Ingenieuranalyse von Erdbebenschäden: Das Bingöl (Türkei)‐Erdbeben vom 1. Mai 2003

Engineering analysis of earthquake damage: The Bingöl (Türkiye) earthquake of May 1, 2003. Through the engineering analysis of structural damage caused by the magnitude 6.6 Bingöl (Türkiye) earthquake on May 1, 2003, an attempt is made to work out the damage‐promotive factors. The damage analyses, instrumental site investigations, and the reinterpretation of structural behaviour concentrate on reinforced‐concrete buildings which were documented on site. At this, standardized school buildings take center stage, showing different grades of damage (slight damage to total collapse) even though they are of comparable character. A scheme to evaluate the causes of structural damage will be introduced which accounts for ground motion intensity, resonance effects between site und structure, directional effects of the seismic wave propagation, as well as for features of design and construction. Besides to phenomena and typical damage pattern which had been already be observed after other worldwide earthquakes, factors will be emphasized (possibly) contributing to the amplification of seismic ground motion. This in particular concerns topographical peculiarities which even seem to be insufficiently considered by actual code provisions. Furthermore, a reinforced‐concrete frame structure, typical for the regarded region, will be subjected to the nonlinear static “pushover” analysis in order to check the plausibility between recorded ground motion of the damaging mainshock and observed structural performance, the latter to be represented by the actual state of damage pattern. A methodical procedure will be presented which can be applied to derive statements on the structural vulnerability by stiffness‐dependent capacity curves. This being mainly based on material parameters and reinforcement detailing to be documented on site.     

山西国腾房地产公司双塔小区结构设计

结合两栋高层住宅楼和一地下车库的建筑结构设计,介绍了其基础选型,结构布置及相应的计算分析结果。结果表明,工程在多遇地震作用下的多个抗震性能指标均满足相关规范的要求,结构能达到小震不坏,大震不倒的抗震设防目标。     

Das Waldkirch‐Erdbeben (Baden‐Württemberg) vom 5. Dezember 2004

The Waldkirch earthquake (Baden‐Württemberg) on Dezember 5, 2004. The Waldkirch earthquake on December 5, 2004, was the strongest event on the area of the Federal Republic of Germany since the Roermond earthquake in 1992. The shaking effects of this earthquake were perceived in neighboring areas at a distance of 200 km. During a field investigation of several days the damaged buildings in the affected area were surveyed and the regional distribution of damages documented. The paper gives an impression of the damages and attempts to derive conclusions regarding the strength of the quake (and corresponding parameters) by applying mean damage grades. Based on the damages of the buildings, the maximum observed shake effects on the scale of the EMS‐98 [8] reached the intensity of I(EMS) = VI, but didn't exceed it. This can be explained by the location of the epicenter in a sparsely populated forest area, and by the circumstance that any significant communities can only be found at a distance of 15 to 20 km. The version of the German Seismic Code DIN 4149: 1981, still valid until 2005, does not consider the affected area as a particular seismic one. Nevertheless, the low degree of damage is regarded as the consequence of respecting basic design principles. In this context the lasting and sustained contribution of a planning guide for earthquake‐resistant design, published by the Ministry of Interior Baden‐Württemberg, is recognized.     

Post-earthquake loss assessment based on structural component damage inspection for residential RC buildings

There is substantial evidence showing that the seismic performance of many existing buildings may be inadequate to resist another strong earthquake. The losses from a devastating earthquake are always huge. In order to prevent damage extension and to restore the damaged community as quickly as possible, immediate post-earthquake damage assessment is always conducted through site inspection on structural components within a restricted short period of time to screen buildings that are damaged to certain levels or in danger of collapse. Without detail financial loss estimation, engineers have to face the challenge to decide whether a badly damaged building is worth retrofitting for sustainability, or needs to be demolished because existing loss estimation models are not based on the post-earthquake damage rating system. Based on some post-earthquake damage data of RC residential buildings, this paper aims to link inspected component damage level, building damage state and direct financial loss in terms of repair to replacement cost ratio. Damage of structural components are quantified by a set of damage factors and finally integrated as a building damage indicator. Building repair to replacement cost ratio and storey repair to replacement cost ratio corresponding to various damage levels of RC residential buildings have been estimated. With these statistical data, relationships of building damage indicator to repair to replacement cost ratio has been built from regression analysis.     

