Seismic Hazard Analysis Of Van Province Of Turkey

Within the framework of the performance based earthquake engineering, the seismic hazardanalysis for the Van province in Turkey is performed in probabilistic manner. It is noteworthy that, in probabilistic seismic hazard assessment, as a first stage, data from geological studies and records from the instrumental period were compiled to make a seismic sourcecharacterization for the study region. Then, a seismic hazard model by using EZ-FRISKsoftware is implemented and the probabilistic seismic hazard curves were developed based onthe selected appropriate attenuation relationships, at rock sites, with a probability ofexceedance of 2%, 10% and 50% in 50-year periods. The results of probabilistic seismic hazard analyses revealed peak acceleration values for a typical rock site as 0.47g for 50%probability of exceedance in 50 years, 1.09g for 10% probability of exceedance in 50 yearsand 1.91 g for 2% probability of exceedance in 50 years. The obtained results are comparedwith N-S&E-W component taken from Muradiye station after the earthquake which occurred on 23.10.2011 in Van, N-S & E-W component taken from Van station after thee arthquake which occurred on 9.11.2011 in Van, and the spectral responses proposed forseismic evaluation and retrofit of building structure in Turkey Earthquake Code, Section 7.At the end of this study, it is apprehended that for the performance evaluation of the existing structures Code proposed earthquake response spectra are not sufficient and the currente stimations show that the potential seismic hazard in research area of the Turkey is not well estimatedin the code.

Investigation on the Possibility of Matching Vulnerability Assessment with Field Observations for Real Structures

Assessment of exiting structures is a challenging issue that is of increasing importance in the last decades. There are, however, a number of uncertainties, which may result in unrealistic estimations of the expected demand. It is widely accepted, for example, that the uncertainties in defining the seismic loads may be one of the main reasons of non-accurate estimations of the structural response. The misprediction of the overall response may however be significantly affected also by the use of different techniques and approaches in calculation of the expected demand on the structure. This paper is focused on two real case study structures that were built in the highly influenced areas from the 1999 earthquake of Kocaeli. The characteristics of the structures, as well as the field measurements allowed the authors to work on the structures in detail and calibrate their model and findings of the analyses and assessment. The assessment approach given in the latest version of the Turkish Earthquake Code (TEC) of 2007 has been adopted to approximate the structural demand as well as the observed structural damage distribution. Results of the structural analyses based on TEC and those of the structural identification have been combined to assess the building performances, paying special attention to the possibility of matching the assessment results with the observed field data. There exist inconsistencies between the reality and the estimations, the possible reasons of which will also be discussed at the end of the paper

Displacement of the Buildings According to Site-Specific Earthquake Spectra

The probabilistic seismic hazard curves were based on appropriate attenuation relationships at rock sites with a probability of exceedance of 10% in 50 years in this study. Results from the model were compared to the response spectra proposed in Section 7 of TEC ‘07 and were found to dier in both amplitude and frequency content. The impact of these dierences has been investigated with respect to building performance evaluation. Specifically, modal capacity diagrams and response spectra have been obtained for five buildings. Based on the diagrams and spectra, peak displacements have been calculated as well, revealing significant dierences in the demand displacement curves of the buildings. As a result, damage estimates and predicted building performance will deviate from site specific performance to a greater degree. Using site-specific spectra and field data will be important for future earthquake-resistant design. One of the conclusions of the study is that the Code spectra do not oer a sucient or comprehensive enough set of seismic demands and would lead to an under estimation of seismic hazard in the region of study. Therefore, site-specific design spectra for the region should be developed which reflect the characteristics of local sites

Cost Benefit Analysis Of The Structures Designed For Alternative Seismic Hazard Levels

