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Öğe Beton basınç dayanımının ultrasonik ses dalgası yayılma hızı ile tahmin edilmesi(Dicle Üniversitesi Mühendislik Fakültesi, 2017) Zebari, Ziwar; Bedirhanoğlu, İdris; Aydın, EnverBetonarme binaların dayanımlarının hızlı bir şekilde belirlenmesinde beton dayanımının kolay bir şekilde tespiti kilit bir öneme sahiptir. Bu çalışmada beton basınç dayanımının pratik, kolay ve yapıya zarar vermeyecek bir şekilde belirlenmesi hedeflenmiştir. Bu nedenle hasarsız bir yöntem olan ultra ses dalgası yayılma hızından faydalanılmıştır. Bu çalışma çerçevesinde yapılan deneysel ve istatiksel değerlendirme çalışmaları neticesinde ultra ses dalgasının beton içindeki yayılma hızı ile beton basınç dayanımı arasında ampirik bir model geliştirilmiştir.Öğe Beton elasatisite modülünün ultrasonik ses dalgası yayılma hızı ile tahmin edilmesi(Dicle Üniversitesi Mühendislik Fakültesi, 2017) Abdullah, Vaheel; Aydın, Enver; Bedirhanoğlu, İdrisBetonun en önemli mekanik özelliklerinden olan elastisite modülünün hasarlı yöntemlerle tespiti oldukça zahmetli bir iştir. Bu çalışmada betonun elastisite modülünün daha pratik bir şekilde belirlenmesi için hasarsız yöntemlerden olan ultra ses dalgası kullanılmıştır. Bu amaçla beton silindir numuneler üretilerek bu numuneler üzerinde hem ultra ses dalgası geçiş hızı ve basınç testleri yapılmıştır. Bu deneysel veriler kullanılarak elastisite modülünün tahmini için ses dalgası geçiş hızına bağlı olan bir model geliştirilmiştir. Bu çalışmada geliştirilen model literatürdeki mevcut modeller ve veriler ile karşılaştırıldığında tahmin performansının iyi olduğu görülmüştür.Öğe Düşük dayanımlı betona sahip betonarme kısa kolonların kesme etkileri altında davranışlarının incelenmesi(Dicle Üniversitesi Mühendislik Fakültesi, 2019) Şeker, Mehmet; Bedirhanoğlu, İdrisTopraklarının önemli bir bölümü yüksek derecede deprem tehlikesi riskine sahip olan ülkemizde yapı inşaat kusurları da yüksek oranlarda mevcuttur. Deprem sırasında binanın hasar görmesinde etkin rol oynayan kusurların başında kısa kolon kesme dayanımı yetersizliği gelmektedir. Bu çalışmada bu tür zayıflıklara sahip kısa kolonlarının davranışları laboratuvarda üretilen temsili numunelerle incelenmiştir. Kolonların davranışının adım adım izlenip hasar gelişiminin ne şekilde olduğunu takip edebilmek amacı ile yükleme statik ve monotonik artan bir şekilde uygulanmıştır. Sonuç olarak üretilen numunelerin beklendiği gibi kesme hasarı ile gevrek bir şekilde göçtüğü görülmüş ve deneyler ile bu tür kısa kolonlar yatay yükler altındaki davranışları açıklanmıştır. Söz konusu kolonlar elde edilen bilgilerin bu tür kolonların güçlendirilmesinde kullanılabileceği düşünülmektedir.Öğe The effect of age on the compressive strength of concrete by using ultrasonic pulse velocity(ISEC Press, 2019) Yousif, Qadri Ahmed; Bedirhanoğlu, İdris; Aydın, Mehmet Enver; Zebari, ZiwarIn this study, the effect of age on the strength development of concrete was investigated. For this purpose, specimens casted with ready mix concrete for different grades of concrete were obtained from ready-mix concrete firms available in Diyarbakir city which is the one of the biggest cities of Turkey. A few sets with different grade of concrete cube specimens were used in the experimental work. Each set included over 40 specimens. For measuring concrete strength development, two different tests were used: ultrasonic pulse velocity testing (UPV) and uniaxial compressive strength testing. After UPV and compressive strength tests, strength development for early ages was evaluated and defined. The aim of this work is to define the path of strength development of certain grades of concrete used in the east regions of Turkey. Another aim of the work is to be able to determine concrete strength through non-destructive UPV tests. As a result, it was seen that concrete strength development for early ages is not linearly proportional to age. Further, UPV measurements can give information on the progress of concrete strength.