Analytically derived fragility relationships for the modern high‐rise buildings in the UAE

Investigating and planning for the expected damage that may hit the earthquake‐prone areas in the UAE should be undertaken in order to predict and mitigate earthquake losses. This paper discusses a framework for developing an essential driving engine in loss estimation systems, namely fragility relationships. Six reference structures, varying in height from 10 to 60 storeys, are selected due to the concentrated economic and human assets in this class of buildings. The reference structures are designed according to the building codes and construction practice adopted in this region. Inelastic fibre‐based simulation models are developed for the buildings using a verified analysis platform, which enables monitoring the spread of yielding and cracking during the multi‐step cyclic analysis. The ground motion uncertainty is accounted for using 20 input ground motions conforming to the latest understanding of the seismo‐tectonic characteristics of the UAE. A large number of inelastic pushover and incremental dynamic collapse analyses are deployed for the reference structures to derive the fragility relationships. The study illustrates the significance of assessing the vulnerability of a population of high‐rise buildings under the effect of various seismic scenarios and the need for expanding this study to cover other classes of structures in this region. Copyright © 2010 John Wiley & Sons, Ltd.     

Framework for city‐scale building seismic resilience simulation and repair scheduling with labor constraints driven by time–history analysis

A city‐scale time–history analysis‐driven framework is proposed for the quantitative evaluation of building seismic resilience and repair scheduling with repair resource constraints. First, a calculation method for the post‐earthquake residual functionality of buildings based on engineering demand parameters is proposed. Second, the repair‐scheduling unit (RSU) concept is proposed for city‐scale repair scheduling. Moreover, two repair priority indices are introduced to evaluate the repair priority of each RSU. Next, the concept of job block is proposed to compute the repair time of an RSU with insufficient repair resources. Subsequently, the workflow of repair simulation is presented to calculate the community recovery curve and resilience index quantitatively. Finally, 68,930 residential buildings of Beijing City's 16 administrative districts are simulated to demonstrate the proposed method. The outcomes of this work are expected to be a useful reference for building seismic resilience evaluation and repair scheduling of communities. Consequently, it could be an aid to pre‐earthquake disaster risk reduction planning and post‐earthquake rapid recovery of building functionalities.     

Seismic performance and cost‐effectiveness of high‐rise buildings with increasing concrete strength

The relationship between the seismic performance and economics of high‐rise buildings when designed to different material strengths is investigated in this paper. To represent the modern high‐rise construction, five 60‐story reinforced concrete buildings with varying concrete strengths, ranging from 45 MPa to 110 MPa, are designed and detailed to fine accuracy keeping almost equal periods of vibration. Detailed fiber‐based simulation models are developed to assess the relative seismic performance of the reference structures using incremental dynamic analyses and fragility functions. It is concluded that a considerable saving in construction cost and gain in useable area are attained with increasing concrete strength. The safety margins of high‐strength concrete in tall structures may exceed those of normal‐strength concrete buildings, particularly at high ground motion intensity levels. The recommendations of this systematic study may help designers to arrive at cost‐effective designs for high‐rise buildings in earthquake‐prone regions without jeopardizing safety at different performance levels. Copyright © 2014 John Wiley & Sons, Ltd.     

考虑巨震的四级地震设防水平一致风险导向定义与决策分析

防止结构倒塌、保障生命安全是确定抗震设防标准的首要目标。抗震设防水准的决策应该从只考虑地震危险性的“一致危险”原则向考虑地震危险性区域差异和工程结构抗倒塌能力不确定性的“一致风险”原则过渡。新颁布的第五代地震动参数区划图已提出第四级设防水准“极罕遇地震”（或“巨震”）,但是现行抗震设计规范仍然采用三水准设防原则,抗震设计从当前的三水准设防原则向四水准设防原则转变已成为当前工程界迫切需要解决的问题,但是目前各国对巨震的定义还比较混乱。该文阐述四级地震设防水平决策的风险导向原理,提出确定风险导向地震设防水平的解析方法。针对我国大陆地区的地震环境和抗震设防情况,给出目标倒塌风险以及相应于巨震、大震和中震的目标条件倒塌概率的建议值。采用这些建议值以及地震危险性参数的简化确定方法,初步计算并得到了相应于四级地震设防水准的风险导向地震动参数PGA值。通过与我国现行抗震设计规范、最新版地震动参数区划图和我国学者对各级设防水准地震定义的PGA值进行对比分析,发现该文得到的巨震PGA值大于最新版地震动参数区划图定义的巨震PGA值,而小震、中震和大震的PGA值则小于我国现行抗震设计规范规定的PGA值。     

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.     

