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6 Şubat 2023 tarihinde Kahramanmaraş’ın Pazarcık ve Elbistan ilçelerinde yaklaşık 9 saat arayla sırasıyla Mw 7.7 ve Mw 7.6 büyüklüğünde iki deprem meydana gelmiştir. Birbirinden bağımsız meydana gelen iki deprem geniş bir alanda hissedilmiş, deprem merkezinde ve çevre illerde büyük hasara sebep olmuştur. Çok sayıda binanın yıkıldığı ve resmi kayıtlara göre 50 binden fazla can kaybının yaşandığı 6 Şubat 2023 depremlerinin en çok etkilediği şehirler Adana, Adıyaman, Diyarbakır, Gaziantep, Hatay, Kahramanmaraş, Kilis, Malatya, Osmaniye ve Şanlıurfa’dır. Bu çalışmada depremde en çok yıkımın ve büyük can kayıplarının olduğu bu illerdeki bina stoku derlenmiştir. İncelenen bina stoku bina taşıyıcı sistemine, kullanım amacına, kat sayısına ve deprem şartnamesi zaman dilimlerine göre ilçe bazında bir araya getirilmiştir. Depremler sırasında yıkılan, ağır hasar alan ve deprem sonrasında yıkımına karar verilen binalar artık derlenen yapı stoku içerisinde yer almamaktadır. Ancak, meydana gelen depremlere ait birçok kuvvetli yer hareketi istasyonunda kaydedilen yer ivmesi kayıtları ve yaşanan depremler nedeniyle hasar gören binaların bilgisi deprem çalışmaları açısından önemli bir veri seti oluşturmaktadır. Bu bağlamda, deprem öncesi yapı stoku için deprem risk çalışmalarının yapılarak yapı stokunda yer alan bina tiplerine uygun kırılganlık eğrilerinin test edilmesi ve iyileştirilmesi mümkündür. Çalışmada sunulan verilerin deprem risklerinin gerçekçi hesaplanmasında ve bu sayede deprem risklerinin azaltılmasında alınacak önlemler konusunda önemli bir katkı sağlayacağı düşünülmektedir. Bununla beraber, derlenen yapı stoku kullanılarak farklı bölgelerde deprem tehlikesi altındaki benzer yapı stokları için kayıp hesaplarının yapılması da mümkündür.

Deprem tehlikesi, bir bölgenin sismotektonik yapısıyla ilgili bir konu iken; deprem riski, deprem tehlikesi altındaki yapıların davranışını ele alarak belirli bir zaman dilimi için sismik kayıp ve hasarların aşılma olasılıklarını ifade eder. Bu nedenle, deprem riski hesaplanırken dikkate alınan bölgedeki yapıların deprem davranışını etkileyen özelliklerinin iyi bilinmesi gerekir. Türk yapı stoku, zaman içerisinde artan nüfusa cevap verebilmek amacıyla son yıllarda hızla büyümüş, yeni konut iştahı ve değişen sosyoekonomik yapı gibi faktörler etkisinde zamana ve lokasyona göre büyük değişim göstermiştir. Ayrıca, depreme dayanıklı yapı tasarımı ile ilgili yönetmelikler ve inşaat uygulamalarındaki ilerlemeler son yıllarda yapı özelliklerinin değişmesine sebep olmuştur. Bu bağlamda, farklı zaman dilimlerinde inşa edilmiş yapıların yerel karakteristiklerini gerçekçi bir şekilde dikkate alan uygun deprem kayıp modellerinin kullanımı önem kazanmıştır. Ancak Türk yapı stoku ile ilgili çalışmalar bölgesel veya nispeten eski verilere dayalıdır. Bu çalışmada, deprem riski ve kayıp hesaplarında kullanılacak bina bilgilerinin derlenmesi ve bina tipi yapıların temsili modellerinin oluşturulması için gerekli olan istatistiki verinin üretilmesi hedeflenmiştir. Türkiye İstatistik Kurumu tarafından sağlanan 2000 Bina Sayımı verileri ve Yapı İzin İstatistikleri kullanılarak istatistiksel bir araştırma yapılmış ve elde edilen sonuçlar karşılaştırmalı olarak sunulmuştur. Bu çalışmada incelenen yeni yapı stokunun kullanım amacı, taşıyıcı sistem tipi, dolgu duvar malzemesi ve barındırdığı nüfus oranı özellikleri 2000 Bina Sayımı verileri ile karşılaştırılmış; birleştirilmiş bina veri tabanı üzerinden Türk bina stokunun yıllar içinde gösterdiği değişim ortaya konulmuştur. Sunulan istatistiki veriler deprem risk ve kayıp hesaplarında rahatlıkla kullanılabilir.

The October 30, 2020 Earthquake caused unexpectedly significant damage in İzmir considering its distance to the city. This paper evaluates the recorded ground motions, summarizes the performance of structures affected from the earthquake with emphasis on the reasons of damage. A detailed damage assessment was carried out by the Earthquake Engineering Research Center of Middle East Technical University to compile data on the damage of RC and masonry buildings. It was observed that majority of the damage was concentrated in the Bayraklı district due to its peculiar soil properties where many 7-10 story mid-rise RC buildings suffered heavy damage and collapse. The level of amplified ground motions combined with deficiencies of apparently non-code compliant buildings exacerbated the damage. The main reasons of damage were mainly attributed to the presence of soft stories, lack of proper detailing, poor construction quality, presence of heavy overhangs, and hence significant lack of code-compliance in essence. The influence of infill walls on seismic performance of deficient and inadequate buildings was clearly seen in this earthquake. This paper also discusses seismic code requirements in effect and their influence on the observed building performance. The recorded ground motions were compared with the code spectra to evaluate the performance of the buildings. The code response spectra were found to be well above the recorded ground motion spectra at the sites where significant damage was observed.

The design of supertall buildings (300m+) involves many professionals from several disciplines. The need for coordination among numerous experts, increases complexity of the entire process, which is typically conducted under the leadership of the architect, or sometimes the contractor. Consequently, the architects designing supertall buildings must be aware of architectural and structural design considerations and their interrelations. In this paper, the main architectural design considerations and structural system details of supertall buildings are studied; these include 93 completed or under construction buildings from the 1980s onwards. This study analyses the contemporary trends in main architectural and structural design considerations and corresponding interrelations. In addition, more inclusive and consistent classifications of structural system, building form, and core planning are proposed. The comparison between design considerations over the new proposed classifications is intended to aid and direct architects in the planning and development of supertall building projects as a basic guideline.

Seismic assessment of gravity dams is generally carried out using time history analyses. Scaling of the motions is commonly used; however, in contrast to buildings, the performance of scaling procedures at predicting the mean and reducing the dispersion in engineering demand parameters (EDPs) is not known. The main goal of this study is to assess the performance of different scaling procedures in predicting seismic demands on dams. The performance regarding the prediction of the damage and the required number of motions for effective analysis was investigated. The results show that techniques commonly used for moment frames should not readily be applied to these structures.

The seismic safety of dam structures is often evaluated using time history analyses conducted with a limited number of ground motions. The selection and scaling of the ground motions is usually the most effective factor determining the results of the safety assessment. The inherent variability in the ground motion as well as the difficulty of conducting the analyses for a large number of ground motions renders the selection as the most important factor in the analysis results. The guidelines for the nonlinear transient analyses of buildings, such as the one presented in ASCE/SEI-7-10, are well studied. For dams, however, it is not clear how the selection and scaling of the accelerograms should be conducted with the goals of a) consistency b) reliability and the c) practicality of the analyses. In this context, consistency implies obtaining consistent results for the same problem, reliability implies a reduction in the variability in the results while practicality implies the completion of the process with lesser effort. The selection and scaling of the ground motions for use in the nonlinear seismic analysis of the concrete gravity dams was investigated in this study with the aforementioned goals focused on the efficient prediction of the seismic demands on these structures. Three different concrete gravity dam monoliths were selected for this purpose, using 15 selected ground motions for the appropriate local site conditions. The material nonlinearity, dam-reservoir interaction and vertical component of ground motions were considered in the analyses. The engineering demand parameters were selected as the crest displacement, the maximum crest acceleration and the crack extent, a direct indicator of the damage on the monoliths. Nine different scaling methods were investigated. The effectiveness in the prediction of the mean demand and the corresponding dispersion levels were compared. The required number of motions to conduct effective analyses was determined.