Öğe Effect of seismic isolation on the performance of high-rise buildings with torsional instability(MDPI, 2023) Sarıtaş, Fevzi; Bedirhanoğlu, İdris; Konak, Arova; Keskin, Mehmet SalihSeismic bearings have been used to mitigate the harmful effect of the earthquakes. Torsion mode, one of the most important irregularities, generally increases the shear forces to the vertical members such as columns and shear walls in turn this may results in brittle failure of the reinforced concrete (RC) members. Accordingly, it is vital to eliminate the torsion failure mode or switch to the higher modes with lower mass contribution. This study has evaluated the seismic performance of a high-rise building with torsion mode through push-over analysis including nonlinear time history analyses. The damage conditions of RC structural members are defined considering the Eurocode definitions and general performance assessments of the building have been evaluated accordingly. Lead rubber bearings have been used for base isolation system. By using enough number of rubber bearings, the dominant torsion mode (first free vibration mode) has been shifted to higher modes. Various earthquake records have been used in non-linear dynamic analysis to evaluate the positive effects of the bearings. The results revealed that proper arrangement of rubber bearings in structural plan of ground floor can effectively improve dynamic behavior of a high rise building with torsional instability to achieve better seismic performance.Öğe Finite element modelling of masonry wall retrofitted with combination of textile-reinforced mortar and thermal insulation(Springer Science and Business Media Deutschland GmbH, 2023) Tahat, Hamza; Bedirhanoğlu, İdris; 0000-0001-6852-3041This work presents a finite element (FE) model for retrofitted masonry walls. The masonry wall was retrofitted with a combination of textile reinforced mortar (TRM) and thermal insulation. For finite element analysis, ABAQUS software has been implemented. The subject of this study is an investigation of the effectiveness of FE method in the prediction of strength and deformation capacity of retrofitted masonry walls, in addition to studying the effects of retrofitting materials on the capacity of masonry walls. Concrete damage plasticity (CDP) was implemented by utilizing the macro model approach. After the development of the FEM model, the same case studies have been carried out, and the results have been compared with experimental ones. Wall specimens tested under out-of-plane cyclic loading has been selected for FEM analysis. In the FE analysis, five parameters have been considered: a) unreinforced masonry (URM) wall as a control specimen; b) only TRM was applied to both sides of the wall without thermal insulation panels; c) TRM and thermal insulation were applied to both sides of the wall; d) only thermal insulation panels were applied to both sides of the wall without TRM systems; e) TRM and thermal insulation panels to one side of the wall (1P1W). FEM results show a good match with experiments both in terms of force and deformation. Results presented the efficacy of combining TRM with a thermal insulation panel. It has also been discovered that using thermal insulation without the TRM system increases wall capacity by a small percentage compared to integrated retrofitting or using only the TRM system. The developed model is limited to the considered parameters and more analysis is needed to generalize the FEM model.Öğe Fracture modelling of A4-80 stainless steel bolts in different bolted connection components(Elsevier Sci Ltd, 2025) Yapıcı, Orhan; Vasdravellis, George; Kong, Zhengyi; Güneş, Şahin; Bedirhanoğlu, İdrisTo accurately model the structural collapse of the stainless steel beam to column connections under extreme loading situation, it is necessary to incorporate a reliable fracture model which replicates the observed structural response of the components. Since bolt fracture quite often governs the ultimate strength and deformation capacity of bolted connections which can also lead to failure of overall joint, it is therefore important to consider the fracture in the numerical analysis of such connections. Upon recent studies on characterisation of fracture properties of austenitic stainless steel bolts, incorporation of the bolt fracture into the numerical analysis of different stainless steel components has been studied in this study. To show the reliability and validity of recently proposed fracture model for stainless steel bolts, an advanced numerical model has been developed herein to simulate the structural behaviour of different components in stainless steel bolted connections such as threaded and unthreaded bolts, bolted T-stubs and moment resisting frame. The developed numerical model has been validated against the existing experimental data and comprehensively reported. The experimental response of all considered components which ultimately failed by bolt fracture under pure tension, were all accurately predicted by the developed fracture modelling approach.