In this study, multiple performance objectives under the various earthquake hazard levels are investigated. In case of well defined earthquake hazard, as an alternative of classical earthquake resistant design principles, it is possible to design structures at different performances depending on structure's initial cost and economic life. In this study, costs of the structure with different performance levels are discussed.Current study is carried out on the reinforced concrete structures that are designed and analyzed for various seismic hazard levels. The aim is to determine, if the risk is released, whether the economic losses can be acceptable or not. In the study, cost of reinforced concrete ductile frames and dual systems that are designed for various seismic performances, are also compared for the economical aspects.To that end, in the first step 3, 5 and 8 storey frames and dual systems of several structures at Life Safety and Immediate Occupancy performance levels was designed for the earthquake hazards of 2% and 10% probability of exceedance in 50 years. The study reveals that if both direct and indirect effects of earthquake such as retrofitting costs, cost of temporary moving, temporary accommodation costs, cost of demolition and reconstructing the building, cost of damage to household goods and business disruption, social disturbance, are be taken into consideration, initial design performance level can be accepted as Immediate Occupancy performance level rather than Life Safety performance which is proposed current earthquake codes. The cost due to injuries and cost due to loss of lives are not included

Loss Estimation and seismic risk assessment in Eastern Turkey

Potresni rizik urbanog građevnog fonda u Turskoj dobiva na sve većoj važnosti zbog vrlo visoke potresne opasnosti kombinirane s vjerojatno oštećenim i gusto naseljenim građevnim fondom. U radu je prikazano istraživanje usmjereno na istočni dio Turske gdje su seizmički izvori kao i stupanj potresne opasnosti drugačiji. Rezultati istraživanja pokazuju da je potresna sigurnost civilnih građevina i u ovim dijelovima znatno ugrožena te da su očekivani gubici visoki i na razini "ne prihvatljivosti". U radu je dana i procjena ekonomskih gubitaka i smrtnosti, ako se ostvari neki od očekivanih potresnih scenarija.The seismic risk to urban building stock in Turkey is gaining in importance due to very high seismic hazard combined with its vulnerable and densely populated building stock. The research oriented on the eastern part of Turkey, where seismic sources and the level of seismic hazard are different, is presented in the paper. The results of the research show that the seismic safety of civil buildings is highly compromised even in this part of the country, and that expected losses are high and attain the level of "non-tolerable" losses. Economic losses and fatalities are also estimated in the paper, in case of realization of some of the expected scenarios

Seismic Performance Assessment: Sarajevo Case Study

A seismic safety assessment of the two reinforced concrete buildings, located in Sarajevo, Bosnia territory, is conducted in respect to ATC-40 method. Within the framework of the performance based earthquake engineering, at the first stage, seismo-tectonic setting of the territory was discussed, then, by using historical seismicity of the region, the seismic hazard analysis for the Sarajevo City in Bosnia is performed in probabilistic manner. The site specific uniform hazard spectra at 5% damping for 475-year return period is employed as an earthquake demand. Then building stock information of Bosnia and Herzegovina is discussed. Lastly, two typical modern building’s performance assessments are carried out

EPIdemiology of Surgery-Associated Acute Kidney Injury (EPIS-AKI) : Study protocol for a multicentre, observational trial

More than 300 million surgical procedures are performed each year. Acute kidney injury (AKI) is a common complication after major surgery and is associated with adverse short-term and long-term outcomes. However, there is a large variation in the incidence of reported AKI rates. The establishment of an accurate epidemiology of surgery-associated AKI is important for healthcare policy, quality initiatives, clinical trials, as well as for improving guidelines. The objective of the Epidemiology of Surgery-associated Acute Kidney Injury (EPIS-AKI) trial is to prospectively evaluate the epidemiology of AKI after major surgery using the latest Kidney Disease: Improving Global Outcomes (KDIGO) consensus definition of AKI. EPIS-AKI is an international prospective, observational, multicentre cohort study including 10 000 patients undergoing major surgery who are subsequently admitted to the ICU or a similar high dependency unit. The primary endpoint is the incidence of AKI within 72 hours after surgery according to the KDIGO criteria. Secondary endpoints include use of renal replacement therapy (RRT), mortality during ICU and hospital stay, length of ICU and hospital stay and major adverse kidney events (combined endpoint consisting of persistent renal dysfunction, RRT and mortality) at day 90. Further, we will evaluate preoperative and intraoperative risk factors affecting the incidence of postoperative AKI. In an add-on analysis, we will assess urinary biomarkers for early detection of AKI. EPIS-AKI has been approved by the leading Ethics Committee of the Medical Council North Rhine-Westphalia, of the Westphalian Wilhelms-University Münster and the corresponding Ethics Committee at each participating site. Results will be disseminated widely and published in peer-reviewed journals, presented at conferences and used to design further AKI-related trials. Trial registration number NCT04165369

