İnşaat Mühendisliği Bölümü Yayın Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/395
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Article Citation - WoS: 30Citation - Scopus: 33Investigation of Strengthened Low Slenderness Rc Column by Using Textile Reinforced Mortar Strip Under Axial Load(Elsevier Sci Ltd, 2022) Mercimek, Omer; Ghoroubi, Rahim; Ozdemir, Anil; Anil, Ozgur; Erbas, YasarAn experimental and numerical study was conducted to improve the critical performance of low slenderness reinforced concrete columns, such as ultimate load capacity, initial stiffness, and energy dissipation capacity, using Textile-Reinforced Mortar (TRM) strip. A total of 17 reinforced concrete columns were fabricated and tested under uni-axial compression. The effect of carbon textile type, strip width and distance, usage of carbon fiber reinforced polymer (CFRP) fan type anchors was investigated. The experimental part of the study indicated that the ultimate load capacities of reinforced concrete columns strengthened with TRM strips was increased to 1.19-1.78 times. Their initial stiffness increased to 1.01-1.99 times, and energy dissipation capacity values increased to 1.22 and 2.09 times. In addition, simulation models for the experimental specimens were created with the ABAQUS finite element software. Then the results of analyses and the experimental outputs were compared together and interpreted. Finally, using the verified FEM model, a parametric numerical study was carried out to determine the effect of the increase in the concrete compressive strength of the column on the performance of the specimens examined within the scope of the study. According to the main findings of this study, it was demonstrated that the application of the proposed TRM strips for strengthening reinforced concrete columns was a successful method.Article Citation - WoS: 14Citation - Scopus: 16Debris Flow Modelling and Hazard Assessment for a Glacier Area: a Case Study in Barsem, Tajikistan(Springer, 2023) Dincer, A. Ersin; Kalpakci, Volkan; Ozturk, Sevki; Yilmaz, KutayThis study analyses a previous debris flow hazard as a consequence of emerging risks related to climate and regional physical changes. In addition to the increasing flood frequencies, there is an increasing risk of mud or debris flow due to increasing temperature and heavy precipitation resulting in glacier melting. One of the most recent dramatic examples of the debris flow incident took place in Barsem, Tajikistan, in 2015. As a result of heavy precipitation and excess temperature, the melting of glaciers caused debris flow which ended up with a catastrophic damage at Barsem Town. In this study, a methodology for modelling debris flow and related hazard is developed by examining the 2015 incident in detail with a commercially available software, Hydrological Engineering Centre-River Analysis System (HEC-RAS). Simulations and hazard assessment of the incident suggest that assessment of debris flow hazard can be implemented similar to flood hazard. Moreover, it is seen that debris flow inundation area can be predicted accurately by low-resolution free-source digital elevation models (DEMs), while in the present work they could not predict the debris flow hazard assessment accurately. Sensitivity results also reveal that free-source DEMs with higher resolutions do not necessarily give better predictions than free-source DEMs with lower resolutions.Article Citation - WoS: 4Citation - Scopus: 10Finding the Most Suitable Existing Irrigation Dams for Small Hydropower Development in Turkey: a Gis-Fuzzy Logic Tool(Pergamon-elsevier Science Ltd, 2021) Al Bayat, Omar; Maras, H. Hakan; Kucukali, Serhat; Al Bayatı, OmarThis paper enables a screening of existing irrigation dams in order to assess and rank potential sites for small hydropower development by using a Geographic Information System (GIS)-fuzzy logic multi criteria scoring technique. The following criteria are evaluated: dam characteristics (reservoir normal level, reservoir capacity, dam purpose, dam ageing), and grid connection spatial characteristics. The proposed method estimates the suitability degree of each criterion separately and then aggregates them into a Site Suitability Index (SSI). Existing irrigation dams in Turkey are assessed in order to be utilized for hydropower development. The overall score of each candidate site is obtained and, their performance is compared for different strategies. One of the most suitable dams, Karadere, was chosen as a case study. By using the daily continuous monitored data, we showed that flow and head is highly variable during the irrigation season. Accordingly, we evaluated an innovative compact medium-head hydro turbine that can capture those fluctuations with its operational flexibility and minimal civil works. Moreover, an optimal path methodology was applied to find the best grid connection route from the dam to its nearest substation considering the site