Browsing by Author "Erdil, Baris"

Now showing 1 - 16 of 16

Cfrp-Confined Concrete Columns Under Different Environmental Conditions
(Ice Publishing, 2013) Erdil, Baris; Akyuz, Ugurhan; Yaman, Ismail Ozgur
The behaviour of carbon fibre reinforced polymer-confined cylindrical and prismatic concrete specimens subjected to several different environmental conditions was investigated in four groups. The first group of specimens was used as a reference. In the second group, specimens were exposed to dry heating-cooling (H-C) cycles in the environmental test chamber (ETC), whereas specimens in the third group were kept in water while simultaneously being subjected to H-C cycles in the ETC. Finally, the last group of specimens was kept outside of the laboratory to determine the outdoor environmental effect. After the ageing phase, specimens were tested under monotonic uniaxial loading to determine the change in their mechanical properties. Cylindrical specimens were observed not to be significantly affected by H-C cycles with the exception of their ultimate strain, which decreased under outdoor conditions. As for the prismatic specimens, dry H-C cycles were found to reduce strength by up to 24% and strain by up to 33%. Wet H-C cycles and outdoor exposure were seen to decrease further the strength and ultimate strain of prismatic specimens.
Confinement Effectiveness of Cfrp in Axial Members Under Various Loading Conditions
(Trans Tech Publications Ltd, 2013) Erdil, Baris; Akyuz, Ugurhan; Yaman, Ismail Ozgur
In this study, parameters affecting the mechanical properties of FRP-confined cylindrical and prismatic concrete columns were studied via experimental data, which were collected after an extensive literature review. The parameters were summarized as unconfined concrete strength, FRP thickness, cylinder diameter, overlap length of FRP, sustained stress level, heating-cooling effect and corner radius in prismatic specimens. Considering these parameters the confinement effectiveness is established analytically in the light of ultimate strength values obtained from the test results available in the literature. No steel reinforcement is taken into account because the main aim is to capture the behavior of FRP-confinement only. The analytical results revealed that unconfined concrete strength, FRP thickness, cross-sectional dimension of the specimen are the main parameters controlling the confinement effectiveness in cylindrical specimens. In addition to these parameters corner radius and sustained stress level are found to be significant in prismatic specimens.
Critical Cold Joint Angle in Concrete
(Elsevier Sci Ltd, 2023) Ali, Quraish Qusay; Erdil, Baris; Jassam, Taha Mohammed
This study aims to understand the effect of different cold joint angles on splitting tensile and compressive strength of concrete. A series of tests were conducted in the context of this study. Four different concrete grades (10, 20, 25, 30 MPa) were selected to demonstrate the very low grade, low grade, minimum grade and normal grades of concretes according to Turkish Earthquake Codes 2007 and 2018. In addition to the concrete grades, cold joint angle is also a parameter to be investigated. Zero angle was the control angle. Besides, 20, 45, 65 and 90 degrees were studied to understand the effect of cold joint angle on tensile and compressive strength of the concrete. It was found that compressive strength was not adversely affected from the cold joint angles of 0 degrees, 20 degrees, 45 degrees and 90 degrees. The difference is almost 10 %. However, 65 degrees of cold joint angle seems to affect the compressive strength significantly since the reduction in compressive strength varied between 32.5 % and 48.4 %. Specimens having 65 degrees cold joint angle was observed to fail by sliding over the cold joint plane. Splitting tensile tests showed that 90 degrees cold joint angle was the most unfavorable situation. Introducing vertical cracks parallel to the loading direction before the test resulted in the lowest tensile strengths. Splitting tensile strength equation considering the cold joint angles was proposed.
