İnşaat Mühendisliği Bölümü Yayın Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/395
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Conference Object Performance-Based Seismic Evaluation and Retrofitting of Historic Unreinforced Concrete Wall Buildings With Interior Steel Frames(Dolnoslaskie Wydawnictwo Edukacyjne-dwe, 2012) Gunes, Oguz; Güneş, Oğuz; Gunes, Burcu; Sozenoglu, Ismet; İnşaat MühendisliğiPerformance-based seismic evaluation of historical constructions is a challenge due to the difficulty of their structural analysis that accurately captures their nonlinear behavior. This paper focuses on the use of 3-D nonlinear finite element method for static pushover analysis of unreinforced concrete (URC) wall buildings with interior steel frames for seismic evaluation and retrofit design. Three such historical school buildings with different levels of structural complexity were modeled in detail using advanced finite element programs to obtain their linear and nonlinear behavior under monotonically increasing lateral loads. The capacity curves obtained from pushover analyses were used for performance evaluation using the Capacity Spectrum Method. Retrofit design verification for one of the buildings was performed using the same approach. The results show that despite its involved modeling process and computational expense, pushover analysis of buildings with URC/URM elements using 3-D nonlinear finite element method can become a powerful practical tool for improved seismic performance evaluation and retrofit design.Conference Object On the Mechanical and Elastic Properties of Anisotropic Engineering Materials Based Upon Harmonic Representations(int Assoc Engineers-iaeng, 2013) Dinçkal, Çiğdem; Dinckal, Cigdem; İnşaat MühendisliğiThis paper presents a new aspect of harmonic decomposition method for elastic constant tensor of various anisotropic materials. Some misprints found in literature are corrected. This procedure derived here, is applied to anisotropic engineering materials possessing different elastic symmetries. In order to gain insight about these applications, numerical illustrations are presented for anisotropic engineering materials. A new description of norm in terms of harmonic tensors is introduced instead of well-known form of norm. This case is a significant innovation for specifying the anisotropy degree of any engineering materials to have opinion about the mechanical and elastic properties of these materials.Article Citation - WoS: 3Citation - Scopus: 4An Analytical Investigation of Rigid Plastic Beams Under Impact Loading(Gazi Univ, Fac Engineering Architecture, 2015) Gultop, Tekin; Gültop, Tekin; Yilmaz, Mahmut Cem; Alyavuz, Bahadir; İnşaat MühendisliğiBeams might be subjected to impact loading which is a particular type of dynamic loading during their service lives. In this study the behaviour of beams under low speed impact loading has been investigated analytically. Simply supported and fixed ended beams have been analyzed with the assumption of rigid plastic behaviour. The collapse mechanism has been assumed to emerge by the instant formation of plastic hinges, hence, a limit analysis has been performed under dynamic loading considering the conservation principles of energy and momentum. The behaviour of rigid plastic beams under impact loading has been compared to the behaviour of elastic beams under similar loading conditions.Conference Object Citation - WoS: 1Citation - Scopus: 4Orthonormal Decomposition of Third Rank Tensors and Applications(int Assoc Engineers-iaeng, 2013) Dinckal, Cigdem; Dinçkal, Çiğdem; İnşaat MühendisliğiA new procedure for representation of third rank tensors in terms of its orthonormal irreducible decomposed parts, namely as irreducible decomposition is presented. Orthonormal tensor basis method is developed by using the results of existing theory in the literature. As an example to third rank tensors, piezoelectricity tensor is decomposed by each method and results of this decomposition methods are compared for this tensor in hexagonal symmetry. As a result of comparison process, it is stated that the results for new method and other one are consistent and each decomposed parts have physical meaning. Moreover, the norm concept of piezoelectricity tensor is used to study the piezoelectric effect of some materials. It is also shown that one can determine in which material the piezoelectric effect is stronger by using the norm for different materials with the same symmetries.Article Citation - WoS: 8Citation - Scopus: 9Damage Limits for Ductile Reinforced Concrete Shear Walls(Turkish Chamber Civil Engineers, 2012) Gülkan, Hakkı Polat; Kazaz, Ilker; Gulkan, Polat; İnşaat MühendisliğiAlthough the strain based damage limits proposed in the existing Turkish Earthquake Code were adopted from reported studies of leading researchers, the appropriateness of these limit state definitions and