Yapı-zemin dinamik etkileşimi

06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.ÖZET Anahtar Kelimeler: Yapı-Zemin Dinamik Etkileşimi, Sonsuz Küçük Hücreli Sonlu Elemanlar Yöntemi, Serbest Zemin Hareketi, Dinamik Analiz Bu çalışmanın amacı; zemin-yapı dinamik etkileşimi probleminin deprem hesabını, zaman tanım alanında iki boyutlu uzayda sonlu elemanlar tekniğini, altsistem yaklaşımı içinde kullanarak yapmaktır. Bu amaçla zemin-yapı ortak sistemi, birbirlerini etkileşim arakesiti ile ayıran yakın bölge ve uzak bölge olmak üzere iki parçaya bölünmüştür. Yakın zemin bölgesi sonlu elemanlar tekniği ile modellenmiştir. Böylece; zeminle ilgili her türlü geometrik, mekanik ve bünyesel süreksizliklerin gözönüne alınabilmesi, yapı temelinin zemine bağlantısı ve rijitliği ile ilgili herhangi bir kısıtlamanın olmayışı, kurulan hareket denkleminin frekanstan bağımsız olması nedeniyle zaman tanım alanında adım adım integrasyon tekniğinin uygulanabilmesi, adım adım integrasyon işlemi içinde her türlü lineer olmayan ve elasto-plastik zemin ve üstyapı davranışının göz önüne alınabilmesi sağlanmıştır. Uzak zemin bölgesinin lineer elastik davranış gösterdiği varsayımından hareketle, bu ortam, etkileşim arakesitinde yer alan düğüm noktalan serbestlik derecelerinde, birim darbe yükü davranışı olarak modellenmiştir. Uzak zemin bölgesinin birim darbe yükü davranış matrisleri, sonsuz küçük hücreli sonlu elemanlar kullanılarak elde edilmiştir. Geliştirilen yöntemin yapı-zemin ortak sistemlerine uygulanmasını göstermek ve etkileşimin önemini vurgulamak amacıyla, sayısal çözümler yapılmıştır. Yapı-zemin dinamik etkileşimini içeren deprem hesaplarında elde edilen sonuçlar; (i) zemin ortamının ve üstyapının dinamik özelliklerine bağlı olmaları yanında, gözönüne alınan depremin gelişigüzel karakterine ve özellikle frekans içeriğine bağlı olarak da değişkenlik gösterdiği; (ii) yumuşak zeminler üzerinde inşa edilen kısa periyottu yapılarda rölatif yapı yerdeğiştirmesi ve toplam taban kesme kuvvetlerinin, rijit zemin varsayımına dayanan yöntemlerle hesaplanan değerlerin üstünde kaldığı; (iii) üstyapının temele göre basıklığım ifade eden geometrik narinlik oram düşük yapılarda etkileşim kuvvetleri kısa periyotlarda, sonsuz rijit zemin durumuna göre daha yüksek değerler aldığı; (iv) zemin kayma dalgası hızı arttıkça yapı-zemin etkileşiminin üstyapı için yararlı hale geldiği vurgulanmıştır. XXVIIKeywords : Soil-Structure Interaction, Consistent Infinitesimal Finite Element Cell Method, Free-Field Motion, Dynamic Analysis In this study, a new numerical procedure is proposed for the analysis of two- dimensional dynamic soil-structure interaction. The interaction force-displacement relationship is calculated by using the consistent infinitesimal finite element cell method. Assembling the interaction force-displacement relationship of the unbounded soil medium with the equation of motion of the structure leads to the basic equations of the total dynamic system. As a result, irregular bounded medium material inhomogeneities can be processed and nonlinearity of soil can be consistently taken into account. To verify the studies, a two dimensional, plain strain, soil structure interaction system is solved in time domain. The analysis procedure performed in three steps as; first, seismic free-field input motion along the interaction horizon is determined. This is achieved by the analysis of unexcavated virgin soil in the absence of the structure. Then, assuming the far-field to be linear, dynamic boundary conditions along the interaction horizon are defined by calculating the unit- impulse response matrix of the far-field in time domain. In the third step, the analysis of the soil structure system under the action of free-field input motion determined in the first step, subject to the dynamic boundary conditions determined in the second step, is carried out. The results obtained are; (i) besides the geotechnical nature of the soil and dynamic structural properties, the random characteristics of the earthquakes may be an important contributing factor in soil structure interaction analysis; (ii) for the extremely stiff and stocky buildings constructed on relatively soft soil conditions, the calculated relative displacements and base shear forces are greater in values than the fixed-base structural systems; (iii) the building aspect ratio plays a key role in soil structure interaction effects; and (iv) as the shear wave velocity of the soil medium increases, the effects of soil-structure interaction considered beneficial for seismic response of the structures. XXVII