A Detailed Comparison of Preliminary Seismic Vulnerability Assessment Methods for Rc Buildings
(Springer international Publishing Ag, 2019) Erdil, Baris; Ceylan, Harun
Tier 2 (preliminary) evaluation methods seem to be efficient in determining seismic vulnerability of buildings in large building stocks because they can be used to determine the seismic performance of a single building when compared to Tier 1 evaluation methods (street survey). Besides, they require less time as opposed to detailed evaluation methods (Tier 3). Eleven preliminary vulnerability analysis procedures are compared considering the data of 192 buildings experienced either 2011 Van Earthquakes, 2003 Bingol Earthquake or 2002 Afyon Earthquake. Comparisons are made in terms of the number of parameters, influence of parameters on final seismic score, weighing factors of the parameters, the success rate of predicting the seismic performance of the examined buildings. Investigated procedures use at least four parameters and at most 22 parameters. Although number of stories have adverse effect on the seismic performance, concrete strength, area of shear walls and columns seem to have positive effect. Among the main parameters used in all procedures, area of shear walls is found to be the most influential parameter; however, concrete strength is one of the least effective parameters. As for the rate of correct vulnerability estimate of the 192 buildings, it is found that the best prediction rate belongs to Sucuoglu and Yazgan (in Wasti and Ozcebe (eds) Seismic assessment and rehabilitation of existing buildings, NATO science series (series IV: earth and environmental sciences), Kluwer Academic Publishers, London, 2003) with 79.2%. All the procedures except Ozcebe et al. (in Wasti and Ozcebe (eds) Seismic assessment and rehabilitation of existing buildings, NATO science series (series IV: earth and environmental sciences), Kluwer Academic Publishers, London, 2003) have correct estimate rate equal to or higher than 63%.
Effect of Adobe Wall Shapes and Openings on Out-Of Behavior
(Elsevier Science inc, 2025) Kipcak, Firat; Erdil, Baris
Adobe masonry structures which are among the traditional structures, are affected by many parameters like other masonry structures. These parameters include material, workmanship, mortar, support condition, wall direction, wall slenderness and opening properties. Those parameters are important because they affect the seismic performance significantly. There are many studies in the literature considering the in-plane behavior of masonry walls; however, it has been observed after many earthquakes that most of the adobe walls collapse due to out-of-plane displacements. In order to understand the out-of-plane behavior well, this study aims to experimentally and numerically investigate the out-of-plane behavior of adobe walls having different configurations such as wall aspect ratio, wall shape and openings. The failure mechanisms, horizontal load capacity ratios and failure profiles were evaluated. In the study, a total of 18 different wall models were produced: 6 U-shaped walls with two-side support walls, 6 L-shaped walls with one-side support walls and 6 I-shaped walls without support walls. All the walls were tested on a tilting table. They were also analyzed by simplified micro modeling technique in ABAQUS software. The adobe walls were constructed in the form of interlocking pattern according to the traditional pattern. A clay and fiber mixed mortar with the same properties as the unit was used between the adobe units. According to the experimental and numerical results, it was observed that the support walls in adobe walls increased the out-of-plane wall stiffness and lateral load capacity ratio. As the wall aspect ratio increased, the lateral load capacity decreased in the models with support walls and increased in the models without support walls. Increasing wall length decreased the effectiveness of the supporting wall. Door/window openings left in the wall did not adversely affect the capacity to a great extent. The lateral load capacity/weight ratio changed slightly due to the weight reduction of the openings. The capacities and failure mechanisms obtained from the experimental and numerical studies were found to be similar.
The Effect of Voids on Flexural Capacity of Reinforced Concrete Slabs
(Budapest Univ Technology Economics, 2023) Kipcak, Firat; Erdil, Baris; Tapan, Mucip; Karasin, Abdulhalim
The voided reinforced concrete slab system is mainly produced with polyester foam placed mostly at the bottom of the slab. The aim of the voids is to reduce the weight of the slab. In this paper behavior of the voided reinforced concrete slabs in which voids placed at the mid-height of the slab cross-section, is examined analytically. A series of models were created to come up with a lightweight slab. Two distinct slab models were analyzed using the ABAQUS software. In the first group, slabs had three layers, in which bottom and top layers were of solid reinforced concrete, but the mid layer was of voided unreinforced concrete. In the second layer, in order to increase the contact between top and bottom layers of the slab, crossties were utilized, and the mid layer was reinforced accordingly. Since all the layers were 5 cm thick, the total thickness of the slabs were 15 cm. Slabs were 100 cm wide and 200 cm long. They were simulated the three-point bending test. Concrete damaged plasticity material model (CDPM) for concrete and elastoplastic material model for steel was selected. From the results it was found that moment capacity decreased with the increase in the volume of the voids. There was a sudden decrease in strength after reaching the yield strength in voided slab without a crosstie. In addition, crossties enabled the reduction of the weight of the slabs without significant decrease in moment capacity.