Quantifizierung der Schadenspotentiale infolge Erdbeben – Teil 2: Modellstudie Baden‐Württemberg

Assessment of damage and loss potentials due to earthquake (2): Model study Baden Wuerttemberg. For the study area of Baden‐Wuerttemberg an intensity‐oriented and thus empirical approach of seismic risk analysis is taken. Explaining the essential work steps, the proximity to reality and the scatter of the results are discussed. Regional differences in the building substance and consequences for the damage expectation to be derived thereof are illustrated. A regionalisation factor is suggested, which reflects the vulnerability of building types and leads to a modification of damage functions; it is derived from extensive data surveys from the model region. The procedures and the processing levels implemented in the model are structured transparently and presented in the paper. The scenarios refer to historical earthquakes with remarkable detailing of the available regional shake maps. For these events it can be proven that losses corresponding to the intensity are calculated if the most important influence factors from soil and building vulnerability are considered. Losses from maximum events are determined by simply increasing the intensity; for worst‐case‐scenarios the respectively strongest shake effects for all communities are superimposed summarily. By applying the gross domestic capital and other statistical property values a relative loss can be derived. The communities are differentiated regarding inhabitant numbers in order to illustrate differences in how heavily affected they are. The calculated scenarios confirm that in the model region, small and medium‐sized towns deserve more attention regarding earthquake preparation than large city centres.     

震损建筑抗震鉴定加固中地震作用取值研究

在震损建筑抗震鉴定加固中,有关地震作用取值如何调整是值得深入研究的问题。以均匀Poisson过程描述地震的概率模型,以极值分布反映地震作用的概率分布,给出了地震烈度、地面峰值加速度与水平地震影响系数最大值之间的换算关系及其危险性曲线公式;阐释了等设防烈度原则、等超越概率原则和等重现期原则的基本原理;列出了震损建筑的几种分类方法及类别。基于震损建筑的后续使用年限,提出采用等重现期原则调整其地震作用取值的办法,并列出了具体的计算步骤。研究表明：相比等设防烈度原则和等超越概率原则,等重现期原则更为合理地反映了震损建筑在后续使用年限内遭遇相当设防烈度地震的风险概率,因此更适用于震损建筑抗震鉴定加固中地震作用取值的调整。     

新疆某超高层住宅楼动力弹塑性分析

为了解新疆某高层住宅在罕遇地震下的弹塑性行为,研究构件的损伤及屈服情况,判断结构的薄弱部位及薄弱构件,并对抗震设计提供建议。通过Midas-Building建立三维数值模型,对结构进行动力弹塑性时程分析。分析结果表明:结构最大层间位移角满足1/100限值的要求,大部分连梁出现损伤,主要受力剪力墙塑性损伤较小,结构无明显的薄弱部位。该工程虽属于高烈度区的超高层建筑,但通过合理的结构布置和相应的构造措施,能达到设计规定的抗震设防目标。     

Quantifizierung der Schadenspotentiale infolge Erdbeben – Teil 1: Rekonstruktion des Bebens in der Schwäbischen Alb vom 03. September 1978

Assessment of damage and loss potentials due to earthquake (1): reconstruction of the “Albstadt” – quake in the Swabian Albs in September 03, 1978. Due to lack of strong earthquakes, there is almost no data or experience available concerning the behaviour and vulnerability of common buildings in German seismic zones. The consideration of their earthquake resistance or vulnerability is still outside the scope of official investigations. A scale is missing to calibrate results of seismic risk assessment and to prove their reliability. For these purposes, an outstanding importance has to be attested to the September 03, 1978 Earthquake in the Western Swabian Alb, the heaviest one in Germany over the last 50 years. The 1978 Albstadt earthquake provides an impression of the severity of design earthquakes (in lower range) defined by DIN 4149: 2005 for the highest zone 3. Due to the limited time elapsed since the quake, it can be assumed that the building inventory is comparable to the situation today and might be generalized to other communities in that zone today. The present study can be regarded as a continuation of research activities directed towards the assessment of damage and loss potentials in German cities initiated by Deutsches Forschungsnetzwerk Naturkatastrophen (DFNK), while introducing recently elaborated and more refined approaches. The detailed survey and documentation of damage cases provide the basis to test the applicability of the developed GIS‐based seismic risk assessment technologies to other seismic regions. For this purpose, the main damage zones and the distribution of mean damage grades in Albstadt/Tailfingen are reconstructed and the loss will be recalculated for the building inventory at the time of the quake in 1978. The vulnerability of building types is evaluated on the basis of the European Macroseismic Scale EMS‐98. The classification of EMS‐98 is used to transform the existing damage observations into a scheme of damage grades. In addition to the empirical approach, selected damage cases are examined by a recently developed evaluation tool for masonry structures, combining experience and analysis in a hybrid way to detect critical zones, as well as the extent and the level of damage. All results indicate a remarkable agreement with the reported situation.     

