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Öğe Analytical Solutions Using the Equivalent Strut Tie Method of Infilled Steel Frames and Experimental Verification(Canadian Science Publishing, Nrc Research Press, 2006) Kaltakcı, M. Y.; Köken, A.; Korkmaz, H. H.Frame systems are commonly used in structural design. Beams and columns are essential in the design and analysis of these types of structures. Since no practical and generally recognized method has yet been developed to determine the failure loads of these systems, nonstructural components such as architectural walls are not usually taken into consideration in the analyses. In this study, the experimental failure loads and failure types of 30 partially or fully infilled steel frame systems were determined after testing these systems under reversed cyclic horizontal loading. After the analytical study was carried out, the failure loads and failure modes of the samples were obtained analytically using the equivalent strut tie method, and experimental and analytical results were compared.Öğe Damage and Failure Pattern of Prefabricated Structures After Major Earthquakes in Turkey and Shortfalls of the Turkish Earthquake Code(Pergamon-Elsevier Science Ltd, 2006) Arslan, M. H.; Korkmaz, H. H.; Gülay, F. G.The cost of the damage of the earthquakes in the last 10 years has been serious especially on prefabricated industrial structures. Therefore in this study, extensive, serious damage and failures in prefabricated reinforced concrete structures in the August-17, 1999 Adapazari (Turkey) and November-12, 1999 Duzce (Turkey) earthquakes have been examined. By performing a cause and effect assessment of the damage types experienced, some strengthening recommendations have been made. To investigate the causes of the damage beside the assessment of practical imperfections, a comparison between the sets of criteria encompassed in the Turkish Code, UBC-97 and Eurocode-8-98 Codes especially on the criteria of base shear force, displacement and loads acting on the nodes/connections has been made. For the sake of a more comprehensible illustration of the distinctions, the design of a pre-constructed industrial structure to the three mentioned codes has been conducted. In order to compare the above-mentioned codes a sample prefabricated structure, which totally failed after 1999 Marmara earthquake is analysed.Öğe Earthquake Hazard and Damage on Traditional Rural Structures in Turkey(COPERNICUS GESELLSCHAFT MBH, 2010) Korkmaz, H. H.; Korkmaz, S. Z.; Döndüren, M. S.During the last earthquakes in Turkey, reinforced concrete structures in the cities and masonry structures in the rural part were exposed to damage and failure. Masonry houses such as earthen, brick and stone structures are composed of building blocks with weak inter-binding action which have low tension capacity. Bending and shear forces generate tensile stresses which cannot be well tolerated. In this paper, the performance of masonry structures during recent earthquakes in Turkey is discussed with illustrative photographs taken after earthquakes. The followings are the main weakness in the materials and unreinforced masonry constructions and other reasons for the extensive damage of masonry buildings. Very low tensile and shear strength particularly with poor mortar, brittle behaviour in tension as well as compression, stress concentration at corners of windows and doors, overall unsymmetry in plan and elevation of building, unsymmetry due to imbalance in the sizes and positions of walls and openings in the walls, defects in construction such as use of substandard materials, unfilled joints between bricks, not-plump walls, improper bonding between walls at right angles etc.Öğe An experimental study on the behavior of infilled steel frames under reversed-cycling loading(SHIRAZ UNIV, 2008) Kaltakci, M. Y.; Koken, A.; Korkmaz, H. H.In this study, the behavior of nine steel frames having various infill properties under reversed-cycling loading were investigated experimentally. The steel frame systems consist of a single story with span/height ratios of 1, 1/2 and 2. The selected infill properties are no infill, brick-wall infill and brick-wall + plaster infill. The reversed-cycling loading was applied to test the specimens laterally to simulate the seismic load. Then, the displacements occurring at the specimens were measured. Strength envelopes, rigidity decreases and energy dissipation properties of the infilled frames were determined and the results obtained are compared.Öğe Experimental Study on the Behaviour of Nonductile Infilled RC Frames Strengthened With External Mesh Reinforcement and Plaster Composite(Copernicus Gesellschaft Mbh, 2010) Korkmaz, S. Z.; Kamanlı, Mehmet; Korkmaz, H. H.; Döndüren, Mahmud Sami; Çöğürcü, Mustafa TolgaThe aim of this paper is to report on an experimental study about Turkish Earthquake Code on suggested strengthening method. The proposed method uses existing brick infill walls and the strengthening is done with the application of external mesh reinforcement and plaster. 