Effects of Structural Parameters on Seismic Behaviour of Historical Masonry Minaret
(Budapest Univ Technology Economics, 2018) Erdil, Baris; Tapan, Mucip; Akkaya, Ismail; Korkut, Fuat
The October 23, 2011 (M-w = 7.2) and November 9, 2011 (M-w = 5.6) earthquakes increased the damage in the minaret of Van Ulu Mosque, an important historical masonry structure built with solid bricks in Eastern Turkey, resulting in significant shear cracks. It was found that since the door and window openings are not symmetrically placed, they result in unsymmetrical stiffness distribution. The contribution of staircase and the core on stiffness is ignorable but its effect on the mass is significant. The pulpit with chamfered corner results in unsymmetrical transverse displacements. Brace wall improves the stiffness however contributes to the unsymmetrical behaviour considerably. The reason for the diagonal cracks can be attributed to the unsymmetrical brace wall and the chamfered pulpit but the effect of brace wall is more pronounced. After introducing the cracks, a new model was created and calibrated according to the results of Operational Modal Analysis. Diagonal cracks were found to be likely to develop under earthquake loading. Drifts are observed to increase significantly upon the introduction of the cracks.
Evaluation of Successful Seismic Bridge Design Practice in Turkey
(Asce-amer Soc Civil Engineers, 2014) Okuyucu, Dilek; Kale, Ozkan; Erdil, Baris; Caner, Alp; Askan, Aysegul; Akansel, Vesile Hatun
On October 23, 2011, a destructive earthquake of Mw=7.1 occurred in Eastern Turkey. The event occurred on a previously unknown fault with a thrust mechanism and resulted in 604 deaths and major structural damage to the buildings. The highways at the Van earthquake zone were open to service of rescue operations, aid trucks, and regular traffic immediately after the devastating event. As a success story, the bridges closer to the fault line than the towns of Van and Erci were observed to have minimal damage, such as minor support movements and cracks at the shear keys. Among the 14 highway bridges in the region evaluated by the authors, only two adjacent bridges, Bendimahi-II, had minor structural cracking along the column height. As expected, the bridges of concern were observed to perform in the essentially elastic state. The main focus of this study was to evaluate the seismic bridge design practice in Turkey, which resulted in a successful seismic performance of the earthquake-zone bridges. As an illustrative example, Bendimahi-II bridge, the closest one to the fault line, was studied through an analytical investigation.
Experimental Evaluation of Rigidity Center
(Mdpi, 2023) Korkut, Fuat; Aksoy, Enes; Erdil, Baris
It is known that when a reinforced concrete building exposed to a horizontal load is subjected to torsional moments around its center of rigidity, additional shear stresses occur in the vertical load-carrying elements, such as the columns and shear walls. Therefore, in order to estimate the additional stresses caused by the torsion, the rigidity center should be calculated precisely. It is known that there are several analytical approaches to calculating the rigidity center location. These approaches do not calculate the rigidity centers close to each other in asymmetric buildings. As significant differences were observed in the calculation of the rigidity center using analytical methods, it was decided to seek verification by conducting an experimental study. In order to calculate and verify the location of the rigidity center, an extensive experimental study was planned. A total of 20 scaled and revised buildings were built, and they were tested in the specially designed test setup. The tested buildings had square, rectangular and irregular floor plans. In addition, vertical load-carrying members were either symmetrically placed on the floor plan or kept asymmetrical to see the effect of their location on the rigidity center. All the buildings were tested under their self-weight, and the corresponding displacements were recorded. Additionally, all the buildings were modeled using ETABS to verify the theoretical background of the rigidity center. From the test results, it was found that the resultant shear force can be calculated by multiplying the displacements of each member of a given story found from the tests on its bending stiffness, and this will give the location of the rigidity center. The rigidity center was found to be identical to the results obtained from the 3D model analysis using ETABS, although it uses a different procedure. As the results from the experiment and 3D model are close to each other, it can be said that the rigidity center of reinforced concrete buildings can be found from simple tests using any material that has almost uniform mechanical properties.