land use characteristics in order to minimize land expropriation. (c) 2021 Elsevier Ltd. All rights reserved.Article Citation - WoS: 10Citation - Scopus: 10Experimental Investigation of Bonding Behavior of Anchoraged Timber-To Joint(Springernature, 2021) Ghoroubi, Rahim; Mercimek, Omer; Sakin, Shaimaa; Anil, OzgurThe comprehensive experimental study examining the general load-displacement behavior, stress distributions and shear stress-shear-displacement behaviors in the connection area when wood structural elements are combined with adhesive or adhesive with mechanical anchorages have been found in very limited number of studies in the literature. Therefore, an experimental study was planned. In this study, the general load-displacement behavior of the timber connection regions which are connected by adhesive and mechanical anchorages together with adhesive, with varying lengths of 180, 240 and 350 mm are investigated experimentally. Besides, the effect of changing the number and location of mechanical anchorages used in the connection area on the general load-displacement behavior and shear stress-shear-displacement behavior was also investigated. Using the load-displacement graphs obtained as a result of the experimental study, a generalized material model is proposed for the shear stress-shear-displacement interfacial adhesion surface for wood-wood junction points. This material model, which is proposed for wood-wood connection points with mechanical anchors, is a model that can be useful and can be used in the analysis of structural systems containing such connections using finite element software. It is thought that the overall capacity and load-displacement behavior of structural systems containing such connection points can be calculated more realistically using the proposed interfacial material model.Article Citation - WoS: 22Citation - Scopus: 21Experimental Investigation of Damaged Square Short Rc Columns With Low Slenderness Retrofitted by Cfrp Strips Under Axial Load(Elsevier Science inc, 2020) Ghoroubi, Rahim; Mercimek, Omer; Ozdemir, Anil; Anil, OzgurThe aim of this study is to develop the retrofitting details, which will increase axial ultimate load capacity, stiffness, displacement ductility ratios, and energy dissipation capacities of short reinforced concrete (RC) low slenderness columns to avoid adverse effects on earthquake performance. The main variables examined in the experimental study are the Carbon Reinforced Fiber Polymer (CFRP) strip width used for retrofitting, the distance between CFRP strips, the use of the anchor at the overlap zone in the CFRP strips, and the placement of the CFRP strips horizontally or vertically to the column axis. For these purposes, eleven square short RC columns with a dimension of 150x150x500 mm (with low slenderness ratio: lambda = 11.5) were produced. The columns were damaged up to 50% of their axial load carrying capacity, then retrofitted with CFRP strips in different ways. The short RC columns with low slenderness ratio were tested under monotonic axial loading until they failure. By obtaining the axial load-displacement graphs of the test specimens, the ultimate axial load capacity, initial stiffness value, displacement-ductility ratios, and energy dissipation capacities are calculated and interpreted. It has been found that the most successful retrofitting detail is obtained when CFRP strips are placed perpendicular to the column axis, and CFRP fan-type anchors are used in the strip overlap region.Editorial Citation - WoS: 22Citation - Scopus: 26A Dispassionate View of Seismic-Hazard Assessment(Seismological Soc Amer, 2013) Gulkan, PolatArticle Citation - WoS: 78Citation - Scopus: 92Finding the Most Suitable Existing Hydropower Reservoirs for the Development of Pumped-Storage Schemes: an Integrated Approach(Pergamon-elsevier Science Ltd, 2014) Kucukali, SerhatThis study aims to evaluate existing hydropower reservoirs for the development of pumped-storage schemes by using multi-criteria scoring technique. This method enables a screening of existing hydropower reservoirs, in order to assess and rank potential sites for pumped-storage development. This analysis is based on the documented evidence, measured data, and site surveys. The site assessments are categorized in 6 criteria namely geometrical conditions (maximum head, head to water way length ratio, distance to grid connection), geological conditions, environmental, and social conditions. In the context of the study, 7 existing hydropower reservoirs in Turkey, each with a catchment area of more than 50 km(2), are evaluated in order to be utilized as the lower reservoirs of pumped-storage facilities. The overall score of each candidate site is obtained and, their performance is compared. The results indicate that Turkey have suitable existing hydropower reservoirs for the development of pumped-storage facilities. However, the country lacks from legal and market framework for the