corresponding values to evaluate the performance with the analytical tools and methods used in the displacement based design and assessment procedures has not been verified properly. The moment-curvature analysis based on the plane section hypothesis is severely violated especially for reinforced concrete walls. This indicates that a comprehensive investigation is required to investigate the validity of proposed damage limits for structural walls. This study is based on advanced and computationally rigorous numerical procedures to investigate the relation between drift ratio, plastic rotation and curvature, compressive strain in concrete and tensile strain in steel for rectangular reinforced concrete structural walls. Validity of the requirements related to deformation limits in the Turkish Seismic Code and other design guidelines is then evaluated. Modeling and acceptance criteria that are more accurate than the existing ones have been proposed for structural walls.Article Liquefaction Hazard Assessment in a Gis Environment: a Case Study of Buğday Pazarı Neighborhood in Çankırı Province(Techno-press, 2024) Ozturk, Sevki; Sarifakioglu, Ender; Yurdakul, ErenSeismic movements have varying effects on structures based on characteristics of local site. During an earthquake, weak soils are susceptible to damage due to amplified wave amplitudes. Soil -structure interaction issue has garnered increased attention in T & uuml;rkiye, after devastating earthquakes in Kocaeli G & ouml;lc & uuml;k (1999), Izmir (2020), Kahramanmara Pazarc & imath;k and Elbistan (2023). Consequently, liquefaction potential has been investigated in detail for different regions of T & uuml;rkiye, mainly with available field test results. & Ccedil;ank & imath;r & imath;, a city located close to North Anatolian Fault, is mainly built on alluvium, which is prone to liquefaction. However, no study on liquefaction hazard has been conducted thus far. In this study, groundwater level map, SPT map, and liquefaction risk map have been generated using Geographical Information System (GIS) for the Bu & gbreve;day Pazar & imath; District of & Ccedil;ank & imath;r & imath; province. Site investigations studies previously performed for 47 parcels (76 boreholes) were used within the scope of this study. The liquefaction assessment was conducted using Seed and Idriss's (1971) simplified method and the visualization of areas susceptible to liquefaction risk has been accomplished. The results of this study have been compared with the City Council's precautionary map which is currently in use. As a result of this study, it is recommended that minimum depth of boreholes in the region should be at least 30m and adequate number of laboratory tests particularly in liquefiable areas should be performed. Another important recommendation for the region is that detailed investigation should be performed by local authorities since findings of this study differ from currently used precautionary map.Article Citation - WoS: 1Citation - Scopus: 1Experimental Study on the Interaction Between Bridge Pier and Abutment Concerning Clear-Water Local Scour(Springer int Publ Ag, 2023) Akbulut, Omer Faruk; Kokpinar, Mehmet Ali; Gogus, MustafaEstimation of scour depth around bridge piers and abutments is essential for safety and economic design in alluvial rivers. Although local scour around bridge piers and abutments has been studied separately by a large number of investigators, there is limited research on the literature related to the interaction between these two structures. Hence, in this study, the aim is to investigate the interaction between bridge abutments and pier scours in detail. For this reason, bridge abutments of different lengths of La = 0.05, 0.10, and 0.15 m and a pier with diameter of D = 0.1 m were placed at various distances from each other in a long sediment channel and tested under clear-water flow conditions with constant flow intensity. All the important dimensionless parameters involved in the interaction phenomenon were derived from theoretical analysis, and the relationships between them were investigated. Analysis of the data showed that the presence of a pier in the flow medium in addition to an abutment has a certain amount of influence on the formation of scour holes around the structures. The influence of the abutment on the pier was more noticeable in the current study, particularly for longer abutments, leading to average increases of up to 20% in scour depth around the pier. The study's findings revealed that the presence of both a pier and an abutment in the flow medium exerted a discernible, unfavorable influence on the development of scour holes, particularly around piers.Conference Object Effects of Floating Rafts as Anti-Vortex Devices at Horizontal Intakes(International Association for Hydro-Environment Engineering and Research, 2023) Gogus, Mustafa; Gokmener, SerkanAir- entraining