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Structural damage caused by terrorist attacks or explosions resulting from accidents is an essential crucial issue for civil engineering structures. After the explosion, heavy damage and total collapse occur in the structural carrier system, and these destructions can cause significant loss of life and property. This study aimed to determine the structural behavior of brick walls exposed to blast loading with different explosive weights using analytical, numerical, and experimental methods. The masonry brick walls were selected for the application and constructed in the allowed quarry area for experimental studies. 40g, 150g, and 290g of TNT, which are placed inner base center of brick walls, were used respectively to observe the progressive damage. The analytical blast responses, such as maximum pressure values etc., were calculated and predicted empirical formulas. The numerical blast responses were determined with Ansys Workbench and Autodyn software. At the end of the study, damage situations, pressures, displacement values, and energies are presented comparatively. It is observed from both experimental and numerical methods that 40g and 150g TNT explosives caused several damages on the wall. The wall collapsed on supporting points in 290g TNT explosives. It can be seen that the mean values of pressures and displacements increase respectively by three and six times, with the TNT explosive weight increasing from 40g to 290g. A good agreement is also found between the finite element results and empirical formulas proposed by Henrych and Sadovsky. However, inconsistent blasting responses are obtained with empirical formulas depending on the scaled distance.

The explosions caused by terrorism and/or accidental lead to serious damage and/or collapse in structures, economic losses, and most importantly endanger public safety. The blasting loads that can be larger than design loads are generally neglected in the design stage of civil engineering structures, despite these catastrophic effects. For these reasons, especially strategically important structures such as hospitals, military buildings, and bridges should be designed considering the blasting effects. To this aim, the effects of design parameters such as concrete strength and openings in infill walls on blasting responses of reinforced concrete (RC) buildings are investigated in this study. In situ experimental tests are firstly conducted on a test specimen constructed with brick elements to verify the finite element (FE) model criteria and assumptions. The blasting experiments are performed using 40, 150, and 290 g trinitrotoluene (TNT) explosives. Then, two RC buildings are selected as application, and blasting analyses are done with numerical and empirical methods. FE models of the buildings including structural and non-structural elements are constituted in ANSYS Workbench software. The blasting analyses are carried out with ANSYS AUTODYN software using 100 kg TNT explosives. In the analyses, two different openings in infill walls and six different concrete classes are considered. The blasting pressures, displacements, absorbed and released total energies, and damage ratios are obtained and presented as comparison parameters. The results obtained from the blasting analyses are presented with graphics and tables, comparatively. The study shows that peak pressures and maximum displacements decrease by 22.50% and 32.16% with the increase in concrete strength. Also, it is observed from numerical analyses that openings in infill walls lead to a change of 8.16% in peak pressures and 13.92% in maximum displacements.

In modal testing, the quality of vibration signals and clarity of peak points to extract the natural frequencies, corresponding mode shapes and damping ratio depend on the number and location of the sensors. High measurement costs are required for structural identification and long-term structural health monitoring in large structures, which require a high number of sensors. Therefore, the minimum number of sensors should be placed at appropriate locations on the system during experimental measurements to ensure both information of sufficient quality and cost reductions. The aim of this study is to perform cost-efficient non-destructive modal tests for a laminated composite and steel cantilever beams using an optimal sensor placement approach. Finite element models of the sample beams are constituted in ANSYS® software to determine the initial candidate set of sensor locations. Then, ambient vibration tests are conducted. Based on the experimental modal amplitudes and mode shapes, optimal sensor locations are determined using the effective independence method, and measurements are repeated. The study shows that there is good agreement between the natural frequencies and mode shapes obtained from the initial measurements and those obtained using the limited number of sensors.

Bu çalışmada, kat içinde farklı oran ve düzende yerleştirilen dolgu duvarların betonarme binaların sismik davranışlarına olan etkileri araştırılmıştır. Türkiye Bina Deprem Yönetmeliği (TBDY-2018)'ne uygun olarak tasarımı gerçekleştirilen binaların performansları zaman tanım alanında doğrusal olmayan analiz yöntemiyle tespit edilmiştir. Analizler için 11 adet deprem kaydı, yakın ve uzak fay etkileri, depremlerin büyüklüğü, zemin cinsi ve Ülkemizin faylanma mekanizması gibi parametreler dikkate alınarak seçilmiştir. Seçilen ivme kayıtları, basit ölçeklendirme yöntemi kullanılarak TBDY-2018'de verilen yatay elastik tasarım spektrumuyla uyumlu olacak şekilde ölçeklendirilmiştir. Analizlerde 5 farklı oranda dolgu duvar dikkate alınmıştır. Bu dolgu duvarlar diyagonal (eşdeğer) basınç çubuğu olarak analizlerde dikkate alınmıştır. Binanın sonlu eleman modelinde SAP2000, kesit analizlerinde ise RESPONSE2000 programı kullanılmıştır. Analizler sonucunda, her bir dolgu duvar oranı için binalardan elde edilen mod şekilleri, titreşim periyot değerleri, göreli kat ötelemesi oranları ve bina performans seviyeleri karşılaştırmalı olarak sunulmuştur., In this study, the effects of infill walls, which are placed in different ratios and configurations, on the seismic behaviors of reinforced concrete buildings are investigated. The performance levels of the buildings which are designed according to Turkish Building Earthquake Code (TBEC-2018) are determined by using nonlinear time history analysis. For the nonlinear analysis, 11 ground motion records are selected by considering several parameters such as near and far fault effects, the magnitude of earthquakes, soil type and faulting mechanism. The selected ground motion records are scaled by using simple scaling method accordance with the horizontal elastic design spectrum which is defined in TBEC-2018. In the analyses, 5 different infill wall ratios and configurations are taken into consideration and the infill walls are modeled as equivalent compression strut. The SAP2000 program and RESPONSE2000 program are used for the finite element models of the structures and cross-section analysis, respectively. As a result of the analysis, mode shapes, natural period values, interstory drift ratios and building performance levels obtained for the different infill walls ratios are presented comparatively.