Mvp Interaction Based Seismic Vulnerability Assessment of Rc Buildings
(Croatian Soc Civil Engineers-hsgi, 2019) Erdil, Baris; Ceylan, Harun
Consuming less time as compared to detailed evaluation techniques, preliminary seismic vulnerability assessments are widely utilized worldwide. In this paper, a new procedure called MVP Method (moment (M), shear (V) and axial (P)), is proposed to evaluate seismic performance of RC buildings. The procedure needs structural and architectural parameters and considers the interaction of moment, shear, and axial load capacities and demands. Simple equations are proposed for each capacity and demand so as to calculate the building performance score. The proposed procedure was verified on 192 buildings, and the success rate ranged from 86.5 to 89.1 %.
Out-Of Behavior of Dry-Stack Brick Masonry Walls
(Wiley, 2024) Erdil, Baris; Kipcak, Firat; Tapan, Muecip
As a result of the combination of the complex behavior of masonry buildings with insufficient material quality and lack in engineering calculations, a large number of damages has been observed in the earthquakes that occurred in recent years. Therefore, a realistic understanding of the behavior of masonry walls and buildings is necessary to construct seismic-resistant structures. Since masonry walls have many variables, performing experiments in which each variable is present at the same time will make it difficult to understand the behavior. For these reasons, considering the out-of-plane failures that are frequently mentioned in recent earthquakes, in this study, variables in dry-stack brick masonry buildings such as the aspect ratio of the wall (2, 1.33, and 1), the presence of the transverse walls (2, 1, and 0), and the openings in the walls (door and/or window) were taken into account separately. Eighteen different wall configurations were designed, and a total of 48 dry-stack walls having U-shape, L-shape, and I-shape in plan were tested by a specially constructed tilting table setup to determine their out-of-plane behavior. From the test results, it was found that lateral load capacity of the U-shaped walls without openings increased as the aspect ratio (L/H) decreased. No change in capacity was observed in L- and I-shaped walls when the aspect ratio was reduced from 2 to 1. Door and/or window openings were found to affect only the L-shaped walls. In addition, it was determined that failure patterns were affected from the aspect ratio and the presence of the openings.
Seismic Resistance Evaluation of Traditional Ottoman Timber-Frame Himis Houses: Frame Loadings and Material Tests
(Earthquake Engineering Research inst, 2014) Aktas, Yasemin Didem; Akyuz, Ugurhan; Turer, Ahmet; Erdil, Baris; Guchan, Neriman Sahin
Traditional Ottoman timber-frame houses ("himis") form the major part of the cultural heritage structures in Turkey. There are many studies in the literature regarding the seismic performance of himis houses, which claim that these structures have an inherent seismically resistant property. However, these studies lack a quantitative engineering approach and are based on observations made after contemporary earthquakes. This study presents the results of the seismic resistance evaluation of traditional Ottoman houses, made by means of reverse cyclic frame tests conducted on six yellow pine and two fir frames with and without infill (brick and adobe) or cladding (bagdadi and samdolma). The experimental study, which was intended to differentiate the effects of infill materials, frame geometry, and timber type, has revealed that frames with bagdadi cladding and adobe infill resulted in the best and worst structural performances, respectively, while high ductility and good energy dissipation capacity characteristics were determined.
