Civil Engineering / İnşaat Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/13
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Article Closure To "reverse Flood Routing in Rivers Using Linear and Nonlinear Muskingum Models" by Meisam Badfar, Reza Barati, Emrah Dogan, and Gokmen Tayfur(American Society of Civil Engineers (ASCE), 2022) Badfar, Meisam; Barati, Reza; Doğan, Emrah; Tayfur, GökmenConference Object Physical Model Experiments of Ordu-Giresun Airport, Turkey(American Society of Civil Engineers (ASCE), 2016) Arıkan, S. E.; Gültekin, N.; Küçükosmanoğlu, A.; Özbahçeci, Bergüzar; Sağ, M.; Kılıç, Y.; Koca, F.Ordu-Giresun Airport, which has been constructed recently, being an example of the aviation sector of Turkish transportation network, is a project having marine structural aspects due to the construction at the sea by filling and in this workout physical model experiments of the project are evaluated. 3000-meters-long runway and the other superstructures of the airport, the first example of construction of such a structure by filling in the sea in Turkey, is to be protected by a breakwater of 7435 meters long. 'First Cross Section' has been prepared by using experimental formulas and artificial neural network and 'Second Cross Section', being the alternative of the first one has been planned. Yet, both cross sections have similar characteristics, they have berm heights in such a manner that 'First Cross Section' enables the structure to be constructed from the sea, whereas 'Second Cross Section' makes it possible from the land. Both cross sections are aimed to be evaluated in terms of stability, wave overtopping and economy through the hydraulic model studies performed at the Hydraulics Laboratory of Turkish Ministry of Transportation, Maritime Affairs and Communication. Starting from design stage (computation of design wave characteristics, physical model experiment under different wave conditions on different structure alternatives) to construction stage the engineering studies is presented with comparisons and discussions.Conference Object Citation - Scopus: 1A New Approach To Breakwater Design-2b Block(American Society of Civil Engineers (ASCE), 2016) Bilyay, Engin; Özbahçeci, Bergüzar; Bacanlı, Selahattin; Kızıroğlu, GülşenBreakwaters are one of the oldest and important marine structures. Rubble mound breakwater is a very common type in all around the world. If the heavier rock is necessary for the design, concrete armor units are used. Each unit has its own advantages and disadvantages. For example cube and antifer blocks are massive units and their interlocking is weak. Dolos and tribar units have good interlocking but rocking stresses in these units are extraordinarily high. The placement method is very important and requires special equipment and experienced staff for the later developed single-layered units like accropod and core-loc. Moreover, continuous touching of blocks to each other and fatigue of the material may cause the breakdown of legs and serious damage of armor layer. And in case of damage, it is necessary to remove the units in a wide area on the breakwater and then relocate them, so it is very difficult to repair. A new type concrete armor unit is developed considering all these problems. It is called 2B Blocks.Conference Object An Integrated Assessment of Water Quality in an Arsenic Containing Aquifer: Milestones From Hydrogeology To Public Health(American Society of Civil Engineers (ASCE), 2012) Gündüz, Orhan; Şimşek, Celalettin; Elçi, Alper; Baba, Alper; Bakar, Çoşkun; Gürleyük, Hakan; Çakır, A.; Mutlu, MerdiyeA multi-disciplinary research is being conducted in Simav Plain, Turkey where an arsenic containing aquifer is at the center of attention. The study is not only aimed to understand the sources and mechanisms of the presence of high arsenic levels in groundwater but also to determine the associated consequences with regards to human health. The high arsenic levels in most groundwater (N=33, avg. 162 ppb), surface water (N=9, avg. 76.6 ppb) and geothermal water (N=3, avg. 406 ppb) samples are strongly related to high occurrences of arsenic in rocks and soils of the plain, which range between 7.1 and 833.9 ppm with an average of 49 ppm. These values correspond to several orders of magnitude higher than international standards and world averages in water and soil, respectively. With this motivation, this research also focuses on human health in the study area associated with exposure to these high arsenic levels via numerous pathways. Consequently, more than 1000 individuals were personally surveyed by public health specialists to determine an inventory of diseases in the area. Furthermore, a verbal autopsy study was also conducted with relatives of the deceased, which were further