establishment of pumped-storage power plants. (C) 2014 Elsevier Ltd. All rights reserved.Article Citation - WoS: 32Citation - Scopus: 31Wind Energy Resource Assessment of Izmit in the West Black Sea Coastal Region of Turkey(Pergamon-elsevier Science Ltd, 2014) Kucukali, Serhat; Dinckal, CigdemThe wind energy potential of Izmit (41.19 N, 30.30 E), which is located in the West Black Sea Coastal Region of Turkey, is assessed with the statistical analysis of the gathered wind data at the 50-m height measurement mast covering the period of 06/2008-06/2009. The annual average wind speed is calculated as 6 m/s and the prevailing wind direction is ENE (60 degrees). The Weibull distribution parameters of shape and scale factor are found as 2.03 and 6.73 m/s, respectively. The measured wind speed data are compared with the data of nearby meteorological stations and the results show that there is a considerable difference between the onsite measurements and the measurements of the meteorological stations. Moreover, a turbulence analysis is carried out and the turbulence intensity is negatively correlated with the normalized height from ground level with canopy height. The energy generation performances of three different wind turbines are evaluated by using the onsite wind speed measurements and the assessment shows that the capacity factor increase by a factor of two from 17% to 34% depending on the type of the turbine. Furthermore, an economic analysis is carried out for a 50 MW wind energy project for the potential site and the proposed project benefit/cost ratio is calculated as 8. (C) 2013 Elsevier Ltd. All rights reserved.Article Citation - WoS: 49Citation - Scopus: 64Ductility of Frp-Concrete Systems: Investigations at Different Length Scales(Elsevier Sci Ltd, 2013) Lau, Denvid; Tuakta, Chakrapan; Bueyuekoeztuerk, Oral; Gunes, Oguz; Büyüköztürk, OralFiber reinforced polymer (FRP) materials have been increasingly used in the last two decades to improve various structural characteristics of reinforced concrete (RC) bridges, buildings and other structures. Ductility of the resulting FRP-concrete system plays an important role in structural performance, especially in certain applications such as earthquake resistant design of structures, where ductility and energy dissipation play a vital role. Wrapping RC columns with FRP has been shown to generally result in significant increase in ductility due to the confinement of concrete by the FRP. Other applications such as flexural strengthening of beams involve tradeoffs between ductility and the desired load capacity. Furthermore, environmental factors may adversely affect the FRP-concrete bond raising concerns about the ductility of the system due to possible premature failure modes. Characterization of these effects requires the use of more involved mechanics concepts other than the simple elastic or ultimate strength analyses. This paper focuses on characterizing ductility of the FRP-concrete systems at different length scales using a combined experimental/computational mechanics approach. Effects of several parameters on ductility, including constituent material properties and their interfaces, FRP reinforcement geometry at the macro- and meso-level, and atomistic structure at the molecular level are discussed. Integration of this knowledge will provide the basis for improved design strategies considering the ductility of FRP-concrete systems from a global as well as local perspective including interface bond behavior under various mechanical and environmental conditions. (C) 2012 Elsevier Ltd. All rights reserved.Article Citation - WoS: 17Citation - Scopus: 26Seismic Risk Assessment and Mitigation in the Antakya-Maras Region (Seramar): Empirical Studies on the Basis of Ems-98(Earthquake Engineering Research inst, 2013) Abrahamczyk, Lars; Schwarz, Jochen; Langhammer, Tobias; Genes, M. Cemal; Bikce, Murat; Kacin, Selcuk; Gulkan, PolatThe main objective of the SERAMAR project has been to utilize current tools for earthquake risk assessment and to establish a unique partnership between universities, professional associations, and local governments, which might serve as a model for similar future activities in Turkey and adjacent areas. In order to reach this goal, a thorough microzonation survey program combined with vulnerability and social preparedness studies in anticipation of a damaging seismic event were conducted. The paper is focused on activities related to surveying building stock and classifying and evaluating through the use of different levels of consideration. Empirical risk scenarios and casualty estimations are carried out for different levels of consideration under scenario earthquakes similar in size to historic events. Preliminary findings of the pilot phase are reported in terms of credible building performance and casualty estimates. For empirical studies, the building vulnerabilities are expressed in terms of vulnerability classes of EMS-98.