以及语义层面的信息查询。该方法适用于建筑在现有评估类型下各性能指标的自动化预测,并具备可扩展性,为将来评估内容增删、更新提供空间。最后,以某一建筑为例进行可行性验证,取得较为满意的成果。     

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.     

Probabilistic seismic damage assessment of reinforced concrete buildings considering directionality effects

Most of buildings and structures are usually projected according to two main axes. However, the geographical position of these buildings varies randomly. Such random distributions of the azimuthal positions of structures, in most of the cities, generally, are not accounted for when assessing their seismic risk; certainly, the direction of the seismic loads is another highly random variable. Moreover, an additional important source of uncertainty is related to the structural response, mainly due to the random character of the mechanical properties. There is a consensus that uncertainties must be considered for adequately assessing the seismic risk of structures, but these directionality effects have not been deeply explored so far. In this article, the influence of the high uncertainty involved in these input variables on the expected seismic damage is analysed. Thus, an actual earthquake, which affected the southern part of Spain, is studied. Notably, damages on a group of affected buildings, located close to the epicentre, are analysed and discussed in detail. The results show that the influence of the random azimuthal position of structures is an important source of uncertainty and that it should be taken into account when estimating the expected seismic risk in urban areas.     

GB/T 38591-2020《建筑抗震韧性评价标准》解读

近年来,美国和日本等国家相继提出了城市抗震韧性的概念并进行了相关研究,对建筑结构的抗震性能要求由"安全性"提升到了"韧性"的层面.我国市场监督管理总局和标准化管理委员会于2020年3月31日联合发布了GB/T 38591-2020《建筑抗震韧性评价标准》,该标准将于2021年2月1日实施.为了帮助使用者更深入地理解标准...     

A new proxy for ground motion selection in seismic collapse assessment of tall buildings

Tall buildings are long‐period structures that are sensitive to the long‐period content of ground motions. Selection of appropriate ground motions is an important step in seismic collapse assessment of tall buildings using nonlinear dynamic analyses. Epsilon (ε_Sa) and eta (η) are two spectral shape indicators, which have been recently proposed for ground motion selection in the technical literature. In this study, a new parameter gamma (γ) is proposed, which has considerable correlation with the collapse capacity of long‐period structures having a fundamental period greater than 1 s. This parameter is a linear combination of ε_Sa and the displacement spectrum intensity epsilon (ε_DSI). The parameter γ is obtained and optimized by applying the particle swarm optimization algorithm. Since γ has significant correlation with the collapse capacity of long‐period structures, it can be used as an efficient proxy for ground motion selection in seismic collapse assessment of tall buildings. The results of this study show that ground motion selection considering the new proxy γ causes reduction in the dispersion of structural response and also decrease in the mean annual frequency of collapse, when compared with ground motion selection based on ε_Sa and η. Copyright © 2013 John Wiley & Sons, Ltd.     

某商厦火灾后结构安全性鉴定

某商厦由于遭受火灾,导致结构出现较大损失。为了消除安全隐患,需要对该商厦进行全面的安全性检测鉴定。通过现场勘察推定火灾的主要作用区域、火场区域温度,根据灾后结构损伤现状评定构件损伤状态等级。依据现场检测鉴定结果,分析验算结构或构件过火后剩余承载能力,为后续的加固处理方案提供依据。     

某建筑底部框架-抗震墙结构的检测鉴定

某学校的食宿楼,由于要获得底部的大空间作为食堂,故采用了底部框架-抗震墙结构。文章介绍了用中小学校舍抗震鉴定标准对该房屋的结构进行结构检测与抗震安全性鉴定。     

Reliability assessment of FRP-confined concrete columns designed for buildings

Use of the FRP has been incorporated into design guidelines. Detailed probabilistic information to support selected resistance factors in code calibration exercises for Canadian design codes for the design of FRP-confined RC columns is currently lacking. Furthermore, since new load factors and companion load combination formats have been implemented in the 2005 edition of the National Building Code of Canada (NBCC), verification and calibration of the material resistance factors to be used for the design of the FRP-confined concrete columns are desirable.

The objective of this study is to verify the adequacy of and/or calibrate the concrete resistance factor φ_c for FRP-confined RC columns. Analysis results suggest that to gain economic efficiency and without compromising safety levels, φ_c = 0.75 in designing the FRP-confined RC columns can be adopted to achieve the 50 year target reliability index of about 3.5.     

