İnşaat Mühendisliği Bölümü Yayın Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/395
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Article Citation - Scopus: 2On the Properties of Anisotropic Engineering Materials Based Upon Orthonormal Representations(2012) Dirxçkal, C.; Dinçkal, Çiğdem; İnşaat MühendisliğiA decomposition method[5] based upon orthonormal representations is reviewed and improved toexpress any anisotropic engineering tensor showing the effect of the material properties on the structures. A new decomposed form for the stress tensor (example for symmetric second rank tensor) different from the one available in the literature where the engineering understanding is improved, is presented. Numerical examples from different engineering materials serve to illustrate and verify the decomposition procedure. The norm concept of elastic constant tensor and norm ratios are used to study the anisotropy of these materials. It is shown that this method allows to investigate the elastic and mechanical properties of an anisotropic material possessing any material symmetry and determine anisotropy degree of that material. For a material given from an unknown symmetry, it is possible to determine its material symmetry type by this method.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.Article Citation - WoS: 5Citation - Scopus: 6Mechanical Characteristics of Environmentally Friendly Permeable Pavement: Enhanced Porous Asphalt(Jordan Univ Science & Technology, 2024) Ibis, Ahmet Bugra; Sengoz, Burak; Almusawi, Ali; Ozdemir, Derya Kaya; Topal, AliThis study explores the mechanical properties of porous -asphalt pavement, focusing on the influence of various polymers (elastomeric and reactive elastomeric terpolymers) and different aggregate compositions. Two aggregates were utilized: one is exclusively limestone -based and the other is a blend of limestone and basalt aggregates. The research findings unveiled that mixtures containing the conventional bitumen failed to meet the Cantabro loss -test criterion required for porous asphalt, necessitating a maximum threshold of 20%. In contrast, asphalt mixtures modified with polymers exhibited notably superior performance, particularly in terms of permeability, Cantabro loss and the ratio of indirect tensile strength. These results underscore the significant impact of polymer modification on enhancing the crucial mechanical properties of porous asphalt. Therefore, the study suggests the adoption of polymer -modified asphalt as a viable strategy to improve pavement longevity and overall performance, promoting its use for sustainable and durable infrastructure.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.Article Frame Finite Element Model for Nonlinear and Vibration Analysis of Steel Structures With Beam-Column and Column-Base Semi-Rigid Connections(Gazi Univ, Fac Engineering Architecture, 2022) Saritas, Afsin; Ozel, Halil FiratIn this paper, a shear deformable force-based frame finite element with semi-rigid connections is derived for nonlinear analysis of steel structures. Distributed plasticity approach is defined along element length and section depth, and linear or non-linear semi-rigid connection behavior can be specified anywhere along elements without the necessity to define additional nodes and to increase the degrees of freedom of the structural system. To perform vibration analyses with similar accuracy, force-based consistent mass matrix is used considering semi-rigidity in connections and an appropriate shear correction coefficient for I-sections. The element formulation is presented in 2 dimensions to simplify the formulation, and numerical validation and comparison studies are carried out on complex and irregular structures in 2-D and 3-D. In models with semi-rigid connections, the effect of nonlinear behavior on the structural system has been studied in both beam-column and column-bases. In the presented examples, it was possible to push structures higher than the existing displacements, and it was revealed that the nonlinear behavior in the column-base connections could create much more critical results for the structural systems with P-Delta effects. In addition, high-level accuracy results were obtained when performing vibration analyses with the application of force-based consistent mass matrix.Article Citation - WoS: 2Citation - Scopus: 3Effects of Collars on Local Scour Around Semi-Circular End Bridge Abutments(Emerald Group Publishing Ltd, 2023) Gogus, Mustafa; Daskin, Sueyla; Gokmener, SerkanThe occurrence of scour around bridge elements due to the transportation of bed material during flood events can cause serious structural damage and loss of life. Increased uncertainties in precipitation and runoff predictions due to climate change make this phenomenon more complex and dangerous. Bridge scour countermeasures should thus be more focused on decreasing scour formation around bridge elements. In this study, abutment scour under clear-water conditions with constant flow intensity was conducted and collars were tested as scour countermeasures around semi-circular end bridge abutments. The experimental study was performed in a rectangular channel with an almost uniform cohesionless bed