Öğe Predicting the out-of-plane flexural capacity of a TRM-strengthened Unreinforced Masonry (URM) wall(Springer Science and Business Media Deutschland GmbH, 2023) Bedirhanoğlu, İdris; Tahat, Hamza; 0000-0001-6852-3041Modern structural engineering has significant hurdles in retrofitting and strengthening masonry buildings to maintain structural safety under seismic or exceptional loads. Textile reinforced mortar is one of the most important techniques to retrofit masonry buildings. Analytical investigations to assess the TRM contribution to the strengthened structures are limited in the literature Therefore, this work presents predicting the out-of-plane flexural capacity of a TRM-strengthened unreinforced masonry (URM) wall by adopting two expressions from literature. The investigation of expressions' accuracy by comparing analytical results with experimental results for 108 specimens in the database. TRM stress-strain behavior was assumed depending on the results of bond tests on TRM strips applied to the particular substrate considered and of tensile testing on the component that debonds. The results indicate that the equation developed in the literature to predict the capacity of FRP-retrofitted URM walls provides acceptable results to predict the capacity of TRM-retrofitted URM walls. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.Öğe Quantitative evaluation of the damage to RC buildings caused by the 2023 southeast Turkey earthquake sequence(SAGE Publications Inc., 2024) Pujol, Santiago; Bedirhanoğlu, İdris; Dönmez, Cemalettin; Dowgala, Jeffrey D.; Yıldırım, Meltem Eryılmaz; Klaboe, Kari; Köroğlu, Fahri BaranData from 15 earthquakes that occurred in 12 different countries are presented showing that, without better drift control, structures built with building codes allowing large seismic drifts are likely to keep leaving a wide wake of damage ranging from cracked partitions to building overturning. Following the earthquake sequence affecting southeast Turkey in 2023, a team led by Committee 133 of the American Concrete Institute surveyed nearly 250 reinforced concrete buildings in the area extending from Antakya to Malatya. Buildings ranging from 2 to 16 stories were surveyed to assess their damage and evaluate the robustness of their structures in relation to overall stiffness, as measured by the relative cross-sectional areas of structural walls and columns. The majority of the buildings were estimated to have been built in the past 10 years. Yet, the structures surveyed were observed to have amounts of structural walls and columns comparable with amounts reported after the Erzincan (1992), Duzce (1999), and Bingol (2003) Earthquakes in Turkey. These amounts are, on average, much smaller than the wall and column amounts used in Chile and Japan. Because of that lack of robustness and given the intensities of the motions reported from Antakya to Malatya (with 10 stations with peak ground velocity (PGV) of 100 cm/s or more), it is concluded that structures in this region experienced large drifts. Excessive drift (1) exposed a myriad of construction and detailing problems leading to severe structural damage and collapse, (2) induced overturning caused by p-delta for some buildings, and (3) caused widespread damage to brittle masonry partitions. The main lesson is simple: ductility is necessary but not sufficient. It is urgent that seismic drift limits are tightened in high-seismicity regions worldwide.Öğe Retrofitting of shear compression failure-critic short columns with a new technique(MDPI, 2022) Bedirhanoğlu, İdrisOne of the reasons that cause the collapse of buildings is deficient short columns, which need to be retrofitted to prevent the collapse of the building in a potential earthquake. External reinforced concrete (RC), steel plates, and fiber-reinforced polymer (FRP) jacketing are standard retrofitting methods to retrofit columns to increase their shear capacity. However, in compression shear failure, the effectiveness of steel and FRP jacketing is quite limited due to the premature buckling of the FRP and steel material. On the other hand, RC jacketing is not practical because it requires more labor and covers more architectural places. Thus, the main motivation of this study is to present the effectiveness of a new method to retrofit short columns, including those with dominated shear compression failure. For this purpose, HSPRCC (high-performance steel plate-reinforced cementitious composite) was adapted to retrofit such short columns. This method is a combination of high-performance concrete and perforated steel plates. Short-column specimens representing existing RC buildings were retrofitted using the HSPRCC and tested. Perforated steel plates anchored to the specimen by steel bolts and repair mortar are used as a matrix. The retrofitted specimens were found to exhibit much better performance both in terms of shear strength and deformation capacity. It was also observed that the retrofitting method is effective in contributing to increasing the compression shear capacity.