Seismic retrofit of non-ductile reinforced concrete frames with chevron braces

Binici, Barış
Akpinar, Ugur
The use of chevron braces for seismic strengthening of existing non-ductile reinforced concrete frames was investigated experimentally and numerically. Five strengthened and two as-built reference portal frame specimens were tested under a constant gravity load and increasing cyclic lateral displacement excursions. The test results indicated that steel brace retrofitting increased the lateral stiffness, strength and energy dissipation capacity significantly. Specimens strengthened with square hollow sections experienced significant strength degradation upon brace buckling, but a lateral strength of about 3.5 times the strength of bare frames was maintained up to a drift ratio of about 2% in all strengthened specimens. Non-linear cyclic analysis was conducted to simulate the behaviour of the test specimens. A satisfactory agreement with estimated and observed load-deformation responses was observed. Using test observations and simulation results, the deformation capacity limits of chevron brace strengthened deficient frames were discussed. A parametric study was conducted to investigate the effectiveness of the chevron brace retrofitting for different brace sizes and column axial loads. Finally, a non-linear time history analysis was performed for a building frame of a deficient existing four-storey three-bay reinforced concrete structure by using two chevron brace sections in this study.


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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...
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Özçelik, Ramazan; Binici, Barış; Department of Civil Engineering (2011)
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 grav...
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In this study, the in-plane seismic behavior of autoclaved aerated concrete (AAC) vertical load-bearing wall panels is examined. Because of the complex behavior of AAC shear walls under cyclic lateral loading and axial load, the design provisions are fundamentally important. The main objective of this study is to validate proposed design provisions for AAC structures in Turkey. Six specimens with different properties and geometries were constructed and tested at Structural Mechanics Laboratory of METU. Mech...
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The impact of seismic retrofitting of typical Illinois bridges, via response modification using friction pendulum bearings (FPB), on the state economy is studied. For this purpose, two typical bridges with distinct characteristics were selected by Illinois Department of Transportation (IDOT). The seismic analyses of the bridges revealed that the bearings, wingwalls and substructures are vulnerable and need to be retrofitted. Conventional retrofitting strategies are developed for the bridges and the retrofit...
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Energy dissipation characteristics of structural members which exhibit both strength and stiffness deterioration under imposed displacement reversals are investigated. In the experimental part, 17 reinforced concrete beam specimens were tested under constant and variable amplitude inelastic displacement cycles. The constant-amplitude tests were employed to determine the low-cycle fatigue behaviour of specimens where the imposed displacement amplitude was the major variable. A two-parameter fatigue model was...
Citation Formats
R. ÖZÇELİK, B. Binici, and U. Akpinar, “Seismic retrofit of non-ductile reinforced concrete frames with chevron braces,” PROCEEDINGS OF THE INSTITUTION OF CIVIL ENGINEERS-STRUCTURES AND BUILDINGS, pp. 326–341, 2013, Accessed: 00, 2020. [Online]. Available: