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Öğe Behaviour of Strengthened RC Frames with Eccentric Steel Braced Frames(E D P SCIENCES, 2017) Kamanli, Mehmet; Unal, AlptugAfter devastating earthquakes in recent years, strengthening of reinforced concrete buildings became an important research topic. Reinforced concrete buildings can be strengthened by steel braced frames. These steel braced frames may be made of concentrically or eccentrically indicated in Turkish Earthquake Code 2007. In this study pushover analysis of the 1/3 scaled 1 reinforced concrete frame and 1/3 scaled 4 strengthened reinforced concrete frames with internal eccentric steel braced frames were conducted by SAP2000 program. According to the results of the analyses conducted, load-displacement curves of the specimens were compared and evaluated. Adding eccentric steel braces to the bare frame decreased the story drift, and significantly increased strength, stiffness and energy dissipation capacity. In this strengthening method lateral load carrying capacity, stiffness and dissipated energy of the structure can be increased.Öğe Effect of eccentricity on the internal forces on the columns of a reinforced concrete building(Selçuk Üniversitesi, 2022) Cengiz, Salih; Solak, Abdulkadir; Unal, Alptug; Kamanli, MehmetIn this study, a five-storey reinforced concrete building was modeled with the IdeCAD V10 program, and the internal force changes in the columns were examined by creating different eccentricity states. While creating the eccentricity, the center of rigidity was moved away from the center of mass by changing the size of one of the corner columns. The columns whose internal strength is examined are the corner, edge and interior columns on the ground, third and fifth floors of the building. As a result of the analysis, the bending moment and shear force values in the ground floor columns have the highest values, while the torsional moment values are higher at the third floor.Öğe Evaluation of a Gravity Load Designed Reinforced Concrete Structure Failed Under Its Own Weight Due to Creep in Concrete(TRANS TECH PUBLICATIONS LTD, 2013) Kaltakci, Mevlut Yasar; Korkmaz, Hasan Husnu; Kamanli, Mehmet; Ozturk, Murat; Arslan, Musa HakanTurkish building stock is commonly composed of reinforced concrete moment resisting frames. Recent earthquakes in Turkey resulted thousands of failed or heavily damaged residential houses and office buildings. In addition of the earthquake failures, reinforced concrete structures may also failed only under their own weight. There are several examples such as Hicret Apartment in Diyarbakir (1983), Zumrut Apartment in Konya, in central Anatolia, Huzur Apartment in Istanbul (2007). On February 2nd, 2004 a 9-story reinforced concrete building in Konya (Zumrut Apartment) collapsed leaving 92 people dead. The first author of the paper was governmentally charged about the investigation of the failure causes. Carrot samples were taken from the concrete columns and steel samples were obtained from the disaster area. The dimensions of the structural members were determined. The structure was modeled in three dimensional space and vertical collapse analyses were conducted. The one of the main cause of failure was determined as the creep of the concrete occurred in excessively loaded columns. The main reasons of the damages and failures were determined to be the insufficiency in material quality, mistakes made in load selection and the inappropriate load-carrying dimensions. The construction mistakes and not obeying the design drawings are the other flaws. In this paper detailed information about the structure, creep analyses and vertical collapse analyze results were depicted in understandable format.Öğe Experimental and Analytical Study of Masonry Constructions Reinforced with Bed Joints(CARL HANSER VERLAG, 2014) Kamanli, Mehmet; Cogurcu, Mustafa TolgaIn this study, investigation was conducted on the out-of-plane fracture under repeated reversing loads of specimens of unreinforced masonry wall models, a suitable building material found worldwide, strengthened by bed joints using FRP (fiberglass reinforced plastic) with epoxy resin, by production of two separate wall samples composed of materials with identical characteristics in a 1 : 1 ratio. It was also observed that the fracture type became brittle and the pour lines indicated that it did not have tensile strength. Approximately, a 3.5 increase in withstanding breakage under seismic forces was observed in the performance of the wall strengthened by FRP with epoxy reinforcements in the bed joints. Furthermore, the shear strength of the model masonry wall was 48 % less than that attained in the wall strengthened by bed joints and it was determined that the energy absorption of the model masonry wall was 22 % less than that of the wall strengthened by bed joints. Additionally, while the masonry wall in the test which was not strengthened broke under repeated reversing loads at 65 kN, the break load of the strengthened masonry wall was ascertained to be 80 kN. The accuracy and application of the results of the studies conducted were also scrutinized by running finite element stress analysis and numerical solutions using an ANSYS computer-supported analysis program.