Person: DOĞANGÜN, ADEM
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DOĞANGÜN
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Publication Critical remarks on Rayleigh damping model considering the explicit scheme for the dynamic response analysis of high rise buildings(Sage Publications Inc, 2021-07-01) Mahdi, Fikrat A. L.; Fahjan, Yasin; Doğangün, Adem; Mahdi, Fikrat A. L.; DOĞANGÜN, ADEM; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği Bölümü; 0000-0002-3046-4389; 0000-0002-1867-7103; ABE-2272-2020; AAR-6126-2020This paper numerically investigates the validity of Rayleigh damping model considering explicit operator to assess the dynamic response of high rise buildings under seismic loads. Considering transverse and longitudinal seismic waves, the bending moment, shear force, axial force, and and inter story drift are evaluated for a Core wall and a frame system of 46 story each. It is found that considering the explicit scheme, the dynamic responses are amplified significantly especially for axial forces. The reported amplification can be attributed to the ignorance of stiffness proportional Rayleigh damping coefficient which is associated with the stability issue of the implemented explicit operator. The paper indicates that Rayleigh damping model does not provide the required/expected damping for the higher modes of higher frequencies hence, it is not appropriate to be used along with the explicit operator especially for buildings of wide range of frequencies. It is worth pointing out that for classical dynamic analysis which follows the implicit scheme, Rayleigh damping seems to well consider the higher modes of high frequencies with higher damping ratio in comparison to the initial mode shapes. Consequently, the literature explicit scheme should be revised to accurately consider a proper damping for the higher modes which is crucial to assess the total response of structures of long periods and wide range of frequencies such as high rise buildings among others.Publication Scaling of vertical component of seismic ground motion(Elsevier, 2020-10-01) ALMahdi, Fikrat; Fahjan, Yasin; Doğangün, Adem; ALMahdi, Fikrat; DOĞANGÜN, ADEM; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği Bölümü; 0000-0002-1867-7103; AAR-6126-2020; ABE-2272-2020Three-dimensional time history analysis has become a demand for the majority of updated building codes. A vast literature has addressed the selecting and scaling of horizontal component of earthquake ground motion. Meanwhile, the scaling of vertical component has been less of a concern. This paper investigates the suggestion of using the same scaling factor of horizontal component of ground motion to scale its vertical counterpart. A data set consists of 6409 mainshock records with vertical and orientation independent geometric rotated (GMRotD50) response spectra with 5% damping is used. Even though ASCE7 - 16 among other international codes recommends to use the same scaling factor for horizontal component and its vertical counterpart, this paper shows that scaling factor of vertical component trends an extreme variation from its horizontal counterpart for various soil classes, different magnitudes and over a wide range of Joyner-Boore distances. Results illustrate that the ratio of vertical to horizontal scaling factors has a strong negative relationship with the ratio of vertical to horizontal peak ground acceleration. Earthquake magnitude has no significant role on the ratio of vertical to horizontal scaling factors. A gradual increase is observed in the studied ratio over a wide range of Joyner-Boore distances. The paper ends up with simplified equations to calculate the scaling factor of vertical component in regards with the scaling factor of its GMRotD50 horizontal counterpart based on the (V/H)(PGA) ratio of the recorded components. Robust statistics manifest the goodness of the developed equations. (C) 2020 The Authors. Published by Elsevier B.V. on behalf of Faculty of Engineering, Alexandria University.Publication A period-height relationship for newly constructed mid-rise reinforced concrete buildings in Turkey(Elsevier, 2021-01-22) Kaplan, Onur; Güney, Yücel; Doğangün, Adem; DOĞANGÜN, ADEM; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği Bölümü.; 0000-0002-1867-7103; AAR-6126-2020The fundamental period is an essential parameter in the force-based design of buildings as it defines the spectral acceleration and thus the base shear force to which the building should be designed. The fundamental period can be computed based on modeling or utilizing simplified empirical relationships defined in seismic design codes. Previous studies show that the simplified equations should be region-specific and