建筑抗震设计规范

《建筑抗震设计规范（GB50011—2001）》于2001年颁布,2002年1月1日实施,其抗震设防的目标是：小震不坏、中震可修、大震不倒。一般情况下,抗震设防烈度可采用地震动参数区划图的地震基本烈度,对已编制抗震设防区划的城市,可按批准的抗震设防烈度或设计地震动参数进行抗震设防。建筑的抗震设计,除应符合抗震设计规范外,尚应符合国家现行的有关强制性标准的规定。     

用概率方法确定抗震设防标准

本文分析了现行抗震设计规范(TJ 11—78)的抗震设防标准,以随机事件发生的概率来确定抗震设防中“罕遇的大地震”与“发生概率密度最大的中、小地震”的定义。通过对地震危险性结果的统计分析,得到了“发生概率密度最大的中、小地震”,烈度与基本烈度的关系以及基本烈度分別为7、8、9度地区“罕遇的大震”烈度的对应值;为贯彻“小震不坏、大震不倒”的抗震设计原则提供了依据。     

尧帝祭祀大殿抗震性能化设计

介绍了尧帝祭祀大殿的工程概况,对该大殿进行了多遇地震、设防烈度和罕遇地震下的分析,并采用两种软件作了计算比较,均达到了建筑抗震设计规范要求的小震不坏、中震可修、大震不倒的设防目标。     

湖州某超高层结构抗震设计

以湖州市某超限高层工程设计为例,根据实际工程设防烈度与场地条件具体情况并结合建筑重要性及成本经济等考量,选取适当的性能目标和抗震措施。采用基于性能的设计方法对该超限高层在三水准地震作用下的抗震性能进行定性和定量分析,分别开展了小震弹性计算、中震弹性和不屈服分析、大震不屈服和屈服分析。通过设计使结构在不同地震作用下,满足现行抗震规范规定的"小震不坏,中震可修,大震不倒"的抗震设防目标。     

钢筋混凝土结构抗震设计中一些问题的探讨

围绕“小震不坏,中震可修,大震不倒”的抗震设计目标,讨论了钢筋混凝土结构抗震设计中地震作用取用烈度、结构刚度取值、抗震等级、强剪弱弯、柱子的轴压比、短柱、抗震墙的塑性铰区的“强剪弱弯”及边缘构件配筋、连梁刚度的折减等问题,提出了作者的意见.     

基础隔震技术在地铁上盖物业开发项目中的应用

采用有限元软件Midas Gen,对带大底盘的住宅结构进行隔震设计,在底层柱下布置橡胶隔震支座,并进行小震、大震下的非线性时程分析。结果表明:与抗震结构相比,基础隔震能明显延长自振周期,降低结构的基底剪力、层间位移角。对于带裙房的框架结构,设置隔震支座能明显提高其抗震能力,为结构提供安全储备。与传统抗震结构相比,隔震结构有明显优势。设防烈度下,减震系数为0.33,大底盘以上结构可降低设防烈度,按7度0.1g设计。在罕遇地震下,隔震层竖向拉应力以及水平变形均小于规范限值,为结构提供了安全保障。最后,将修正后的地震影响系数最大值带入抗震结构分析,计算结果与时程分析结果相近,减震效果明显,可以作为上部结构设计的依据。     

八度抗震设防区砖混结构住宅楼板设计

GBJ11—89抗震规范对于砖混结构的设计思想是:小震不坏,设防烈度可修,大震不倒。而对于大震的设防,主要是构造措施的设防。在华北地区,八度抗震设防区的砖混结构住宅多采用预制板作为楼板,若楼板处理不好,地震发生时就可能使楼板脱落,造成人员伤亡。     

钢筋混凝土高层建筑新抗震设计法

本文结合新工业与民用建筑抗震设计规范(征求意见稿)提出的“小震不坏、中震可修、大震不倒”的抗震设计基本原则,给出了小震烈度地震作用下高层结构弹性强度与变形验算以及中大震烈度地震作用下高层结构弹塑性变形验算的新抗震设计方法。     

某底层柱顶隔震结构的抗震性能分析

为研究底层柱顶隔震结构在超设防烈度地震作用下的抗震性能,以某实际结构为背景,应用有限元软件ETABS建立三维结构模型进行时程分析。研究表明：在设防烈度（7度,0.15g）中震作用下,楼层剪力减震效果显著;在超烈度（8度,0.2g）大震作用下,上部结构基本处于弹性状态,而底层完全处于弹性状态,上部结构楼层加速度反应减震效果明显。同时说明,隔震结构经过优化设计,抗震性能可以满足超设防烈度要求,抗震设防目标高于抗震结构。     

第五讲 房屋抗震的基本要求

村镇房屋抗震应以《建筑抗震设计规范》GBJ11—89为基本依据。抗震标准,按《建筑抗震设计规范》GBJ11—89适用于抗震烈度为6～9度。抗震烈度显10度区的建筑应按有关专门规定执行。 抗震设防烈度,应按国家规定权限审批、颁发文件(图件)确定。一般情况下可采用基本烈度;对做过抗震设防规划地区的村镇,可按批准的抗震设防区划(设防烈度或设计地震动参数)进行抗震设防。 我国抗震规范规定,建筑根据其重要性分为四类: 甲类建筑—特殊要求的建筑,如遇地震破坏会导致严重后果的建筑。须经国家规定的批准权限批准; 乙类建筑—国家重点抗震城市的生命线工程的建筑;     

Bridge retrofit prioritisation for ageing transportation networks subject to seismic hazards

The deteriorating state of highway bridges is traditionally ignored in estimating the seismic reliability of transportation networks. In this study, the present day seismic reliability of ageing bridges in highway networks is evaluated through a time-dependent seismic fragility analysis of typical bridge classes. An efficient algorithm based on finite-state Markov Chain Monte Carlo simulations is also presented to assess the reliability of large ageing highway bridge networks without the need to simplify the network topology. The criticality of ageing bridges is then assessed through different proposed ranking strategies to arrive at an optimised seismic retrofit prioritisation. A case study on an existing bridge network with 515 bridges in the state of South Carolina, USA reveals striking differences between results of the proposed ranking strategies and those from state-of-the-practice methods. Such differences emphasise the significance of accounting for network-level importance in seismic retrofit programs of ageing transportation networks.     

The directionality effect in the seismic risk assessment of highway networks

This study introduces the directionality effect of the ground motion in the probabilistic seismic risk assessment (PSRA) of lifeline systems. Given an earthquake scenario, the seismic wave strikes each component of the system with a different angle. The angle may vary significantly depending on the shape, the location and the orientation of the structure. An appropriate example of a lifeline system is a highway transportation network, in which under earthquake conditions the bridges are considered the most vulnerable components. The proposed PSRA model requires that the seismic fragility model is a function of a ground motion intensity measure (IM), as in the traditional risk analysis, and the angle of seismic incidence. The model was implemented in a new framework for the PSRA of highway transportation network. In addition, the framework includes new algorithms. One reduces the confidence interval of the results and one increases the computational efficiency. The example used is the highway transportation network serving the Los Angeles area, which has more than 3000 bridges. The results show a considerable difference in the system resilience with or without the seismic directionality taken into consideration. This is important for benefit/cost analysis and it represents a clear departure from the current risk analysis.     

Nonlinear Static Procedure for Seismic Vulnerability Assessment of Bridges

Abstract:   The impact of an earthquake event on the performance of a highway transportation network depends on the extent of damage sustained by its individual components, particularly bridges. Seismic damageability of bridges expressed in the form of fragility curves can easily be incorporated into the scheme of risk analysis of a highway network under the seismic hazard. In this context, this article focuses on a nonlinear static method of developing fragility curves for a typical type of concrete bridge in California. The method makes use of the capacity spectrum method (CSM) for identification of spectral displacement, which is converted to rotations at bridge column ends. To check the reliability of this current analytical procedure, developed fragility curves are compared with those obtained by nonlinear time history analysis. Results indicate that analytically developed fragility curves obtained from nonlinear static and time history analyses are consistent.     

北京市城市桥梁抗震性能的现状

目前,我国的公路桥梁抗震设计规范已经实行了三代。随着设计方法的发展和更新,按以前方法设计的或者根本没进行抗震设计的桥梁,均存在不同程度的抗震安全隐患。为此,对北京市城市桥梁进行了调查分析,选取了9座典型桥梁作为代表,选用抗震性能评估方法中的能力需求比法,对9座典型桥梁进行了详细的抗震性能评估,得出了北京市城市桥梁抗震性能的现状。     

地震作用下钢筋混凝土桥梁结构易损性分析

针对缺乏桥梁结构地震破坏数据的地区 ,考虑地震地面运动、局部工程场地条件和桥梁本身参数的不确定性 ,给出了一种地震作用下钢筋混凝土结构易损性曲线的系统性分析方法 ,对美国中东部受NewMadrid地震带影响的高速公路系统混凝土连续桥梁结构易损性进行分析 ,并给出了桥梁结构的易损性曲线 ,表明本文方法对该类地区桥梁结构的易损性分析具有适用性。     

Seismic life-cycle cost analysis of ageing highway bridges under chloride exposure conditions: modelling and recommendations

Chloride-induced corrosion of highway bridges constitutes a critical form of environmental deterioration and may result in significant escalation of seismic life-cycle costs due to increased fragility during earthquake events. Most of existing literature tends to adopt simplistic uniform area loss assumptions in lieu of potentially complex, yet realistic and more detrimental, pitting corrosion models for seismic vulnerability analysis. Since the degree of deterioration depends on the severity and duration of exposure, there exists a need to investigate the influence of uniform vs. pitting corrosion assumption on seismic life-cycle costs for varied chloride exposure conditions. A case-study example of a highway bridge in Central and Southeastern US reveals consideration of pitting corrosion as critical for extreme exposures compared to relatively minor settings. Subsequently this study provides recommendations to aid bridge engineers and stakeholders to balance between computational cost and accuracy of results to aid prompt decisions on rehabilitation of ageing bridges in different exposure conditions. A framework is also included to compute seismic life-cycle costs from generic measures of corrosion, independent of assumed exposure scenario. This framework is particularly helpful for seismic loss assessment of highway bridges in chloride exposure zones with periodic field measurements to estimate the extent of structural deterioration.     

桥梁抗震设计

分析了桥梁震害及产生原因,着重介绍了拱桥的震害形式,并从设计的角度提出了一些桥梁抗震设计中遵循的基本原则,最后分析比较了我国《建筑抗震设计规范》和《公路工程抗震规范》,从而为桥梁的抗震设计提供了理论依据。     

控制公路桥梁施工技术质量的措施探讨

随着我国交通运输业的迅速发展,公路桥梁修建工程不断增加。为了保证公路桥梁的质量,必须提高公路桥梁施工技术的质量,保证公路桥梁的安全。     

关于公路桥梁设计中的耐久性分析

较好的质量安全性、耐久性是公路桥梁设计中最关键的控制点。设计师们要在进行公路桥梁设计的过程中,对出现的安全性问题和耐久性问题进行仔细的分析。有侧重性地提出设计方法,保证公路桥梁在投入使用后满足交通车辆对安全和稳定的需要。本文对公路桥梁设计中的一些问题及原因进行了分析,希望能为公路桥梁工程提供一些参考意见。     

Seismic fragility assessment of highway bridges: a state-of-the-art review

Safety and serviceability of highway bridges, during and after an earthquake, is a prerequisite to ensure continuous transport facilities, emergency and evacuation routes. Recently, fragility curves have emerged as important decision support tools to identify the potential seismic risk and consequences during and after an earthquake. There has been a substantial increase in interest among researchers in the topic of seismic fragility assessment of highway bridges as evidenced by the growing number of published literature. Advanced computational techniques and available resources have led to the development of different methodologies for fragility assessment. This study presents a review of the different methodologies developed for seismic fragility assessment of highway bridges along with their features, limitations and applications. This study presents a review of available methodologies and identifies opportunities for future development. This study mainly focuses on the key features of different methods and applications rather than penetrating down to a critique of the associated analysis procedure or mathematical framework. It synthesises the existing information on fragility analysis, presents it in concise and useful tables, and explains different applications for different purposes, which would motivate decision-makers and stake holders to extend the application of fragility curves for more informed decision-making.