Öğe Experimental study of strengthening of RC frames with column retrofitting(Selçuk Üniversitesi, 2014) Unal, Alptug; Balik, Fatih Suleyman; Bahadir, Fatih; Korkmaz, Hasan Husnu; Kaltakci, Mevlut Yasar; Kamanli, MehmetRecently, researches related with strengthening have been increased. In most of these studies, strengthening of reinforced concrete frames with inadequate earthquake resistance was searched. However, it is known that there are buildings with inadequate earthquake resistance as well as buildings with both inadequate earthquake resistance and inadequate axial load bearing capacity. A 1/3 geometric scaled reinforced concrete frame with inadequate earthquake resistance and inadequate axial load strength modeled as a sample building was strengthened with column retrofitting and tested under vertical and lateral loads. In this study, two 1/3 geometric scaled specimens were tested under the effect of reversible repeatable lateral loads simulating earthquake. One of these samples is a bare reinforced concrete frame representing buildings with inadequate earthquake resistance and axial load strength as well as including building defects without any strengthening which are frequently encountered in our country. The second experiment element was constructed in order to represent the buildings which necessitate strengthening due to earthquake loads and axial loads. In this specimen, the columns were strengthened by retrofitting from three sides. The hysteresis curves, envelope curves, rigidity, ductility and consumed energy graphs of these tested elements are given and the differences between them were investigated and interpreted. In the final section, the experimental results obtained were evaluated, interpreted and suggestions were made.Öğe An Experimental Study on Reinforced Concrete Infilled Frames with Openings(TRANS TECH PUBLICATIONS LTD, 2013) Balik, Fatih Suleyman; Korkmaz, Hasan Husnu; Kamanli, Mehmet; Bahadir, Fatih; Korkmaz, Serra Zerrin; Unal, AlptugIn the last decade, seven major earthquakes caused significant casualties and extensive structural failures. Thousands of RC buildings were severely damaged or collapsed in Turkey due to various deficiencies. This has initiated experimental studies on strengthening methods and intensive researches regarding the rehabilitation of reinforced concrete structures by introducing reinforced concrete infill walls were carried out. Strengthening of reinforced concrete frames by cast-in-place reinforced concrete infills is commonly used in practice. Many structures were also repaired using this technique after the recent earthquakes. In this experimental research, six, one-bay/two-story, 1/3-scaled non-ductile, undamaged reinforced concrete (RC) frames were constructed and tested to investigate the behavior of frames strengthened by introducing infills with or without openings. The test specimens were subjected to reversed cyclic quasi-static lateral loading. The specimens were constructed with the most commonly observed deficiencies in residential RC buildings in Turkey. The first specimen was the reference bare specimen and contained no strengthening. The other specimens were infilled with RC panels with openings having different ratios and configurations. Strength, stiffness and storey drifts of the test specimens were measured and compared. Test results indicated that infilled RC frames displayed significantly higher lateral strength and stiffness than the non-ductile bare frame considerably.Öğe Predicting the flexural behaviour of reinforced concrete and lightweight concrete beams by ANN(NATL INST SCIENCE COMMUNICATION-NISCAIR, 2012) Kamanli, Mehmet; Kaltakci, M. Yasar; Bahadir, Fatih; Balik, Fatih S.; Korkmaz, H. Husnu; Donduren, M. Sami; Cogurcu, M. TolgaIn this study, artificial neural network (ANN) method is used to predict the deflection values of beams and compared with the experimental results of a testing series. For this purpose six reinforced concrete beams with constant rectangular cross-section are prepared and tested under pure bending. The concrete of the test specimens is casted using the lightweight aggregates obtained from volcanic sediments. The lightweight concrete has some advantages comparing the traditional concrete, such as less self weight, less earthquake forces due to decreased mass, good sound and thermal insulation. The use of lightweight concrete in the construction industry is popular due to various advantages. The neural network procedure is applied to determine or predict the deflection values of 1/1 scaled model beams. The analytical results are compared with the test results and further predictions, including different mix designs can be possible at the end of the study. As a result, while the statistical values RMSE, R-2 and MAE from training in ANN model are found as 0.266, 99.2% and 0.216, respectively, these values are found in testing as 0.370, 96.47% and 0.419, respectively.