İnşaat Mühendisliği Bölümü Yayın Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/395
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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 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: 12Citation - Scopus: 16A Metaheuristic-Guided Machine Learning Approach for Concrete Strength Prediction With High Mix Design Variability Using Ultrasonic Pulse Velocity Data(Elsevier, 2023) Selcuk, S.; Tang, P.Assessment of concrete strength in existing structures is a common engineering problem. Several attempts in the literature showed the potential of ML methods for predicting concrete strength using concrete properties and NDT values as inputs. However, almost all such ML efforts based on NDT data trained models to predict concrete strength for a specific concrete mix design. We trained a global ML-based model that can predict concrete strength for a wide range of concrete types. This study uses data with high variability for training a metaheuristic-guided ANN model that can cover most concrete mixes used in practice. We put together a dataset that has large variations of mix design components. Training an ANN model using this dataset introduced significant test errors as expected. We optimized hyperparameters, architecture of the ANN model and performed feature selection using genetic algorithm. The proposed model reduces test errors from 9.3 MPa to 4.8 MPa.Article 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.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 Exact Forecasting for Covid-19 Data: Case Study for Turkey(World Scientific Publ Co Pte Ltd, 2021) Dinckal, CigdemThe novel coronavirus COVID-19 (SARS-CoV-2) with the first clinical case emerged in the city of Wuhan in China in December 2019. Then it has spread to the entire world in very short time and turned into a global problem, namely, it has rapidly become a pandemic. Within this context, many studies have attempted to predict the consequences of the pandemic in certain countries. Nevertheless, these studies have focused on some parameters such as reproductive number, recovery rate and mortality rate when performing forecasting. This study aims to forecast COVID-19 data in Turkey with use of a new technique which is a combination of classical exponential smoothing and moving average. There is no need for reproductive number, recovery rate and mortality rate computation in this proposed technique. Simulations are carried out for the number of daily cases, active cases (those are cases with no symptoms), daily tests, recovering patients, patients in the intensive care unit, daily intubated patients, and deaths forecasting and results are tested on Mean Absolute Percentage Error (MAPE) criterion. It is shown that this technique captured the system dynamic behavior in Turkey and made exact predictions with the use of real time dataset.Article Citation - WoS: 6Citation - Scopus: 6Estimation of Critical Submergence at Single Horizontal Intakes Under Asymmetric Flow Conditions(Springer Heidelberg, 2022) Haspolat, Emre; Gogus, MustafaAir-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.