İnşaat Mühendisliği Bölümü Yayın Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/395

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Closure to "local Scour at Triangular Labyrinth Side Weirs Located on an Alluvial Channel" by Mustafa Tunc, Muhammet Emin Emiroglu, and Mustafa Gogus
(2023) Tunç, Mustafa; Emiroğlu, Muhammet Emin; Göğüş, Mustafa
Citation - WoS: 6
Citation - Scopus: 7
Crack Width - Seismic Intensity Relationships for Concrete Gravity Dams
(Taylor & Francis Ltd, 2024) Soysal, Berat Feyza; Arici, Yalin
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: 3
Citation - Scopus: 2
Critical Submergence for Single and Multiple Horizontal Intake Structures
(Springer Heidelberg, 2023) Gogus, Mustafa; Gokmener, Serkan
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: 4
Citation - Scopus: 4
Design of Integral Spreadsheet Calculator for Engineering Applications
(Wiley, 2018) Dinckal, Cigdem
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: 22
Citation - Scopus: 22
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: 17
Citation - Scopus: 20
Effect of Sm on Crystallization Kinetics of Cu-Zr Metallic Glasses
(Elsevier, 2020) Sikan, F.; Polat, G.; Kalay, I.; Kalay, Y. E.
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.
Effect of the Bed-Sediment Layer on the Scour Caused by a Jet
(2016) Taştan, Kerem; Koçak, Peli̇n Pınar; Yıldırım, Nevzat
Scour caused by a water jet impinging the bedsediment layer is a significant concern for hydraulic engineers. Although several studies investigated the maximum scour depth on the non-cohesive bed-sediment layer, the effect of the bed-sediment layer’s thickness on the scour was not studied. This study investigated the effect of the thickness of the non-cohesive sediment layer at the canal bed on the depth of the scour caused by a water jet. The dimensionless parameters affecting the depth of the scour were obtained via dimensional analysis. Experiments were conducted on two different, non-cohesive bed-sediment layers at the bottom of a rectangular canal for different jet Froude numbers. Experimental results indicated that the depth of the scour increases with the thickness of the bed-sediment layer; this is because as the thickness of the sediment layer increases, the penetration depth of the air bubbles (dragged and enforced by the impinging water jet) through the sediment layer just under the scour hole increases. Due to the buoyancy force, as the air bubbles rise upward, they apply uplift forces and dynamic effects onto sediment particles, dislodging, suspending, and carrying the sediment particles away from the bed. If the thickness of the sediment layer is increased beyond a limiting value for a given flow condition, the maximum depth of the scour does not change (it remains almost constant). The effect of the thickness of the bed-sediment layer on the depth of the scour is present but not excessively large.
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
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
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: 14
Citation - Scopus: 15
Experimental and Numerical Investigation of Rc Column Strengthening With Cfrp Strips Subjected To Low-Velocity Impact Load
(Techno-press, 2021) Mercimek, Omer; Anil, Ozgur; Ghoroubi, Rahim; Sakin, Shaimaa; Yilmaz, Tolga
Reinforced concrete (RC) square columns are vulnerable to sudden dynamic impact loadings such as the vehicle crash to the bridges of highway or seaway, rock fall, the collision of masses with the effect of flood and landslide. In this experimental study RC square columns strengthened with and without CFRP strip subjected to sudden low velocity lateral impact loading were investigated. Drop-hammer testing machine was used to apply the impact loading to RC square columns. The test specimens were manufactured with square cross sections with 1/3 geometric scale. In scope of the study, 6 test specimens were manufactured and tested. The main variables considered in the study were the application point of impact loading, and CFRP strip spacing. A 9.0 kg mass was allowed to fall freely from a height of 1.0 m to apply the impact loading on the columns. During the impact tests, accelerations, impact force, column mid-point displacements and CFRP strip strains measurements were taken. The general behavior of test specimens, collapse mechanisms, acceleration, displacement, impact load and strain time relationships were interpreted, and the load displacement relationships were obtained. The data from the experimental study was used to investigate the effect of variables on the impact performances of RC columns. It has been observed that the strengthening method applied to reinforced concrete columns, which are designed with insufficient shear strength, insufficient shear reinforcement and produced with low strength concrete, using CFRP strips significantly improves the behavior of the columns under the effect of sudden dynamic impact loading and increases their performance. As a result of the increase in the hardness and rigidity of the specimens strengthened by wrapping with CFRP strips, the accelerations due to the impact loading increased, the displacements decreased and the number of shear cracks formed decreased and the damage was limited. Moreover, the finite element analyses of tested specimens were performed using ABAQUS software to further investigate the impact behavior.