verified with hospital records, to understand the underlying death cause. As a result, certain cancer rates were found to exceed national averages and the results statistically demonstrated a potential link with high arsenic levels mainly through oral exposure.Conference Object The Use of Cokriging Algorithm for Arsenic Mapping in Groundwater Systems(American Society of Civil Engineers (ASCE), 2012) Gündüz, Orhan; Elçi, Alper; Şimşek, Celalettin; Baba, AlperAccurate mapping of the spatial distribution of arsenic in groundwater is an important but equally difficult task to complete due to a number of uncertainties. Classical univariate interpolation algorithms could sometimes be insufficient to capture high concentration and high gradient areas. Under these circumstances, the use of an auxiliary parameter could provide better estimates of arsenic distribution. Based on this premise, arsenic cokriging with a correlated parameter can improve the performance of interpolation and can enhance the quality of predictions. In order to test this hypothesis, a water quality dataset from an arsenic containing aquifer in Simav Plain, Turkey is used to develop arsenic distribution maps. Arsenic is cokriged with correlated parameters such as manganese, iron and dissolved oxygen; and the results are compared with univariate interpolation algorithms such as ordinary kriging and inverse distance weighing. The comparisons were performed with cross validation at sampling locations and assessed based on mean and root mean squared errors. The results revealed that maps developed using arsenic cokriging with iron have given the smallest error value and have shown closest fit to the extreme values in the dataset. Accordingly, arsenic cokriging with iron is believed to be a promising approach in mapping arsenic distributions in groundwater.Article Citation - WoS: 4Citation - Scopus: 5Importance of Static Correction and Damping in the Analysis of a Cable-Stayed Bridge Subjected To Displacement Loading(American Society of Civil Engineers (ASCE), 2017) Hızal, Çağlayan; Turan, GürsoyCable-stayed bridges with long spans are excited by different support vibrations on both sides of the main span. Therefore, a realistic seismic structural analysis of the bridge must involve multiple-support excitation. The dynamic equation of motion, in which all degrees of freedom are solved at once, can be solved directly. A modal analysis might also be possible, but care must be taken with the number of modes used in the analysis. If the ground motion is described in terms of displacement and velocity, which is referred to as displacement loading, then a static correction that will account for the unconsidered higher modes must be performed. In this study, the procedure of multiple-support excitation through the use of modal transformation is explained in detail. The effects of changes in damping levels that affect the analysis results are investigated by using the static correction method in displacement loading. An example is given to illustrate the mentioned problem by using a finite-element model of the cable-stayed Bill Emerson Memorial Bridge.Article Citation - WoS: 1Citation - Scopus: 3Strength Requirements for Shear Diaphragms Used for Stability Bracing of Steel Beams(American Society of Civil Engineers (ASCE), 2017) Eğilmez, Oğuz Özgür; Vardaroğlu, Mustafa; Akbaba, AndaçLight-gauge metal sheeting is often used in steel building and bridge industries as concrete deck formwork. Besides providing support to the fresh concrete, the sheeting acts as a shear diaphragm and provides continuous lateral bracing to the top flanges of the beams to which they are attached. An adequate stability-bracing system must possess sufficient stiffness and strength to control deformations and brace forces. Strength requirements for shear diaphragms are currently not well established. A computational study was conducted to develop strength requirements for shear diaphragms bracing simply supported steel beams. Both end-fastener and sidelap-fastener connections were modeled in the study. To the best of the authors' knowledge, this is the first study to quantify the stability-induced forces in sidelap fasteners. The effects of deck width and number of end and sidelap fasteners on brace forces were investigated. Expressions were developed to estimate the stability-induced brace forces in end-fastener and sidelap-fastener connections.Article Citation - WoS: 46Citation - Scopus: 53Distorted Physical Model To Study Sudden Partial Dam Break Flows in an Urban Area(American Society of Civil Engineers (ASCE), 2014) Güney, Mehmet Şükrü; Tayfur, Gökmen; Bombar, Gökçen; Elçi, ŞebnemA distorted physical model, based on Ürkmez Dam in Izmir, Turkey, was built to study sudden partial dam break flows. The