The need for upgrading the seismic performance objectives

The economic consequences of large earthquakes require a revolutionary change in the seismic performance objective of residential and commercial buildings. The majority of total construction costs consist of non-structural and architectural costs. Therefore, the aim of this research is to upgrade current Life Safety performance objectives and to offset adverse effects on country's economy after an occurrence of large earthquakes. However, such a proposal cannot easily prove the feasibility of cost-benefit analysis in structural design. In this paper, six generic reinforced concrete frames and dual system structures designed based on Turkish Seismic Code were used in cost analysis. The study reveals that load bearing structural systems with Immediate Occupancy performance level in seismic zones can be achieved with negligible costs

Determination of Local Site-Specific Spectra Using Probabilistic Seismic Hazard Analysis for Bitlis Province, Turkey

In this study, site-specific earthquake spectra for Bitlis province in Lake Van Basin has been obtained. It is noteworthy that, in probabilistic seismic hazard assessment, as a first stage data from geological studies and records from the instrumental period were compiled to make a seismic source characterization for the study region.The probabilistic seismic hazard curves for Bitlis were developed based on selected appropriate attenuation relationships, at rock sites, with a probability of exceedance 2%, 10% and 50% in 50 year periods. The obtained results were compared with the spectral responses proposed for seismic evaluation and retrofit of the building structure in Turkish Earthquake Code, Section 2. At the end of this study, it is apprehended that the Code proposed earthquake response spectra are not sufficient for the performance evaluation of the existing structures and the current estimations show that the potential seismic hazard research of the Turkey is underestimated in the code.Therefore, site- specific design spectra for the region should be developed, which reflect the characteristics of local sites.   Determinación de espectros de sitio específico locales a través del análisis probabilístico de amenazas sísmicas para la provincia de Bitlis, Turquía   Resumen En este estudio se obtuvieron espectros de terremoto de sitio específico para la cuenca del Lago de Van, en la provincia de Bitlis, al este de Turquía. La primera fase del trabajo consistió en una evaluación probabilística de riesgo sísmico donde se compilaron los estudios geológicos y registros del período instrumental para hacer una caracterización de fuente sísmica en la región de estudio. Las curvas de amenaza sísmica para la provincia de Bitlis se desarrollaron con base en las relaciones de atenuación apropiada seleccionadas en los sitios rocosos, con una probabilidad de exceso de 2 %, 10 % y 50 % durante 50 años. Los resultados obtenidos se compararon con las respuestas de espectro propuestas para la evaluación sísmica y modernización de estructuras contempladas en el Código de Terremoto de Turquía, en la sección 2. En la parte final de este trabajo se comprende que las respuestas de espectros de terremoto propuestos en el código no son suficientes para la evaluación de desempeño de las estructuras existentes y que las estimaciones actuales muestran que la investigación de amenazas potenciales sísmicas en Turquía está subestimada en el código. Por lo tanto, el diseño de espectros de sitio específico para la región se debe desarrollar, ya que permitiría conocer las singularidades locales