Öğe Seismic improvement of infilled nonductile RC frames with external mesh reinforcement and plaster composite(TECHNO-PRESS, 2015) Kamanli, Mehmet; Korkmaz, Hasan H.; Unal, Alptug; Balik, Fatih S.; Bahadir, Fatih; Cogurcu, Mustafa T.The objective of this paper is to report the result of an experimental program conducted on the strengthening of nonductile RC frames by using external mesh reinforcement and plaster application. The main objective was to test an alternative strengthening technique for reinforced concrete buildings, which could be applied with minimum disturbance to the occupants. Generic specimen is two floors and one bay RC frame in 1/2 scales. The basic aim of tested strengthening techniques is to upgrade strength, ductility and stiffness of the member and/or the structural system. Six specimens, two of which were reference specimens and the remaining four of which had deficient steel detailing and poor concrete quality were strengthened and tested in an experimental program under cyclic loading. The parameters of the experimental study are mesh reinforcement ratio and plaster thickness of the infilled wall. The effects of the mesh reinforced plaster application for strengthening on behavior, strength, stiffness, failure mode and ductility of the specimens were investigated. Premature and unexpected failure mode has been observed at first and second specimens failed due to inadequate plaster thickness. Also third strengthened specimen failed due to inadequate lap splice of the external mesh reinforcement. The last modified specimen behaved satisfactorily with higher ultimate load carrying capacity. Externally reinforced infill wall composites improve seismic behavior by increasing lateral strength, lateral stiffness, and energy dissipation capacity of reinforced concrete buildings, and limit both structural and nonstructural damages caused by earthquakes.Öğe Strengthening of Gravity Load Designed Reinforced Concrete Frames With the External RC Shear Walls(TRANS TECH PUBLICATIONS LTD, 2013) Bahadir, Fatih; Kamanli, Mehmet; Korkmaz, Hasan Husnu; Balik, Fatih Suleyman; Unal, Alptug; Korkmaz, Serra ZerrinTurkey is situated on a very earthquake zone of the world namely Alp-Himalayan Earthquake Zone. Several destructive earthquakes resulted in high dead losses in the last century. Turkish building stock consisted of nonductile RC framed structures commonly 3 to 7 stories. The common properties of the existing structures is the poor lateral resistance. The residental buildings with poor earthquake resistance must be rehabilitated with a rapid, economical, feasible and effective strengthening methods. The external shear wall addition to the existing poor frame is studied experimentally in this study. 6 specimens were tested under reversed cyclic lateral loading simulating the seismic action. The first specimen was the reference specimen and didn't contain any strengthening and tested to see reference behaviour. The other specimens were strengthened with external shear walls with or without openings. The size of the openings is a parameter in the study. Secons specimen didn't contain any opening. Columns of the frames also jacketed with reinforced concrete. The maximum lateral load carrying capacity, ductility capacities, energy consuption capacities, improvement in the lateral rigidities were investigated.Öğe Strengthening of Reinforced Concrete Frames Not Designed According to TDY2007 With External Shear Walls(TRANS TECH PUBLICATIONS LTD, 2013) Unal, Alptug; Kaltakci, Mevlut Yasar; Balik, Fatih Suleyman; Korkmaz, Hasan Husnu; Bahadir, Fatih; Korkmaz, Serra Zerrin; Kamanli, MehmetRecently repair and strengthening of existing buildings become a popular research topic. The strengthening of buildings necessitates the evacuation of the structure. On the other hand, school, hospital type structures must continue their function. In this study exterior shear wall addition to the existing exterior frames is proposed. Since the application is applied to the exterior of the building, the structure can continue its function during the application. In this study, 1/3 scaled 4 specimens were tested under reversed cyclic loading simulating the seismic action. First reference specimen was the bare frame and didn't contain a strengthening and tested to see the reference behavior. Specimens have several design mistakes to represent the existing older structures. The other specimens retrofitted with different configurations. The second specimen was strengthened with exterior shear walls and contained a window opening. The last specimen was also retrofitted with exterior shear wall but the shear walls were divided into two pieces. The load-displacement curves, envelope curves, relative displacement curves, energy absorption curves and rigidity curves were presented and compared within the paper. In the conclusion, the capacity increase of the frame was discussed and several recommendations were presented.Öğe Sudden Complete Collapse of Zumrut Apartment Building and the Causes(ASCE-AMER SOC CIVIL ENGINEERS, 2013) Kaltakci, M. Yasar; Kamanli, Mehmet; Ozturk, Murat; Arslan, M. Hakan; Korkmaz, H. HusnuIn recent years, buildings and structures in Turkey have frequently failed or suddenly sustained damage because of their own weight or other loads. The most dramatic failure was the Zumrut Apartment Building disaster: a 9-story RC building in Konya that collapsed on February 2, 2004, leaving 92 people dead. This study will investigate the cause of the building damage and failure. The significant mistakes made during the design and construction of the building will also be considered. This study was divided into three sections: site investigation, analytical study, and experimental study. The evaluation of the building failure relating to the vertical load-bearing members will be presented using observations from the site investigations, the test results obtained from specimens taken from the failed building, and the findings of an analytical study involving modeling the building using the finite-element method.