should represent the general design and the construction characteristics of the region. In this study, ambient vibration measurements were carried out on 24 newly constructed, mid-rise reinforced concrete (RC) buildings in Eskisehir, Turkey. The relationships between the fundamental periods and the building heights were examined. Through regression analysis, a simple equation was derived to estimate the elastic fundamental vibration period of mid-rise RC buildings with respect to building height. The proposed relationship was compared to the equation defined in the new Turkey Building Earthquake Code (TBEC-2018) and with the other simplified equations in different design codes and the related literature. The results showed that the fundamental period estimates of the TBEC-2018 equation are much longer than the fundamental periods of the measured buildings in this study. This overestimation may lead to unconservative base shear forces. Therefore, the proposed equation can be used in the force-based design of mid-rise RC frame buildings for conservative estimates of the fundamental period. The contribution of infill walls to the lateral stiffness of the buildings was also investigated, and some preliminary suggestions are made for the related parts in TBEC-2018.Publication Seismicity of east anatolian of Turkey and failures of infill walls induced by major earthquakes(World Scientific Publ Co Pte Ltd, 2021-03-13) Doğangün, Adem; Yön, Burak; Onat, Onur; Emin Öncü, Mehmet; Sağıroğlu, Serkan; DOĞANGÜN, ADEM; SAĞIROĞLU, SERKAN; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği Bölümü; 0000-0002-1867-7103; AAH-8862-2021; AAR-6126-2020There are three major fault zones in Turkey scattered around the country known as East Anatolian Fault (EAF), North Anatolian Fault (NAF) and Anatolian-Aegean Subduction Zone (AASZ). Last two decades, EAF has been rather quiescent compared with NAF. However, this quiescence was broken in the beginning of the millennium. The strong shaking was started in 2003 with Bingol earthquake (Mw = 6.3) and the last earthquake on the EAF is the Sivrice-Elazig (Mw = 6.8) on January 24, 2020. Strong seismicity of these faults damaged the structures severely and caused death of the habitants. This study aims to present, seismotectonic of the region, general characteristics of the earthquakes and more specifically to report structural damage of infill walls of the structure's damages caused by these earthquakes. Damage evaluation and identification of the observed infill wall damages due to 2003 Bingol, 2011 Van earthquakes and January 24, 2020 Sivrice-Elazig earthquake occurred Turkey's Eastern region, were presented, and possible solutions were suggested. Moreover, the effects of the infill walls on the behavior of structures under static and dynamic load cases are discussed that experienced in these earthquakes. Damages are classified according to formations such as in-plane or out-of-plane, evaluations and the results obtained from the discussions are presented for each category.Publication P-Y curves for laterally loaded single piles: Numerical validation(Taylor, 2021-08-23) Timurağaoğlu, Mehmet Ömer; Fahjan, Yasin; Doğangün, Adem; TİMURAĞAOĞLU, MEHMET ÖMER; DOĞANGÜN, ADEM; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği Bölümü; 0000-0002-6329-905X; 0000-0002-1867-7103; AAR-6126-2020; ABF-2355-2020Pile foundations are widely used in marine and coastal engineering structures. The correct analysis method must be used to ensure the safety of piled systems used in marine and coastal structures. Despite several methods available in the literature, the numerical method is increasingly applied for understanding the loading mechanism of pile-soil interaction under vertical, lateral, or seismic loadings. The present study focuses on the numerical validation of centrifugal test results of the single pile in dense sand under lateral loading. An extensive parametric study is carried out to validate numerical models due to the lack of experimental tests such as shear or triaxial tests. In the numerical model, the soil is represented by a kinematic hardening model, which is simple to calibrate in finite element analysis, whereas pile is modeled as an elastic material. The p-y family of the curve is back-calculated for a single pile and an algorithm is generated. Two interface models between soil and pile, namely full contact and frictional slip contact, are investigated to represent the behavior under horizontal loading. Then, the analyses are extended to vertical loading to assess the influence of interface models.Publication Investigation of snow-induced collapse in Bozuyuk market(Elsevier, 2020-12-01) ALMahdi, Fikrat; Doğangün, Adem; Genç, Fatih; Rasekh, Waheed; Timurağaoğlu, Mehmet