İnşaat Mühendisliği Bölümü

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Citation - WoS: 22
Citation - Scopus: 25
A dispassionate view of seismic-hazard assessment
(Seismological Soc Amer, 2013) Gulkan, Polat; 5743
Citation - WoS: 4
Citation - Scopus: 6
A Modified Applied Element Model for the Simulation of Plain Concrete Behaviour
(Emerald Group Publishing Ltd, 2023) Soysal, Berat Feyza; Arici, Yalin; Tuncay, Kagan; 157572
A modified applied element model to simulate the behaviour of plain concrete continuum structures including discrete cracking is proposed in this study. In the classical applied element model, Poisson effects are fully ignored. To remediate this issue, diagonal elements are introduced to include the Poisson effect, and the constitutive parameters are rigorously determined using the Cauchy-Born rule and the hyper-elastic theory. The formulation is validated for linear elastic problems and the consistency and convergence behaviour of the numerical approach is shown. Tensile softening formulation using the concept of fracture energy is utilised for the nonlinear range. In this range, the approach is validated using the classical benchmark tests with pure tensile, split-tensile, combined shear-tensile and bending dominated push-over loading. The load-displacement behaviour and crack response were captured successfully, showing the proposed methodology can be used to quantify discrete cracks on large systems, such as dam monoliths, from initiation to significant damage levels.
Citation - WoS: 16
Citation - Scopus: 20
Behavior of glulam timber beam strengthened with carbon fiber reinforced polymer strip for flexural loading
(Sage Publications Ltd, 2021) Isleyen, ummu K.; Ghoroubi, Rahim; Mercimek, Omer; Anil, Ozgur; Erdem, Recep Tugrul
In the last 20 years, the use of wooden structures and their dimensions have gradually increased. The wood application has increased in different structures such as multistory buildings, sports, industrial facilities, road and railway bridges, power transmission lines, and towers. The widespread use and size of wood structures have increased the research on developing special types of wood products supported by composite materials. Laminated wood elements are the leading composite wood materials. Laminated wooden beams allow making much larger openings than standard solid wood structural elements. The development of the sizes and usage areas of wooden structures has increased the capacity of glulam structural elements and reveals the need to improve their performance. Carbon fiber reinforced polymers (CFRPs) are the most suitable options for increasing the bearing capacity values of glulam beams and improving general load-displacement behaviors. In this study, the use of CFRP strips in different layouts to increase glulam wooden beams and the application of CFRP fan-type anchors in the CFRP strip endpoints are the studied variables. Anchored and non-anchored glulam wooden beams reinforced with CFRP strips with different layouts were tested using a three-point bending test. The ultimate load capacity, initial stiffness, displacement ductility ratio, energy dissipation capacity, failure mechanisms, and general load-displacement behavior of wooden beam test specimens were obtained and interpreted as a result of the experiments.
Citation - WoS: 6
Citation - Scopus: 6
Crack Width–Seismic Intensity Relationships for Concrete Gravity Dams
(Taylor & Francis Ltd, 2024) Soysal, Berat Feyza; Arici, Yalin; 157572
Seismic assessment of plain concrete structures like gravity dams is generally conducted based on cracking. The responses of two types of gravity dams, i.e. the conventional and roller compacted concrete (RCC), were investigated in this study using a discrete element tool coupled with special reservoir elements. Using incremental dynamic analysis, the relationship between the seismic intensity measures and crack widths on the U/S face of the monolith was obtained. The damage accumulation on conventional and RCC dams was different: The cumulative cracking on the upstream face of the monolith correlated well to a seismic intensity measure representing base shear.
Citation - WoS: 2
Citation - Scopus: 2
Critical Submergence for Single and Multiple Horizontal Intake Structures
(Springer Heidelberg, 2023) Gogus, Mustafa; Gokmener, Serkan; 6062
In this study, a series of experiments were carried out to investigate the variation of the critical submergence of air-entraining vortices with the related flow and geometric parameters at single and multiple horizontal intake structures. Three identical intake pipes were tested at a wide range of discharges with varying sidewall clearances under symmetrical and asymmetrical approach flow conditions. Experimental results indicated that increasing the number of intake structures in operation results in a more complicated flow pattern in front of the intake structures due to the mutual effects of the intakes on each other. Therefore, critical submergence values are higher for multiple intake structures than those of single water intake structures for a given Froude number. Dimensionless empirical equations were derived for each single, double and triple unit operation to calculate the critical submergence as a function of relevant flow and geometric parameters, and they were compared with the related equations available in the literature. These equations can be used to determine sufficient submergence to avoid air-entraining vortices at single and multiple horizontal intakes within the ranges of dimensionless parameters tested in this study.
Citation - WoS: 9
Citation - Scopus: 12
Debris flow modelling and hazard assessment for a glacier area: a case study in Barsem, Tajikistan
(Springer, 2023) Yilmaz, Kutay; Öztürk, Şevki; Dincer, A. Ersin; Kalpakci, Volkan; Ozturk, Sevki; 163874; İnşaat Mühendisliği
This 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.
Citation - WoS: 3
Citation - Scopus: 4
Design of Integral Spreadsheet Calculator for Engineering Applications
(Wiley, 2018) Dinckal, Cigdem; Dinçkal, Çiğdem; 26773; İnşaat Mühendisliği
Although Newton-Cotes integration formulas in engineering have been the subject of the study for a long time, the improvement in formulations is still object of interest. In this sense, design of calculators based on these formulations becomes significant. The purpose of this paper is to design an integral calculator for any engineering problems. Since the integral calculator, easy-to-understand and use, is aimed to be employed by any kind of users. Visual Basic for Applications (VBA) is the programming language of Excel. Excel spreadsheet with VBA is preferred for this purpose. In this study, a user interface input form is introduced. This form is composed of the embedded algorithm. This algorithm includes not only rules and formulations of each Newton-Cotes such as Composite Trapezoidal rule, Simpson's rules, Boole's rules, and Gauss Legendre formulations with 2, 6, 10, 16, and 24 points and exact result of any integral (if it exists) with computed true percent relative error for comparison purposes. This calculator is tested for civil, mechanical, and chemical engineering applications. The results and screenshots for each application obtained from calculator are presented. The present study allows design of an integral spreadsheet calculator for any integral given. If exact result of the integral cannot be obtainable, the calculator can perform only integral calculations numerically without exact solution and computed true percent relative error. Otherwise, user can solve the integrals completely with this tool easily and accurately again but this time by both numerically and analytically with true percent relative error calculations.
Citation - WoS: 15
Citation - Scopus: 15
Effect of anchorage number and CFRP strips length on behavior of strengthened glulam timber beam for flexural loading
(Sage Publications inc, 2021) Isleyen, Ummu Karagoz; Ghoroubi, Rahim; Mercimek, Omer; Anil, Ozgur; Togay, Abdullah; Erdem, R. Tugrul
Laminated wooden beams are more preferred in the production of wooden structures than solid timber beams because they have a higher load-carrying capacity and allow larger openings to be used in the structure. The widespread use of wooden structures and the increasing size of the structures have revealed the need for strengthened laminated wooden beams and increase their ultimate load capacity. It has become necessary to develop reinforcement details to increase the ultimate load capacity of laminated wooden beams in wooden railroads or highway bridge beams, where the traffic load increases, especially in large wooden structures, in cases where large openings must be passed. Within the horizon of the study, the behavior and performance of three-layer glulam wooden beams strengthened with anchorage and non-anchorage CFRP strips with different bonding length under flexural loading were investigated experimentally. The three-point bending test was applied to glulam timber beam test specimens produced by laminating yellow pine wood material using the polyurethane adhesive. General load-displacement behaviors, ultimate load capacity, initial stiffness, displacement ductility ratios, and energy dissipation capacities were obtained. The increase in the bonding length of the CFRP strips used for strengthening in the glulam timber beam specimens and the use of CFRP fan type anchors at the strip ends increased the ultimate load capacity and initial stiffness values of the wooden beams, as well as the displacement ductility ratios and energy dissipation capacity values.