Seismic performance of high‐rise building with a rock‐slip isolation system with cables

To avoid the overturning hazard of high‐rise buildings with traditional isolation technology, a rock‐slip structure with cables (RSSC) was proposed to improve their seismic performance. The mechanical model was established, and the motion behaviour equation of the RSSC was derived. Shake‐table tests of the RSSC were performed, and the results were compared with the corresponding finite‐element model simulations. The influences of key structural parameters and earthquake motion characteristics were analysed. The study results showed that the RSSC could effectively reduce the internal seismic force response and interlayer deformation under a severe earthquake, as well as decrease the overturning probability. The seismic reduction effect was influenced by the prestressed force, the aspect ratio of the structure, and the friction coefficient between the superstructure and foundation as well as seismic site type. The motion equation derived in this paper can be used to theoretically predict the motion behaviour of RSSC.     

Seismic performance evaluation of slender masonry towers: a case study

Historical structures and preserving their cultural values are crucial issues for humanity, not only because of their link to important certain periods in the past, but also their unique architectural features. Although many historical structures continue to offer services while keeping their historical values, some of them are at high risk in seismic prone regions. Therefore, the understanding of their structural performance under strong ground motions has been of significant importance to the civil societies as well as engineering community. The structural systems of historical buildings, generally, consist of masonry walls or piers. The behavior of such walls is controlled by either deformation or force. Seismic performance evaluation of historical structures can be carried out within the framework of performance‐based evaluation principles. This paper mainly discusses the basic principles to be considered in performance‐based seismic evaluation of historical structures. Proposed seismic hazard levels, evaluation of existing seismic hazard, selection of earthquake ground motions as well as site geology, geological and tectonic settings of the area, seismic activity of the region and local soil conditions are needed for a thorough performance evaluation. Seismic performance evaluation of a clock tower located in eastern Turkey was accomplished based on the proposed principles. Copyright © 2015 John Wiley & Sons, Ltd.     

Performance‐based seismic rehabilitation of existing steel eccentric braced buildings in near fault ground motions

The devastating effects observed in the recent earthquakes, in terms of loss of lives as well as immediate and long‐term economic losses, have prompted the need to provide documents concerning the assessment and improvement of the structural performance of existing buildings at the time of an earthquake. In this regard, performance engineering is defined as performance‐based seismic design and rehabilitation. There are many reasons for rehabilitation of existing buildings. Changing the building's usage is one of the most common reasons. In the present study, the residential steel buildings were subject to performance‐based rehabilitation, converting to educational use. Several steel frames with dual lateral‐resistant systems (MRF–EBF) and different numbers of stories were initially designed as residential buildings. The frames were rehabilitated according to the current seismic rehabilitation codes and regulations. Cover plates were used to strengthen structural elements. Variations in structural responses were evaluated before and after retrofitting by the use of nonlinear analysis. Moreover, the performance of rehabilitated structures was evaluated, considering the gross features observed in near‐field records. Copyright © 2013 John Wiley & Sons, Ltd.     

川西藏羌石砌碉房民居抗震构造更新设计研究

川西藏羌石砌碉房民居,历经多次地震考验并沿用至今,其营造中必定蕴含科学合理的抗震设计技术。论文通过调研民居营建中的构造设计做法,揭示了石砌碉房民居多种地域抗震构造设计技术;同时为了解决现代建筑与石砌建筑之间风貌延续的矛盾,结合现代混凝土砌体抗震方法,通过创新的抗震构造设计,成功解决风貌保护与抗震设防的矛盾,从而为民居更新和民居修复提供技术支持。     

Evaluating the safe interim use of seismically deficient buildings

How long can a seismically deficient building be used until the seismic risk becomes too high to be acceptable? A model interim use plan is developed with requirements to abandon the building if retrofit is not completed in the use period. Acceptable seismic performance is keyed to American Society of Civil Engineers (ASCE) 41 levels. The acceptable occupancy or use period is limited to that which results in the same probability of performance as stated for an ASCE 7‐16–compliant building, except that the total risk in the use period is due to all possible earthquakes impacting the site, not just the maximum considered earthquake. The Thiel–Zsutty damage model is used to determine the probabilities for assigned threshold ranges where unacceptable performance can occur. Other response prediction models can be used if they provide an annual probability of a given performance level exceedance. Example applications are given for both marginally and highly deficient buildings located at 17 national sites in high and moderate seismic hazard regions and include ASCE 7 Risk Class I–IV buildings. This approach may be applied to any risk decision‐making issue for which there is an annual probability of damage exceedance.     

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。