vortices created by swirling flows on intakes cause serious problems such as; increasing loss of hydraulic load and discharge at water intake structures, loss of efficiency, operational problems, cavitation and vibration problems in hydraulic machines. Hence the position of the intake should be justified for the most critical scenario as the reservoir is at dead or at minimum storage level to avoid the occurrence of air-entraining vortices. Although intakes are designed by considering the formation of air-entraining vortices, they cannot be prevented due to approach flow conditions and submergence. Therefore, some structural changes should be considered in order to avoid the occurrence of air-entraining vortices. One of these methods is using anti-vortex devices to prevent the formation of air-entraining vortices. In this experimental study, floating rafts at different sizes were tested as anti-vortex devices to prevent the formation of air-entraining vortices at single and multiplehorizontal intake structures under symmetrical and asymmetrical approach flow conditions. Three identical pipes of diameter Di=0.265 m were tested at a wide range of discharge with varying sidewall clearances. Experiments were conducted for three different combinations of the intake structures: single, double and triple water intakes were operated, respectively. Different side wall distances in the approach channels of the intake structures were specified previously to create symmetrical and asymmetrical flow conditions. The side walls were located according to these distances before each experiment. For single and double water intake structures, Wraft=10 cm and triple water intake structures, Wraft=20 cm raft width were found to be successful for vortex prevention. Moreover, Wrafts/Di values that gave successful results are 0.38 for single and double intake structures and 0.75 for triple intake structures. © 2023 IAHR – International Association for Hydro-Environment Engineering and ResearchArticle Citation - WoS: 10Citation - Scopus: 8Predicting Seismic Damage on Concrete Gravity Dams: a Review(Taylor & Francis Ltd, 2024) Arici, Yalin; Soysal, Berat FeyzaThe seismic assessment of concrete gravity dams is a problem of prediction of cracking and the corresponding consequences. With the widespread use of general-purpose finite element programs, the work in the field has shifted towards quantifying the behaviour in a framework for assessment. The nonlinear analysis and coupling with foundation-reservoir interaction, conversely, is still a challenging task. The modelling approach has significant effects on the analysis results and the assessment framework. The field remains an active area for research with many outstanding issues regarding damage quantification and assessment compared to any other major infrastructure component. A comprehensive overview of the seismic assessment of gravity dams is presented in this work with the goal to outline the issues in the field. Different models and modelling choices are compared in the context of damaged state assessment of gravity dams. The links between practical difficulties and theoretical issues are critically discussed. The aleatoric and epistemic uncertainties in the field, and their sources, are presented. Areas of future work are identified for improvement in seismic assessment as well as reducing and quantifying the uncertainties in the prediction of damaged states for concrete gravity dams.Article Citation - WoS: 3Citation - Scopus: 3Local Scour Evolution Around Semi-Circular End Bridge Abutment in Quasi-Unsteady Condition(Ice Publishing, 2022) Gokmener, Serkan; Gogus, MustafaIn this experimental study, the temporal development of local scour is studied around semi-circular end bridge abutments under quasi-unsteady clear-water flow conditions in a rectangular sediment channel. A step-wise hydrograph of 6 h duration is used in the experiments. Six different abutment lengths having constant width, with uniform sand as bed material, were tested for three different successive flows - each applied continuously for 2 h. Bathymetry of the bed level was measured around the abutment every 15 min with the help of a measurement device to observe temporal development of the local scour around the semi-circular end abutment. Effects of the abutment length, flow intensity and time on the scour depths around semi-circular end bridge abutments, along with those at the front, upstream and downstream faces of the abutment, are also investigated and discussed. It is shown that the maximum scour depth always occurs at the front noses of the abutments compared with those at the upstream and downstream noses. A dimensionless empirical formula is derived to predict the scour depth at the front nose of the abutment as a function of related parameters. The results reveal that flow intensity is the most critical parameter in scour development.