Citation - WoS: 16
Citation - Scopus: 19
Effect of Sm on Crystallization Kinetics of Cu-Zr-Al Metallic Glasses
(Elsevier, 2020) Sikan, F.; Polat, G.; Kalay, I.; Kalay, Y. E.; 5743
The effect of Sm micro-alloying on non-isothermal and isothermal crystallization kinetics of (Zr50Cu40Al10)(100-x)Sm-x (x = 0, 2, 4 at. % Sm) alloys were investigated using differential scanning calorimetry (DSC), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Crystallization activation energies for each composition were calculated in non-isothermal conditions using Kissinger and Ozawa methods and in isothermal conditions using Johnson-Mehl-Avrami model. XRD analysis showed that crystallization product Cu10Zr7 changes to Cu2Sm with Sm presence in isothermal conditions. Both isothermal and isochronal calculations yield that the energy barrier for crystallization has increased with Sm addition. On the other hand, crystallization point drops to lower temperature at the expense of an increase in the pre-exponential factor. The Avrami exponents for all compositions were found to be below 2.5, indicating that crystallization was governed by a diffusion-controlled three-dimensional growth with a decreasing nucleation rate. The apparent increase in crystallization activation energies with increasing Sm content can be one of the affecting factors for commonly held idea of increased glass forming ability for rare-earth containing Zr-based metallic glasses.
Citation - WoS: 32
Citation - Scopus: 37
Environmental risk assessment of small hydropower (SHP) plants: A case study for Tefen SHP plant on Filyos River
(Elsevier Science Bv, 2014) Kucukali, Serhat; Küçükali, Serhat; 20413; İnşaat Mühendisliği
A multi-criteria scoring tool is used to assess the environmental risk level of small hydropower plants on the basis of documented evidence, measured data, and on-site observations. The assessment is based on evaluating compliance with the standards of the European Bank for Reconstruction and Development (EBRD). The following environmental criteria are assessed: environmental flow, water quality, fish passage and protection, watershed protection, threatened and endangered species. I evaluated the Tefen hydropower plant, which has been in operation on the Filyos River in northwestern Turkey since 2011. The assessment showed that the plant failed all of the EBRD criteria. (C) 2013 International Energy Initiative. Published by Elsevier Inc. All rights reserved.
Citation - WoS: 4
Citation - Scopus: 4
Estimation of Critical Submergence at Single Horizontal Intakes Under Asymmetric Flow Conditions
(Springer Heidelberg, 2022) Haspolat, Emre; Gogus, Mustafa; 6062
Air-entraining vortices are one of the serious hydraulic phenomena which can create various problems during the operation of intakes. Generally, air-entraining vortices start to form when the intake submergence is insufficient and less than a critical value. The purpose of the present study is to investigate the formation of air-entraining vortices and determine the critical submergences at single horizontal intake under asymmetrical approach flow conditions by conducting experiments with four different pipe diameters. In the experiments, various sidewall clearances with a series of discharges were tested for a given pipe diameter to examine the effect of dimensionless flow and geometric parameters on the critical submergence. Based on dimensional analysis, empirical equations were derived to predict critical submergence by performing regression analyses of relevant dimensionless parameters. Scale effect analysis was also carried out to investigate the effect of neglected flow parameters on the critical submergence in the application of model similitude law. A formula that makes it possible to transform model results into prototype results in the range of tested parameters was derived and compared with similar studies mostly based on existing installations. Eventually, it was pointed out that the result of the model study underestimates critical submergence compared to others due to the scale effects. Moreover, it was determined that critical submergences at intakes having asymmetrical approach flow conditions are higher than those of symmetrical approach flows.
Citation - WoS: 18
Citation - Scopus: 17
Experimental 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, Ozgur; 30604
The 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.