5 nonductile 1/2 scaled, one bay, two storey RC specimens were tested under a reversed cyclic loading. The first two specimens were reference specimens and the other ones were strengthened with the proposed method. The specimens contained several design and construction mistakes such as low concrete quality and improper steel detailing. Strength, stiffness and storey drifts of the test specimens were measured. The results of the test on these frames were compared with the reference specimens. The effects of the reinforced mesh plaster application for strengthening on behaviour, strength, stiffness, failure mode and ductility of the specimens were investigated. Unexpected failure modes were observed during the testing and the results were summarized in this paper.Öğe An experimental study on the seismic performance improvement of nonductile reinforced concrete structures with external shearwall application(CRC PRESS-TAYLOR & FRANCIS GROUP, 2015) Bahadir, F.; Balik, F. S.; Korkmaz, H. H.; Kamanh, M.; Unal, A.Turkey lies over one of the most active seismic zones in the world. Several destructive earthquakes resulted in high dead losses in the last century. This shows that the residental buildings with poor earthquake resistance must be rehabilitated with rapid, economical, feasible, functional and effective strengthening methods. In this study, six reinforced concrete frames with one bay-two storeys and in 1/3 scale were tested. The specimens contained several deficiencies that were commonly observed in residential buildings in Turkey. The applied lateral loading was reversed cyclic loading that simulates the earthquake exicitions. First specimen was the reference specimen and didn't contain any strengthening. The other specimens were strengthened with external RC shear walls with or without window openings. The size and position of the openings are parameters in the study. Columns of the frames also jacketed with reinforced concrete. The hysteresis curves and envelope curves were presented within the paper. In the conclusion, the capacity increase of the frame was discussed and several recommendations were presented. Test results showed that external shear walls significantly improved the lateral load carrying capacity, stiffuess and energy dissipation capacity of the bare frame.Öğe An investigation on failed or damaged reinforced concrete structures under their own-weight in Turkey(PERGAMON-ELSEVIER SCIENCE LTD, 2007) Kaltakci, M. Y.; Arslan, M. H.; Korkmaz, H. H.; Ozturk, M.In Turkey, more than 90% of building stock consists of reinforced concrete buildings. The majority of Turkey's urban population lives in multi-story apartment blocks constructed with reinforced concrete. In addition to reinforced concrete structure damages caused from especially last decade's earthquakes, there were built structures most of which are unable to carry their own-weight and are not appropriate to engineering and design criteria because of lack of interest, ignorance, lack of inspection and supervision in Turkey. Up to now, even though there are many examples, Turkey has faced two painful experiences in Diyarbakir Hicret Apartment totally collapsed in 1983 and caused significant casualties (93 dead) and in Konya Zumrut Apartment in 2004 (92 dead). The casualties in these phenomenons were more than some big earthquakes. The most significant disadvantage of reinforced concrete buildings is that after producing RC members abolishing detailing defaults cannot be possible. Except for structural damages caused from last big earthquakes, the existence of some RC buildings damaged due to their own-weight and static loading rises a necessity of control and rehabilitation of RC buildings. In the study, first of all, there is mentioned about the causes of structural damages like not obeying the standard criteria, workmanship faults, over design loads (change in the utilization purpose of the building), insufficient material quality and false revisions applied on the construction by the users. The effect of not considering the significant and fundamental criteria existing especially in TEC-98 and TBC-500-2000 on system behavior is examined. Afterwards, giving examples for reinforced concrete structures failed in a 10-year period of time only under its dead load and caused serious life and possession losses, various analyses and experimental studies related with those structures is presented. The samplings will be classified according to the locations of the damages occurred in load-bearing system members. Finally, at the end of the study, damage formation causes and necessary precautions will be specified according to the results obtained from the analytical and experimental data. (C) 2006 Elsevier Ltd. All rights reserved.