砌体结构中小学校舍抗震加固探讨

通过对中小学校舍调研情况的总结,介绍了我国中小学校舍的现状,总结了现有中小学校舍在抗震措施方面存在的主要问题,对现有教学建筑可能发生的震害进行阐述,特别指出抗震加固设计中需要注意的相关规范的规定。对中小学校舍抗震加固设计提出一些建议,指出中小学校舍的设计及施工单位选择尤为重要。     

The influence of infilled panels in retrofitting interventions of existing reinforced concrete buildings: a case study

During the seismic events occurred in the last decades, the existing reinforced concrete (RC) building stock has often exhibited a significant brittle collapse of joints and secondary elements such as infill walls. A quite common strategy, in the attempt of mitigating this vulnerability, is the generalised implementation of strengthening interventions on the structural elements, even in the absence of a complete seismic assessment procedure. This paper presents some considerations about the effects induced by strengthening interventions involving the tying of the infill panels to the RC frame. Within this context, an appraisal of the actual displacement capacity and the possible alteration induced on the global collapse mechanism is provided. The analyses and discussion of results are presented with reference to an actual case study concerning a school building, which was part of a wide vulnerability assessment investigation performed in the Province of Foggia, Italy. In particular, seismic analyses performed using nonlinear static analysis procedures on the strengthened configuration and on the original structure are critically compared and discussed.     

基于性能冗余率的震损混凝土结构残余抗震性能评价

提出了一种震损钢筋混凝土结构残余抗震性能详细评价方法,该方法克服了以日本规范为代表的现有评价方法在应用于同时包含剪切破坏和弯曲破坏构件的复杂破坏模式结构时存在的局限性。该方法基于结构静力推覆分析和结构性能冗余率,能够更详细地考虑构件损伤造成的多方面的性能变化,并且能够判定复杂破坏模式结构的破坏类型及安全界限。以一栋实际震损结构作为工程实例,采用详细评价方法和日本规范评价方法研究其残余抗震性能。结果表明:详细评价方法对于复杂破坏模式结构的评价结果更合理准确;对于脆性破坏型结构,日本规范的评价结果与详细评价方法差别不大,而对于延性破坏型结构,日本规范的评价结果误差较大;另外,通过合理设置构造缝以保证构件的延性,能够显著提高结构震后的残余抗震性能。     

Performance assessment of innovative seismic resilient steel knee braced frame

Buckling restrained knee braced truss moment frame (BRKBTMF) is a novel and innovative steel structural system that utilizes the advantages of long-span trusses and dedicated structural fuses for seismic applications. Steel trusses are very economical and effective in spanning large distance. However, conventional steel trusses are typically not suitable for seismic application, due to its lack of ductility and poor energy dissipation capacity. BRKBTMF utilizes buckling restrained braces (BRBs) as the designated structural fuses to dissipate the sudden surge of earthquake energy. This allows the BRKBTMF to economically and efficiently create large span structural systems for seismic applications. In this paper, a prototype BRKBTMF office building located in Berkeley, California, USA, was designed using performance-based plastic design procedure. The seismic performance of the prototype building was assessed using the state-of-the-art finite element software, OpenSees. Detailed BRB hysteresis and advanced element removal technique was implemented. The modeling approach allows the simulation for the force-deformation response of the BRB and the force redistribution within the system after the BRBs fracture. The developed finite element model was analyzed using incremental dynamic analysis approach to quantify the seismic performance of BRKBTMF. The results show BRKBTMF has excellent seismic performance with well controlled structural responses and resistance against collapse. In addition, life cycle repair cost of BRKBTMF was assessed using the next-generation performance-based earthquake engineering framework. The results confirm that BRKBTMF can effectively control the structural and non-structural component damages and minimize the repair costs of the structure under different ranges of earthquake shaking intensities. This studies conclude that BRKBTMF is a viable and effective seismic force resisting system.     

Progressive collapse assessment of new hexagrid structural system for tall buildings

Hexagrid structure is an innovative tube‐type system. It is constructed with hexagonal exterior structural grids. The hexagrid works as an effective lateral and gravitational resisting system. This paper presents the progressive collapse‐resisting capacity of this new system and the common diagrid system based on the local failure of the structural elements in the story above the ground. The collapse behavior is evaluated by two different nonlinear static and dynamic analysis methods. This study was conducted to design two‐type 28‐story and 48‐story building models to withstand wind load for both structural systems. With the analytical results, the hexagrid has enough potential of force redistribution due to its special configuration. It is observed that the new system had high resistance to progressive collapse than diagrids in similar condition. The complementary studies illustrate that resisting progressive collapse capacity, in both hexagrid and diagrid structures, is increased by using the buckling‐restrained elements. The guidelines discussed here can help engineers to understand the mechanism of progressive collapse of the hexagrid structures. Copyright © 2013 John Wiley & Sons, Ltd.     

香港办公建筑的环境评价方法概况

简要介绍了香港办公建筑的环境评价方法和过程，这一评价方法是参照建筑机构的环境评价方法，根据香港的具体环境条件而制定的，包括办公建筑的构造和楼宇设备系统等对全球环境，区域环境和室内环境的各种影响。