material for 3 h with and without collars. Collars of various lengths located at different elevations around the abutments were tested to investigate the effect of collars on scour development. The results of the study showed that the scour depth decreased with increasing collar width and when the collar was placed below the bed level for a given abutment length. The results were compared with those of similar earlier studies to show the effect of abutment shape, size of the bed sediment and test durations on the development of scour depth around abutments.Article Citation - Scopus: 3Strength Prediction of Engineered Cementitious Composites With Artificial Neural Networks(MIM RESEARCH GROUP, 2021) Yesilmen, S.Engineered Cementitious composites (ECC) became widely popular in the last decade due to their superior mechanical and durability properties. Strength prediction of ECC remains an important subject since the variation of strength with age is more emphasized in these composites. In this study, mix design components and corresponding strengths of various ECC designs are obtained from the literature and ANN models were developed to predict compressive and flexural strength of ECCs. Error margins of both models were on the lower side of the reported error values in the available literature while using data with the highest variability and noise. As a result, both models claim considerable applicability in all ECC mixture types. © 2021 MIM Research Group. All rights reserved.Article Citation - WoS: 1Citation - Scopus: 1Occurrence of a Swirling Vortex Without an Intake(Gazi Univ, 2021) Yildirim, Nevzat; Tastan, KeremIn this study, mechanisms that cause the occurrence of a swirling vortex without an intake are explained. There are more than one different reasons which may cause the occurrence of an air-core vortex or a swirling-vortex flow filament within an ambient fluid. An air-core vortex or a swirling vortex flow filament can also occur in an ambient fluid media without an intake provided that the coaxial subsurface depressions and thereby the imaginary subsurface spherical sink surface sectors are hydraulically developed by any means (such as rotation of the fluid mass of spherical sector-form, impinging or penetrating jet flow, continuously entering solid body or string etc.). Although studies related to occurrence of a swirling vortex in case of an intake can be found in available literature, there are currently no studies which explains the occurrence mechanisms of a swirling vortex without an intake in detail. In this study, it is showed that the causes for the occurrence of the air-core vortex or the swirling vortex filament can be different but the main mechanism of development of the air-core vortex or the swirling vortex filament is identical for all cases.Article Citation - WoS: 1Citation - Scopus: 1Effect of Sediment Properties on Incipient Motion of Large Solitary Particles on Fixed Bed(Emerald Group Publishing Ltd, 2021) Gogus, Mustafa; Haspolat, EmreThe effect of sediment properties such as shape, size, specific weight and packing (support) condition on the incipient motion of large solitary particles was systematically investigated. A series of experiments was conducted in a rectangular tilting flume with a smooth fixed (rigid) bed under uniform flow conditions. In each experiment, a thin fibreglass rectangular rod of height 1/5 or 1.5/5 of the height of the particle was placed just downstream of the particle to imitate the interaction of particles in rivers. Contrary to common belief and knowledge, it was found that the Shields parameter decreased as the dimensionless grain diameter increased for a given bed slope under rough turbulent flow conditions. Moreover, a larger shear stress was needed to start the motion of particles on steeper slopes for a given particle diameter. An increase in the ratio of the support height to particle height by 50% resulted in an increase in the dimensionless critical shear stress by almost six times for the same particle and relative roughness.Article Effect of Downstream Expansion of a Long-Throated Flume on Flow Properties(Gazi Univ, 2021) Hatipoglu, Murat; Gogus, Mustafa; Ucar, MuhammedLong throated flumes are widely used flow measurement devices that not requiring site-specific level to flow curves and therefore laboratory experiments. In this study, downstream expansion effect of the long throated flumes with rectangular cross section were analysed for the dimensionless parameters derived from Buckingham's pi theorem and some other known hydraulic quantities such as discharge coefficient, approach velocity coefficient, submergence ratio of the flow etc. Therefore, five downstream transitions with different expansion angles were tested. In each test, the critical depth y(c), the flow head at the depth measurement section h(1), minimum required energy dissipater length L-t and the head after hydraulic jump y(2) were measured for both modular and free flow conditions. The relation of hydraulic quantities of calculated dimensionless parameters with relevant parameters; modular limits, approach velocity coefficients and discharge coefficients etc. were graphed to represent the design relationships for long throated flumes.