A Simple Approach for the Calculation of Moment Capacity of Rectangular Shear Walls
(Pamukkale Univ, 2017) Erdil, Baris
Calculation of the moment capacity of reinforced concrete (RC) shear walls is a hard and time consuming task since they have more reinforcement rows. Although there exist some software to overcome this difficulty, those software require some expense. In this study, a simple equation is proposed to calculate the moment capacity (M-r) of rectangular RC shear walls which are designed according to the 2007-Turkish Earthquake Code. The proposed equation is simple because it includes variables which are easy to determine such as length and thickness of the shear wall, reinforcements in the boundary member at the tension zone and the axial load level. Moment capacities from the proposed equation are found to be very close to the ones from the detailed analysis. Using the proposed equation, charts for the moment capacity (M-r) of rectangular RC shear walls having varying dimensions and varying reinforcement ratio were developed and given in the appendix.
A Simplified Fundamental Period Equation for Rc Buildings
(Croatian Soc Civil Engineers-hsgi, 2021) Yigit, Abdullah; Erdil, Baris; Akkaya, Ismail
Considering the huge differences in the prediction and organization of equations available in the literature, this paper aims at developing a reliable equation including mass and stiffness parameters. Microtremor (ambient vibration) measurements were taken from 23 RC buildings and their fundamental periods were compared to the dynamic analysis results. Building models were then calibrated to account for the infill wall effect. After that, 156 RC buildings were 3D modelled and their dynamic analysis results were used to calibrate the proposed fundamental period equation.
Structural Performance of Masonry Buildings Under Harsh Climate and Seismic Loads
(Springer int Publ Ag, 2022) Erdil, Baris; Korkut, Fuat; Aydin, Mahsum; Yaltay, Namik
Masonry buildings in Van which is a city located at the eastern border of Turkey exposed to several earthquakes in 2020 while continuously being subjected to harsh weather conditions. Two earthquakes with Mw = 5.9 occurred on the same day and four months after another one hit the region. Besides the earthquakes 124 freeze-thaw cycles occur annually and the region has snow and rain approximately 103 days. Both continuously and periodically applied environmental exposures due to harsh weather conditions and earthquakes that is significant in a short period, affects the structural performance of the masonry buildings adversely. During the field investigations after the earthquakes, it was realized that none of the buildings comply with the available codes, foundations, and walls damaged due to the environmental exposures and those damages either increased or end up with total collapse due to the seismic loading. Besides the damaged buildings, it was observed that some buildings were strengthened locally at the corners. L shaped reinforced concrete columns were added to the cracked corners to increase the lateral capacity of the walls. That strengthening seemed to be adequate for low seismicity because no significant damage was seen.
Why Rc Buildings Failed in the 2011 Van, Turkey, Earthquakes: Construction Versus Design Practices
(Asce-amer Soc Civil Engineers, 2017) Erdil, Baris
The 2011 Van earthquakes revealed that although earthquake-resistant codes were revised after significant research and after each major earthquake, construction quality had a little progress in the region. A total of 63 RC residential buildings that collapsed or were severely damaged in 2011 Van earthquakes were investigated in detail. It was found that there is an increasing trend in terms of number of stories in Ercis, Turkey. However, not only the taller buildings experienced more damage but also the shorter ones were damaged or collapsed. Column ratio has a decreasing trend but shear wall ratio increases with time. As for the ratio of the total vertical elements to the total floor area, it has a slight decrease with time. Although some design projects provide lower reinforcements, after 1995, the reinforcement ratio was either close to 1% or greater. Reinforcement ratio at the site was found to be lower than the ones specified in the design projects. Most of the buildings had shear walls but they were mostly oriented in the weak axis of the building and the as-built shear capacity of the buildings was found to be 50-60% of their design shear capacity. Concrete compressive strength was approximately 8 MPa. Some buildings were vulnerable even under gravity loading. (C) 2016 American Society of Civil Engineers.