Öğe Punching shear strength of flat slabs with different punching reinforcement configurations(CRC PRESS-TAYLOR & FRANCIS GROUP, 2015) Kamanh, M.; Ezer, I.; Korkmaz, H. H.In this study, an experimental investigation on the punching shear strength and behavior of flat plates is performed. The use of flat plate is popular for medium rise buildings especially for hotels, shopping centers and office buildings. The plate-column connections are the most critical parts. The brittle and sudden type of failure, called punching, is very dangerous and special attention must be paid to prevent this type of failure. In Turkish Reinforced Concrete Code the use of punching reinforcement is advised and it is stated that the capacity of the connection must be determined by experimental studies. The results of a test series on the punching behavior of slabs with different punching reinforcements are presented. Totally four specimens representing an interior column-slab connection was modeled and tested. Specimens were provided different shear reinforcement arrangements except for the specimen SRO which is a reference specimen and tested to see the reference behavior and capacity. The other four specimens include different punching reinforcement configurations. The plate concrete was in the normal strength concrete range. The load was applied to the column stub concentrically and flexural reinforcement ratios were kept constant for all specimens. The loaddisplacement curves as well as the load-rotation curves were presented in this study. Also Turkish Reinforced Concrete Code capacity predictions were compared with the test results.Öğe Seismic performance improvement of infilled nonductile RC frames(CRC PRESS-TAYLOR & FRANCIS GROUP, 2015) Korkmaz, S. Z.; Kilic, A.; Korkmaz, H. H.; Kamanh, M.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. This type of strengthening technique is recently added to the new Turkish Earthquake Code (2007). 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 Y, 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 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 results of test on these frames were compared with reference specimens. 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 Shaking table tests on strengthening of masonry structures against earthquake hazard(COPERNICUS GESELLSCHAFT MBH, 2010) Ersubasi, F.; Korkmaz, H. H.Turkey and neighborhood countries like Greece and Iran are situated on an active earthquake region. Masonry type structures are very common on these countries, especially on the rural areas. During the last earthquakes, several masonry type houses were collapsed, causing loss of life and property. Strengthening methods of masonry houses were discussed in this study. The paper summarizes the results of a experimental programme carried out on models, scaled 1/10, of one-storey masonry buildings. First specimen tested was the reference specimen and used for comparison purposes. Other specimens contained several strengthening strategies. A total of 9 specimens were tested. The results allow to assess the efficiency of the various strengthening techniques employed.Öğe Use of steel plate shear walls for the lateral rigidity improvement of reinforced concrete frame(CRC PRESS-TAYLOR & FRANCIS GROUP, 2015) Korkmaz, S. Z.; Korkmaz, H. H.Turkey is situated on a very active earthquake zone of the world. The seismic rehabilitation of existing buildings are required for future earthquakes. The main problem in Turkish building stock is the insufficient lateral rigidity. Recently, the steel shear walls are used to increase the stiffuess of the frames for steel structures. It has several advantages compared to the steel bracings. The Steel plate Shear Walls (SPSW) are composed a diagonal tension field across the opposite comers of the frame. In this study, use of SPSW's were investigated experimentally. The generic specimen was 1/3 scaled, two storey, one bay RC frame. It represents the exterior frame of the building. The first specimen was the reference specimen which didn't contain any strengthening. In the other specimens steel plate shear walls were used to cover the external facade of the frame opening. These SPSW's are intented to increase the lateral stiffuess of the frame. Lateral reversed cyclic hystersis curves of the specimens, envelope curves, maximum lateral load carrying capacities, energy absorption capacities, increase in lateral rigidities were evaluated.Öğe What is to be learned from damage and failure of reinforced concrete structures during recent earthquakes in Turkey?(PERGAMON-ELSEVIER SCIENCE LTD, 2007) Arslan, M. H.; Korkmaz, H. H.In Turkey, generally, building stock is formed from reinforced concrete structures and during last earthquakes, a large number of these buildings in the epicenter regions were collapsed leading to widespread destruction and loss of life. In this paper, the performance of reinforced concrete buildings during recent earthquakes in Turkey is discussed. The objective of this paper is to provide a brief overview of damage as observed following the earthquakes. The failure modes consist of foundation failures, soft stories, strong beams and weak columns, lack of column confinement, poor detailing practice and non-structural damages. Observations from the earthquake damages are discussed and compared with TEC-98 (Turkish Earthquake Code) and TBC-500-2000 (Turkish Building Code) requirements. Measurements of some damaged reinforced concrete member examples are given and important general lessons learned from these earthquakes are formulated. Finally, a short overview of the emergency management measures taken is also presented. (C) 2006 Elsevier Ltd. All rights reserved.