distorted model had a horizontal scale of 1/150 and a vertical scale of 1/30, containing dam reservoir, dam body, and downstream area-from dam body to Ürkmez urban area until the sea coast. In the model, the reservoir is approximately 12 m3, the dam body has a width of 2.84 m and a height of 1.07 m, and the downstream area is nearly 200 m2. The Ürkmez Dam was chosen because Ürkmez Town is located right at its downstream area, allowing the study of dam break flows in an urban area. Furthermore, the dimensions were suitable such that it allowed the construction of a physical model (dam reservoir, dam body, and downstream area) having a horizontal scale of 1/150 in the available space of 300 m2. The features creating roughness such as buildings, bridge, and roads were also reflected in the physical model. The dam break flow was investigated for sudden partial collapse, which was simulated by a trapezoidal breach on the dam body. The water depths at downstream area were measured at eight different locations by using e+ WATER L (level) sensors. The velocities were measured at four different locations by ultrasonic velocity profiler (UVP) transducers. The propagation of the flood was recorded by a high-defnition camera. The experimental results show that the Ürkmez area can be flooded in a matter of minutes, at depths reaching up to 3 m in residential areas in 4 min. The flood wave front can reach the residential areas in 2 min and to the sea coast in 4 min. Flow velocities can reach 70.9 km/h in sparse residential areas, close to dam body. Away from the dam body in the sparse buildings part of the town, the velocities can reach 27.7 km/h. In dense residential areas of the town, the velocities are too low (2.8 km/h) but flow depths can reach 3 m. Velocity profiles show similar behavior like unsteady and nonuniform open channel flow in nonresidential areas close to the dam body. In residential areas away from the dam body, the velocity profiles are more uniform, having lower velocity values. Vertical variations of velocities show markedly different behavior during rising and recession stages. The profiles are smooth during the rising stage in sparse residential area, yet it shows fluctuating behavior during the recession stage.Article Citation - WoS: 54Citation - Scopus: 69Strength Prediction of High-Strength Concrete by Fuzzy Logic and Artificial Neural Networks(American Society of Civil Engineers (ASCE), 2014) Tayfur, Gökmen; Erdem, Tahir Kemal; Kırca, ÖnderHigh-strength concretes (HSC) were prepared with five different binder contents, each of which had several silica fume (SF) ratios (0-15%). The compressive strength was determined at 3, 7, and 28 days, resulting in a total of 60 sets of data. In a fuzzy logic (FL) algorithm, three input variables (SF content, binder content, and age) and the output variable (compressive strength) were fuzzified using triangular membership functions. A total of 24 fuzzy rules were inferred from 60% of the data. Moreover, the FL model was tested against an artificial neural networks (ANNs) model. The results show that FL can successfully be applied to predict the compressive strength of HSC. Three input variables were sufficient to obtain accurate results. The operators used in constructing the FL model were found to be appropriate for compressive strength prediction. The performance of FL was comparable to that of ANN. The extrapolation capability of FL and ANNs were found to be satisfactory.Article Citation - WoS: 14Citation - Scopus: 14Seismic Performance of Wide-Beam Infill-Joist Block Rc Frames in Turkey(American Society of Civil Engineers (ASCE), 2015) Dönmez, CemalettinObservations after the 2011 Van-Erciş earthquake show that some of the recently constructed reinforced-concrete buildings were either heavily damaged or had collapsed. As a building subtype, wide-beam, infill-joist block reinforced-concrete frames got attention because of their mode of failure. There were several such buildings that failed in strong-column, weak-beam mode. Considering the demand created by the earthquake, structures were not expected to reach their full capacity. The purpose of this study is to review the history and current practice of infill-joist frames in Turkey and to conduct a performance evaluation of infill-joist frames designed per the current earthquake code (2007). Regulations for this building subtype are critically reviewed, and the designer's response to code regulations is discussed. Results indicate that the force-based design approach used in the current code is not always adequate to satisfy the displacement demands. In addition, it is observed that layout, proportioning, and detailing requirements of beam-end regions and beam-column connections do not always warrant ductile behavior as targeted.