High-velocity impact of large caliber tungsten projectiles on ordinary Portland and calcium aluminate cement based HPSFRC and SIFCON slabs. Part I: experimental investigations
(Techno-Press, 2011) Polat, Gülkan; Korucu, Hasan
Impact experiments have been carried out on concrete slabs. The first group was traditionally manufactured, densely reinforced concrete targets, and the next were ordinary Portland and calcium aluminate cement based HPSFRC (High performance steel fiber reinforced concrete) and SIFCON (Slurry infiltrated concrete) targets. All specimens were hit by anti-armor tungsten projectiles at a muzzle velocity of over 4 Mach causing destructive perforation. In Part I of this article, production and experimental procedures are described. The first group of specimens were ordinary CEM I 42.5 R cement based targets including only dense reinforcement. In the second and third groups, specimens were produced using CEM I 42.5 R cement and Calcium Aluminate Cement (CAC40) with ordinary reinforcement and steel fibers 2 percent in volume. In the fourth group, SIFCON specimens including 12 percent of steel fibers without reinforcement were tested. A high-speed camera was used to capture impact and residual velocities of the projectile. Sample tests were performed to obtain mechanical properties of the materials. In the companion Part II of this study, numerical investigations and simulations performed will be presented. Few studies exist that examine high-velocity impact effects on CAC40 based HPSFRC targets, so this investigation gives an insight for comparison of their behavior with Portland cement based and SIFCON specimens
Citation - WoS: 1
Citation - Scopus: 2
Hydraulics of Circular Bottom Intake Orifices
(Wiley, 2021) Gogus, Mustafa; Bulut, Muhammed; Ucar, Muhammed
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.
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, Eren
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: 16
Citation - Scopus: 16
Novel Bond-Slip Model Between Concrete and Angular Cfrp Fan Type Anchoraged Cfrp Strip
(Taylor & Francis Ltd, 2022) Ghoroubi, Rahim; Mercimek, Omer; Sakin, Shaimaa; Anil, Ozgur
One of the most important design approaches in the repairing/strengthening details is using CFRP (Carbon Fiber Reinforced Polymer) to delay the debonding of the CFRP strips/plates from the surface to take full advantage of the CFRP reinforcement. Compared to non-anchored strips, research studies regarding bond-slip models developed for fan type CFRP anchors and anchored CFRP strips to strengthen details are limited in the related literature review. However, in studies on this subject, anchors are placed at 90 degrees to the axial tensile force applied to the CFRP strips. The ultimate load-bearing capacity and bond-slip models of CFRP strips with the different angled CFRP fan type anchor under axial tensile force have not been found in the literature review. Within the study's scope, 28 angled CFRP strip test specimens were produced and then tested under the effect of monotonically increasing axial tensile force with an experimental setup designed by the authors. The variables examined in this study were the concrete compressive power, the CFRP strip's width, the number of the CFRP anchor fan type, and the angle of the anchor placed on the CFRP strip. As a result of the study, an equation was proposed for calculating the ultimate load-bearing capacity of angled anchored CFRP strips and angled anchored CFRP strips. Finally, a new proposal for the bond-slip model was developed. It is thought that the new interface bond-slip model developed for CFRP strips with different angles will make an important contribution to the literature. It can be used in finite element analysis to realistically analyze the capacities and load-displacement behavior of reinforced concrete structural elements by strengthening such strips.
Citation - WoS: 3
Citation - Scopus: 3
Numerical and Experimental Modelling of Flow at Tyrolean Weirs
(Elsevier Sci Ltd, 2021) Yildiz, Ali; Marti, Ali Ihsan; Gogus, Mustafa
In this study, a small-scaled Tyrolean weir model was constructed in the laboratory environment and a series of experiments were conducted on it, for two different rack inclinations (theta(1) = 18 degrees and theta(2) = 25 degrees) and three different bar spacings (e(1) = 3 mm, e(2) = 6 mm and e(3) = 10 mm) for a range of upstream flow discharges. The flow rates passing through the racks and going downstream over the racks were measured. Empirical equations for the discharge coefficient and water capture capacity of the Tyrolean weirs were determined by applying dimensional analysis to the parameters involved in the phenomenon. The related dimensionless parameters were presented with graphs and empirical equations for discharge coefficients were derived, coefficient of determination R-2 of equations for theta(1) = 18 degrees and theta(2) = 25 degrees are found 0.838 and 0.825 respectively. According to results obtained from experimental data, C-d increases as the Froude number ((F-r)(e)) between bars increases and water capture capacity [(q(w))(i)/(q(w))(T)] of the racks decreases with increasing ((F-r)(e)). Also, a numerical model of the Tyrolean weir was generated by using Flow-3D software and it was shown that the results of the numerical analysis were very consistent with the physical model results at large bar spacing such as e = 10 mm. As the bar spacing (e) reduces, the success of the numerical model giving consistent results with physical model is decreasing.
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: 9
Citation - Scopus: 7
Predicting Seismic Damage on Concrete Gravity Dams: a Review
(Taylor & Francis Ltd, 2024) Arici, Yalin; Soysal, Berat Feyza
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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