Son meydana gelen depremlerde, aralarında yetersiz derz boşlukları bulunan komşu binaların birbirlerinden etkilendikleri gözlemlenmiştir. Bu etkileşim, çarpışan binaların büyük depremler sırasında ciddi zarar görmelerine veya tamamen yıkılmalarına sebep olabilir. Bu çalışmada, Türkiye’nin birinci deprem bölgesinde, eşit yüksekliklere ve farklı dinamik karakteristiklere sahip komşu betonarme binaların çarpışma davranışları incelenmiştir. Binalar arasındaki çarpışma, literatürde sıkça kullanılan lineer olmayan elastik yay (Hertz modeli) çarpışma modeli ile temsil edilmiştir. Bu çalışmada, ivme kayıtları Türk Deprem Yönetmeliğinde (TDY–2007) birinci derece deprem bölgesi için verilen tasarım spektrumuna göre ölçeklendirilmiştir. Komşu binalar, Türkiye’de çok sık kullanılan üç boyutlu kolon kiriş sistemi olarak modellenmiştir. Komşu binaların çarpışma analizleri SAP2000 program kullanılarak zaman tanım alanında analiz yöntemiyle gerçekleştirilmiştir. Birinci derece deprem bölgesinde, eşit yüksekliklere ve farklı dinamik karakteristiklere sahip komşu betonarme binaların çarpışma analizleri neticesinde çarpışma kuvvetleri elde edilmiştir. Bu çalışmanın sonucunda, TDY–2007’de tanımlanan derz miktarlarının yetersiz olduğu anlaşılmıştır. Interactions between inadequately separated neighboring buildings have been repeatedly observed during earthquakes. These interactions may result in substantial damage or even total destruction of colliding structures during strong ground motions. This study focuses on investigation of pounding response between RC buildings with equal heights and different dynamic characteristics considering Seismic Zone 1 of Turkey. A collision between buildings is represented by a pounding model commonly used in the literature, which is a nonlinear elastic spring (Hertz model). In this study, the considered ground motion records are scaled according to design spectrum given for Seismic Zone 1 in Turkish Earthquake Code 2007 (TEC–2007). Neighboring buildings are modelled as a three-dimensional beam-column system which is a widely constructed building type in Turkey. Pounding analyses of the neighboring buildings are performed in time domain by aid of SAP2000 program. Pounding forces obtained from the analyses are used to investigate the pounding response between buildings RC buildings with equal heights and different dynamic characteristics considering Seismic Zone 1 of Turkey. The results presented in this study represents that gap values defined in TEC–2007 are insufficient.

CRC Press/Balkema, 5 September 2016 through 7 September 2016 -- -- 179629, In ground motions recorded in recent major earthquakes such as 1994 Northridge earthquake in US, 1995 Kobe earthquake in Japan, 1999 Chi-Chi earthquake in Taiwan, and 1999 Kocaeli earthquake in Turkey, it has been noticed that they have large velocity pulses. The ground motions with the velocity pulses recorded in the vicinity of an earthquake fault are quite different from the usual far-fault earthquake ground motions. The velocity pulse duration in the near-fault ground motions is larger than 1.0 sec. In addition, the ratio of the Peak Ground Velocity (PGV) to the Peak Ground Acceleration (PGA) of the near-fault ground motions is larger than 0.1 sec. The ground motions having these characteristics expose the structure to high input energy in the beginning of the earthquake and cause large structural responses. Therefore, structural response to near-fault ground motions has received much attention in recent years. Interactions between neighboring, inadequately separated buildings have been repeatedly observed during earthquakes. This phenomenon often referred to as earthquake-induced structural pounding, may result in substantial damage or even total destruction of colliding structures during strong ground motions. This study focuses on effects of near-fault ground motions on earthquake-induced pounding response of RC buildings with plan irregularity. SAP2000 program is used considering the modal time history analysis method in response calculations. The results obtained from the pounding analyses for near-fault and far-fault ground motions are compared with each other. © 2016 Taylor & Francis Group, London.

Bu çalışmada 1 Mayıs 2003 depreminde yıkılmış olan üç katlı bir okul binasının çeşitli analiz yöntemleriyle deprem davranışları karşılaştırmalı olarak incelenmektedir. Binanın taşıyıcı sisteminin incelenmesinde; eşdeğer deprem yükü, mod birleştirme yöntemi ve zaman tanım alanında çözümleme yöntemi kullanılmıştır. Yapılan analizler sonucunda elde edilen yerdeğiştirme ve kesit etkileri karşılaştırmalı olarak incelenmiştir. Böylece, betonarme binaların deprem yükleri altındaki güvenliğinin belirlenmesinde statik ve dinamik çözümleme yöntemlerinin uygulaması ve sonuçları kısa olarak tartışılmıştır., In this study, a three story school building collapsed during the Bingöl earthquake on May 1, 2003 is examined by the seismic behavior of the structure defined according to different analysis methods.The methods of the equivalent earthquake load and the superposition of the modal responses as well as the solution in the time domain are used in the analysis of the structural system of the building. The displacement and internal forces obtained from results of analysis is investigated comparatively.Thus, the use of the static and dynamic analysis in the evaluation of the seismic safety of existing buildings is discussed briefly.