Citation - WoS: 9
Citation - Scopus: 12
Flow structure and fish passage performance of a brush-type fish way: A field study in the İyidere River, Turkey
(Csiro Publishing, 2019) Kucukali, Serhat; Verep, Bulent; Alp, Ahmet; Turan, Davut; Mutlu, Tanju; Kaya, Cuneyt; Ozelci, Dursun
The fish passage performance and flow structure of a brush fish pass were investigated at the ncirli Small Hydropower Plant on the yidere River, located in the East Black Sea region of Turkey. The spatial distributions of velocity vectors, power velocity, Froude number and turbulent kinetic energy are presented. The flow is quasi-uniform and subcritical, which provides different migration corridors with favourable hydraulic conditions; importantly for the fish, these corridors continue through the complete fish pass. The flow-bristle interaction creates a reduced velocity and low-turbulence resting zones. In addition, the passage efficiency of the brush fish pass was assessed using passive integrated transponder telemetry. The results clearly showed that upstream passage efficiency differs between fish species: Salmo coruhensis performed better than Alburnoides fasciatus on the same fish passage. The passage efficiency for the target fish species S. coruhensis was calculated to be 82.4%. The data revealed that the brush fish passage provides passage for small-bodied fish (total body length <15 cm) in a high-gradient channel with a slope of 10%. The monitoring data revealed that bristles as flexible hydraulic elements are beneficial for migrating fish.
Citation - WoS: 1
Citation - Scopus: 1
Hydraulics of circular bottom intake orifices
(Wiley, 2021) Gogus, Mustafa; Bulut, Muhammed; Ucar, Muhammed; 6062
In this study, the hydraulic characteristics of circular bottom intake orifices were investigated in a hydraulic model. The structure diverts the river-flow to a hydroelectric power plant through circular orifices located at the bottom of the channel. In the model, a series of circular holes of various diameters and locations at the bottom of a channel in the form of single and multiple holes were tested for different flowrates and screen angles (theta) to determine the flow diverting capacity of them. Discharges passing through orifices at known locations (x) and diameters (d) and screen slopes (theta) were measured and recorded along with the related main channel flow rates and depths (h). Using the dimensional analysis approach, an expression for the flow rate diverted from the main channel was derived as a function of related parameters, and their variations with each other were presented graphically and empirical equations were determined. Referring to the graphs and empirical equations, one can determine the discharge capacity of single and multiple intake orifices, which is important to calculate the amount of flow to be diverted from the main channel within the ranges of the related parameters used in this study.
Citation - WoS: 0
Citation - Scopus: 0
Liquefaction hazard assessment in a GIS environment: A case study of Buğday Pazarı neighborhood in Çankırı province
(Techno-press, 2024) Yurdakul, Eren; Öztürk, Şevki; Ozturk, Sevki; Sarifakioglu, Ender; 163874; İnşaat Mühendisliği
Seismic 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.
Citation - WoS: 0
Citation - Scopus: 0
Persisting challenges for performance-based building assessment
(Springer, 2014) Bayhan, B.; Kazaz, I.; Gulkan, P.
Intense research and refinement of the tools used in performance-based seismic engineering have been made, but the maturity and accuracy of these methods have not been adequately confirmed with actual data from the field. The gap between the assumed characteristics of actual building systems and their idealized counterparts used for analysis is wide. When the randomly distributed flaws in buildings as they exist in urban areas and the extreme variability of ground motion patterns combine, the conventional procedures used for pushover or dynamic response history analyses seem to fall short of reconciling the differences between calculated and observed damage. For emergency planning and loss modeling purposes, such discrepancies are factors that must be borne in mind. Two relevant examples are provided herein. These examples demonstrate that consensus-based analytical guidelines also require well-idealized building models that do not lend themselves to reasonably manageable representations from field data. As a corollary, loss modeling techniques, e.g., used for insurance purposes, must undergo further development and improvement.
Citation - WoS: 4
Citation - Scopus: 5
Predicting seismic damage on concrete gravity dams: a review
(Taylor & Francis Ltd, 2024) Arici, Yalin; Soysal, Berat Feyza; 157572
The 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.

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