Ömer; ALMahdi, Fıkrat; DOĞANGÜN, ADEM; Rasekh, Waheed; TİMURAĞAOĞLU, MEHMET ÖMER; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği Bölümü; 0000-0002-1867-7103; 0000-0002-6329-905X; 0000-0002-9373-9589; AAR-6126-2020; ABF-2355-2020; ABE-2272-2020; DMA-8361-2022Heavy snowfall and frost are common phenomena in some areas of Turkey. Since it is an active seismic region, most engineering efforts focus on the impact of seismic loads. Meanwhile, the evaluation of structural and non-structural damages caused by snow loads are less of a concern. Depending on region geographical characteristics, snow is considered one of the most critical loads, especially in the case of large spans industrial structures, sport facilities and malls. This study investigates the snow induced failure of Bozuyuk Market in Turkey. An evaluation of the attributed reasons behind the reported collapse is provided. To investigate the critical regions of the structural systems, a finite element model has been generated, linear and nonlinear static push-down analysis are carried out for the collapsed portion of the structure of interest. The snow load calculations are compared in regard to national standards TS 498 and TS EN 1991-1-3. It has been found that the construction defects were the primary reason behind the partially failure of the investigated roof. The paper highlights the urgent need to upgrade the national standards regarding snow loads to go along with the changes in snowfall density and frequency due to accelerated climate change.Publication Effects of material properties on the mechanical and durability behaviors of khorasan mortar mixtures: A review(Taylor, 2021-03-05) İsafça, Tuğçe; Karakuzu, Kemal; Özen, Süleyman; Doğangün, Adem; Mardani-Aghabaglou, Ali; İsafça, Tuğçe; Karakuzu, Kemal; DOĞANGÜN, ADEM; MARDANİ, ALİ; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği Bölümü; 0000-0002-9331-1339; 0000-0002-1023-3962; 0000-0002-1867-7103; 0000-0003-0326-5015; AAR-6126-2020; C-7860-2015; GBH-3020-2022; GFM-1667-2022Historical buildings are an important piece of our cultural heritage. It is important that the materials used in the preservation, repair and reinforcement applications of these structures should be compatible with the existing structure. In many of the historical buildings in Turkey, it was reported use of the Khorasan mortar as the masonry mortar and plaster. Khorasan mortar contains slaked lime as a binder, river sand, and clayey materials as aggregate, which are fired at high temperature. It was emphasized that this mortar is an essential building material widely used in the construction and repair of historical buildings from past to present. In this study, the effects of binder, aggregate, chemical admixture, organic admixture, and fiber properties on the mechanical and durability performance of Khorasan mortar and lime-based mortar mixtures were investigated. For this purpose, a comprehensive literature research was carried out on this subject. In addition, the positive and negative effects of these materials on the mortar mixture were emphasized.Publication Dynamic characteristics of minarets of hoca tabip mosque(Ediciones Univ Oviedo, 2015-01-01) Livaoğlu, Ramazan; Baştürk, Mehmet Hudai; Serhatoğlu, Cavit; Doğangün, Adem; Aenlle, ML; Pelayo, F; Canas, FJC; Prieto, MG; Hermanns, L; Rey, MJL; FraileDeLerma, A; Canteli, AF; LİVAOĞLU, RAMAZAN; SERHATOĞLU, CAVİT; DOĞANGÜN, ADEM; Uludağ Üniversitesi; Aenlle, ML; Pelayo, F; Canas, FJC; Prieto, MG; Hermanns, L; Rey, MJL; FraileDeLerma, A; Canteli, AF; 0000-0001-8484-6027; 0000-0002-1867-7103; AAH-4411-2021; AAR-6126-2020; M-6474-2014; S-4676-2019With its thousands of years of history and traces from the past, Bursa is an open-air living history museum. Unfortunately Bursa is located in the earthquake zone and many catastrophic earthquakes occurred in the past. From inscriptions, it is learned that great majority of historical buildings like mosques, madrasahs, inns were damaged by the latest earthquake occurred in 1855. Because of their slender form, minarets were influenced much more than the other structures.Because one of the most important component of liabilities of our society is to preserve and transfer this historical heritage to our posterity, another problematic issue arise on this subject is the lack of literature about minarets. This is because that minarets were built in only Islamic regions. Furthermore, literature review shows that there are only a few scientific studies about seismic behavior of this type of structures. For the mentioned reasons, in this study, dynamic characteristics of Hoca Tabip Mosque which was built in 15th century, were evaluated. One of the in situ tests, modal analysis technique was carried out and the dynamic characteristics of the minaret were captured. At the same time the construction techniques were investigated. These results were compared with those obtained from the numerical model of minaret which was constituted using in situ size measuring. Finally, it was seen that the results from two approaches correspond to each other. In conclusion, it is shown that the numerical model which was carried out in this study represent actual structure with high accuracy.Publication Effect of infill walls and plaster for a four storey r/c building(Ediciones Univ Oviedo, 2015-01-01) Kaplan, Onur; Güney, Yücel; Doğangün, Adem; Livaoğlu, Ramazan; Aenlle, ML; Pelayo, F; Canas, FJC; Prieto, MG; Hermanns, L; Rey, MJL; FraileDeLerma, A; Canteli, AF; DOĞANGÜN, ADEM; LİVAOĞLU, RAMAZAN; Uludağ Üniversitesi; Aenlle, ML; Pelayo, F; Canas, FJC; Prieto, MG; Hermanns, L; Rey, MJL; FraileDeLerma, A; Canteli, AF; 0000-0002-1867-7103; 0000-0001-8484-6027; AAR-6126-2020; S-4676-2019; M-6474-2014Infill walls are non-structural elements, which are mainly used for architectural purposes. Besides contribution of infill walls is ignored during the structural analysis, the effect of the infill walls are usually taken into account through the application of additional loads and masses appropriately distributed along the interfaces between the surrounding frame and the infill walls. In doing so, the stiffness and strength contribution of the latter elements as well as their interaction with the members of the Reinforced Concrete (RC) frame are also ignored. Practically some of the earthquake design codes like Turkish code neglect the effects of the non-structural infill walls. However the presence of infill walls significantly increases the stiffness and the strength of a frame. The reasons of this increment are high in-plane stiffness of infill and the composite action of the infill and the frame. On the other hand, plastering significantly affects the behaviour of infill walls. Thus, the dynamic characteristics of a building also affected by the mu 11 walls of building having plaster or not.The objective of this study is selected to compare the behaviour of mull walls with and without plaster by focusing on dynamic characteristics of a 4-storey residential R/C building in Eskisehir, Turkey. Natural periods, mode shapes and damping ratios of the building were determined for two different construction stages by using ambient vibration test. To obtain experimental dynamic characteristics, Enhanced Frequency Domain Decomposition (EFDD) technique was used. These 4-storey residential R/C building is located in Eskisehir, Turkey. The investigated building in which seismic loads are jointly resisted by frames and structural walls. There are only one shear wall along x-direction and four shear walls along y-direction. The floor area of the building is 400 m(2) and story heights are 2.83 m. Total area of infill walls for one storey are 5.44 m(2) and 10.75 m(2) at x-direction y-direction, respectively.As a result of this study, vibration measurements are established that, plaster significantly changed the dynamic characteristics of building. Decrease in the periods both x and y directions and also torsional period showed that the plaster increases the lateral stiffness of the infill walls and thereby it increased the lateral stiffness of the building.Publication Dynamic response of traditional and buttressed reinforced concrete minarets(Pergamon-Elsevier Science, 2015-03-01) Türkeli, Erdem; Livaoğlu, Ramazan; Doğangün, Adem; LİVAOĞLU, RAMAZAN; DOĞANGÜN, ADEM; Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği Bölümü.; 0000-0001-8484-6027; 0000-0002-1867-7103; M-6474-2014; S-4676-2019; AAR-6126-2020The destructive 17 August 1999 M-w 7.4 Kocaeli and 12 November 1999 M-w 7.2 Duzce Earthquake caused significant damage on reinforced concrete (RC) minarets and many of them severely damaged or collapsed causing the loss of lives. Damages or collapses of these RC minarets after the miserable actions of nature compel us to revise our knowledge about the dynamic response. The experiences from the catastrophic strong ground motions also dictate to the practitioners that alternative structural load carrying systems should be used and/or the seismic resistance of widely used systems should be improved. In this study, the dynamic behaviors of traditional and proposed buttressed RC minarets were compared with each other. Findings of this study show that using buttressed structural load carrying systems in the earthquake prone regions is beneficial and these supporting system behaved well when compared to traditional RC systems. (C) 2014 Elsevier Ltd. All rights reserved.