Seismic upgrading of reinforced concrete frames with structural steel elements

Özçelik, Ramazan
This thesis examines the seismic internal retrofitting of existing deficient reinforced concrete (RC) structures by using structural steel members. Both experimental and numerical studies were performed. The strengthening methods utilized with the scope of this work are chevron braces, internal steel frames (ISFs), X-braces and column with shear plate. For this purpose, thirteen strengthened and two as built reference one bay one story portal frame specimens having 1/3 scales were tested under constant gravity load and increasing cyclic lateral displacement excursions. In addition, two ½ scaled three bay-two story frame specimens strengthened with chevron brace and ISF were tested by employing continuous pseudo dynamic testing methods. The test results indicated that the cyclic performance of the Xbrace and column with shear plate assemblage technique were unsatisfactory. On the other hand, both chevron brace and ISF had acceptable cyclic performance and these two techniques were found to be candidate solutions for seismic retrofitting of deficient RC structures. The numerical simulations by conducting nonlinear static and dynamic analysis were used to estimate performance limits of the RC frame and steel members. Suggested strengthening approaches, chevron brace and ISF, were also employed to an existing five story case study RC building to demonstrate the performance efficiency. Finally, design approaches by using existing strengthening guidelines in Turkish Earthquake Code and ASCE/SEI 41 (2007) documents were suggested.


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Soydaş, Ozan; Yakut, Ahmet; Department of Civil Engineering (2009)
An analytical study was carried out to evaluate shear wall indexes for low to mid-rise reinforced concrete structures. The aim of this study was to evaluate the effect of different shear wall ratios on performance of buildings to be utilized in the preliminary assessment and design stages of reinforced concrete buildings with shear walls. In order to achieve this aim, forty five 3D building models with two, five and eight storeys having different wall ratios were generated. Linearly elastic and nonlinear st...
Seismic Retrofit of Deficient RC Structures with Internal Steel Frames
ÖZÇELİK, RAMAZAN; Akpinar, Ugur; Binici, Barış (2011-12-01)
This paper describes an experimental study on internal steel frames (ISFs) to retrofit seismically deficient reinforced concrete (RC) frames. One reference and six strengthened frame specimens were tested under constant gravity load and cyclic lateral displacement excursions. Installation of the ISF with and without anchors to the RC frame was examined. Test results showed that the snug tight ISF installed inside an RC frame may suffice to realize the benefit of implementing ISFs. If the horizontal shear st...
Nonlinear analysis of reinforced concrete frame structures
Çiftçi, Güçlü Koray; Polat, Mustafa Uğur; Department of Civil Engineering (2013)
Reinforced concrete frames display nonlinear behavior both due to its composite nature and the material properties of concrete itself. The yielding of the reinforcement, the non-uniform distribution of aggregates and the development of cracks under loading are the main reasons of nonlinearity. The stiffness of a frame element depends on the combination of the modulus of elasticity and the geometric properties of its section - area and the moment of inertia. In practice, the elastic modulus is assumed to be ...
Explicit nonlinear analysis for quasi-static behavior of frame structures with pid control and mass scaling
Kocamaz, Korhan; Tuncay, Kağan; Department of Civil Engineering (2018)
Performance-based seismic design of reinforced concrete frame systems requires time history analysis of the structural model under earthquake loads and estimation of damage in the members. Time history analysis of these structures is usually performed using implicit time integration methods. For the implicit integration methods, divergence of the solution is typically treated as the onset of collapse of modelled system. In this study, a nonlinear analysis platform that enables the analysis of the effect of ...
Seismic strengthening of rectangular reinforced concrete columns using fiber reinforced polymers
ÖZCAN, OKAN; Binici, Barış; Ozcebe, Guney (2010-04-01)
In recent years, fiber-reinforced polymers have been widely utilized to improve the seismic performance of deficient RC columns. In this study, the flexural behavior of CFRP strengthened rectangular RC columns with plain bars and insufficient confining steel was investigated Five specimens, representing a typical deficient building column with poor transverse reinforcement detailing and low concrete strength, were tested under cyclic displacement excursions and constant axial load. The beneficial effect of ...
Citation Formats
R. Özçelik, “Seismic upgrading of reinforced concrete frames with structural steel elements,” Ph.D. - Doctoral Program, Middle East Technical University, 2011.