One of the primary goals in tall building design is the optimum design of service core where the vertical transportation, building services, HVAC elements etc. are situated. Particularly for supertall (+300) office buildings, a significant portion of the core space is occupied by elevators when compared to the rest of the service core elements. Actually, with the utilization of recently developed elevator technologies, it is possible to decrease the elevator footprint area and thereby to decrease the service core area. Nevertheless, the core of a tall building usually is also a part of the lateral load resisting system, namely as a structural core. This study aims to investigate the effects of service core reduction which is a consequence of the elevator footprint decrease on interior and exterior tall building structures. Generic computer models of outriggered frame and framed-tube buildings with 300m height (75 story) are produced. Then, the service core area of both buildings is decreased considering the effects of recent advances in elevator technology. First, the strength and the stiffness constraints as well as serviceability of primary and reduced core buildings are evaluated in terms of code-based design loads for each outriggered frame and framed-tube structural systems. Then, primary and reduced core buildings of outriggered frame and framed-tube structural systems are compared in terms of the change in top drift to building height ratio, the increase in leasable area and to access to natural light.

In a companion article Akkar et al. (Bull Earthq Eng, doi: 10.1007/s10518-013-9461-4 , 2013a; Bull Earthq Eng, doi: 10.1007/s10518-013-9508-6 , 2013b) present a new ground-motion prediction equation (GMPE) for estimating 5 %-damped horizontal pseudo-acceleration spectral (PSA) ordinates for shallow active crustal regions in Europe and the Middle East. This study provides a supplementary viscous damping model to modify 5 %-damped horizontal spectral ordinates of Akkar et al. (Bull Earthq Eng, doi: 10.1007/s10518-013-9461-4 2013a; Bull Earthq Eng, doi: 10.1007/s10518-013-9508-6 , 2013b) for damping ratios ranging from 1 to 50 %. The paper also presents another damping model for scaling 5 %-damped vertical spectral ordinates that can be estimated from the vertical-to-horizontal (V/H) spectral ratio GMPE that is also developed within the context of this study. For consistency in engineering applications, the horizontal and vertical damping models cover the same damping ratios as noted above. The article concludes by introducing period-dependent correlation coefficients to compute horizontal and vertical conditional mean spectra (Baker in J Struct Eng 137:322–331, 2011). The applicability range of the presented models is the same as of the horizontal GMPE proposed by Akkar et al. (Bull Earthq Eng, doi: 10.1007/s10518-013-9461-4 2013a; Bull Earthq Eng, doi: 10.1007/s10518-013-9508-6 , 2013b): as for spectral periods $$0.01 \hbox { s}\le \,\hbox {T}\le \,4\hbox { s}$$ as well as PGA and PGV for V/H model; and in terms of seismological estimator parameters $$4\le \hbox {M}_\mathrm{w} \le 8, \hbox { R} \le 200 \hbox { km}, 150\hbox { m/s}\le \hbox { V}_\mathrm{S30}\le $$ 1,200 m/s, for reverse, normal and strike-slip faults. The source-to-site distance measures that can be used in the computations are epicentral $$(\hbox {R}_\mathrm{epi})$$ , hypocentral $$(\hbox {R}_\mathrm{hyp})$$ and Joyner–Boore $$(\hbox {R}_\mathrm{JB})$$ distances. The implementation of the proposed GMPEs will facilitate site-specific adjustments of the spectral amplitudes predicted from probabilistic seismic hazard assessment in Europe and the Middle East region. They can also help expressing the site-specific design ground motion in several formats. The consistency of the proposed models together with the Akkar et al. (Bull Earthq Eng, doi: 10.1007/s10518-013-9461-4 2013a; Bull Earthq Eng, doi: 10.1007/s10518-013-9508-6 , 2013b) GMPE may be advantageous for future modifications in the ground-motion definition in Eurocode 8 (CEN in Eurocode 8, Design of structures for earthquake resistance—part 1: general rules, seismic actions and rules for buildings. European Standard NF EN 1998-1, Brussels, 2004).