Öğe Seismic behavior of repaired and externally FRP-jacketed short columns built with extremely low-strength concrete(ASCE - American Society of Civil Engineers, 2022) Bedirhanoğlu, İdris; İlki, Alper; Triantafillou, Thanasis C.Short columns with deficiencies of low-strength concrete and large spacing of transverse reinforcement are quite common in construction practice in many developing countries in seismically active regions. Therefore, it is important to retrofit this type of column to avoid negative consequences in the case of severe damage. External fiber-reinforced polymer (FRP) jacketing is one of the most practical methods to retrofit reinforced concrete (RC) frame members against shear actions. However, knowledge of the seismic behavior of FRP-retrofitted RC short columns is still limited. Thus, the aim of this study was to investigate the seismic response of FRP-retrofitted low-strength RC short columns with and without predamage through the testing of 11 short column specimens representing old and deficient RC buildings. Accordingly, the results of a research program on the seismic behavior of such columns and on their repair and FRP retrofitting, covering experimental and analytical phases, are presented. In the experimental phase, test results obtained for short columns, FRP-retrofitted short columns, and repaired and retrofitted short columns are documented. Test results provide important knowledge about the effects of extremely low-strength concrete, and of different levels of predamage on the behavior of FRP-retrofitted substandard short columns. In the analytical phase, the performance of relevant design documents in predicting the shear strength of such columns retrofitted with FRP jacketing was tested through the comparison of predicted and experimental results.Öğe Turkey-based Civil Engineers’ Intentional Informal Learning Experiences during the COVID-19 Pandemic(Sınırsız Eğitim ve Araştırma Derneği, 2024) Deveci, Tanju; Bedirhanoğlu, İdrisThe COVID-19 pandemic served as a disjuncture causing individuals to seek various learning opportunities, including intentional informal learning (IIL). This study investigated 190 Turkey-based civil engineers’ IIL experiences influenced by the pandemic. Data were collected using a survey with close- and open-ended questions. Results revealed that the participants’ overall IIL engagement was at a moderate level, trying to compensate for the lack of information and skills deemed essential, most of which were job-related. Although they also indicated general interest-related IIL activities, these were still related to work. Results also showed that the participants normally used internet-based learning sources and had a tendency toward communicative and collaborative IIL activities. Based on the results, training programs for civil engineers are recommended to emphasize the notion of IIL and create communicative and collaborative learning opportunities in virtual and non-virtual environments.Öğe University students’ positive and negative perceptions of lifelong learning: A metaphoric analysis(Boğaziçi Üniversitesi, 2022) Deveci, Tanju; Bedirhanoğlu, İdrisIn tertiary education, lifelong learning (LL) skills alongside technical skills need to be prioritized. Is it, however, correct to assume that all university students are familiar with LL? Even so, might some students believe that LL is a source of tension? One way to understand these aspects is through metaphors, commonly used to convey the meaning individuals attach to concepts. Thus, this study investigated 229 university students’ metaphoric perceptions of LL. Data were collected using a discourse completion task. Results revealed that the students had limited understanding of LL as reflected through their chosen metaphors. The metaphors most frequently used to define LL were “tree,” “life,” “universe” and “trip.” The students’ explanations pointed to a variety of attributes of LL, “continuity,” “limitlessness,” and “expansion of horizons” being the most frequent ones. There were also metaphors and attributes denoting negative perceptions. We recommend LL skills be made an integral part of curricula to enhance students’ potential for becoming lifelong learners.