SUMMARY This paper evaluates a recent record selection and scaling procedure of the authors that can determine the probabilistic structural response of buildings behaving either in the elastic or post-elastic range. This feature marks a significant strength on the procedure as the probabilistic structural response distribution conveys important information on probability-based damage assessment. The paper presents case studies that show the utilization of the proposed record selection and scaling procedure as a tool for the estimation of damage states and derivation of site-specific and region-specific fragility functions. The method can be used to describe exceedance probabilities of damage limits under a certain target hazard level with known annual exceedance rate (via probabilistic seismic hazard assessment). Thus, the resulting fragility models can relate the seismicity of the region (or a site) with the resulting building performance in a more accurate manner. Under this context, this simple and computationally efficient record selection and scaling procedure can be benefitted significantly by probability-based risk assessment methods that have started to be considered as indispensable for developing robust earthquake loss models. Copyright © 2013 John Wiley & Sons, Ltd.

SUMMARY This study presents a ground-motion selection and scaling methodology that preserves the basic seismological features of the scaled records with reduced scatter in the nonlinear structural response. The methodology modifies each strong-motion recording with known fundamental seismological parameters using the estimations of ground-motion prediction equations for a given target hazard level. It provides robust estimations on target building response through scaled ground motions and calculates the dispersion about this target. This alternative procedure is not only usefulfor record scalingand selectionbut,uponits further refinement, can also be advantageous for the probabilistic methods that assess the engineering demand parameters for a given target hazard level. Case studies that compare the performance of the proposed procedure with some other record selection and scaling methods suggest its usefulness for building performance assessment and loss models. Copyright © 2012 John Wiley & Sons, Ltd.

In this study, seismic safety of low–rise and mid–rise structures, which constitute approximately 75% of the total building stock in Turkey, is investigated by generating fragility curves. The scope is 3, 5, 7, and 9–story reinforced concrete moment resisting frame structures. The uncertainties in material variability and the specific characteristics of construction practice in Turkey are taken into account in the formation of structural simulations. Two-dimensional analytical models are constructed accordingly and categorized as poor, typical, or superior corresponding to the observed seismic performance of structures after major earthquakes in Turkey. The seismic demand statistics in terms of maximum interstory drift ratio are obtained for different sets of ground motion records by performing nonlinear time history analyses. The capacity is determined in terms of limit states and the corresponding fragility curves are obtained from the probability of reaching or exceeding each limit state for different ...

This paper presents the overall procedure followed in order to assemble the most recent pan-European strong-motion databank: Reference Database for Seismic Ground-Motion in Europe (RESORCE). RESORCE is one of the products of the SeIsmic Ground Motion Assessment (SIGMA; projet-sigma.com) project. RESORCE is intended to be a single integrated accelerometric databank for Europe and surrounding areas for use in the development and testing of ground-motion models and for other engineering seismology and earthquake engineering applications. RESORCE aims to contribute to the improvement of earthquake risk studies in Europe and surrounding areas. RESORCE principally updates and extends the previous pan-European strong-motion databank (Ambraseys et al. in Bollettino di Geofisica Teorica ed Applicata 45:113-129, 2004a) with recently compiled Greek, Italian, Swiss and Turkish accelerometric archives. The updates also include earthquake-specific studies published in recent years. The current content of RESORCE includes 5,882 multi-component and uniformly processed accelerograms from 1,814 events and 1,540 strong-motion stations. The moment magnitude range covered by RESORCE is . The source-to-site distance interval extends to 587 km and distance information is given by the common point- and extended-source distance measures. The paper presents the current features of RESORCE through simple statistics that also quantify the differences in metadata and strong-motion processing with respect to the previous version of the pan-European strong-motion databank.