Quasi-static and pseudo-dynamic testing of infilled RC frames retrofitted with CFRP material

Özkaynak, Hasan; Yüksel, Ercan; Büyüköztürk, Oral; Yalçın, Cem; Dindar, Ahmet Anıl

doi:10.1016/j.compositesb.2010.11.008

Cited by 29 publications

(6 citation statements)

References 12 publications

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“…Polimer malzemeler içinde karbon liflli polimerler (CFRP) en popüler olanıdır. Bu malzemeden üretilen kumaşlar, farklı tertipler denenmiş olsa da [10,11], dolgu duvara genellikle köşegeni boyunca [12][13][14] epoksi ile yapıştırılıp çevresindeki betonarme çerçeveye çeşitli yöntemlerle [15,16] bağlantısı sağlanmaya çalışılır. CFRP ile güçlendirme, geleneksel güçlendirme yöntemleriyle de karşılaştırılmıştır [17,18].…”

Section: şEkil 2 üSt Köşedeki Tuğlanın Ezilmesiyle Gözlenen Davranışunclassified

Delikli levhalarla güçlendirilmiş tuğla duvarların hesabı için öneriler

Özbek

Aykaç

Can

et al. 2018

Gazi Üniversitesi Mühendislik-Mimarlık Fakültesi Dergisi

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Practical calculation methods have been developed for brick walls strengthened with perforated plates  Methods include strength, stiffness and deformation limits  The developed methods are consistent with the experimental results Figure A. Behavior of test specimens even after excessive drifts (a) modelling approach of strengthened infill wall (b) Purpose: Strengthening the infill walls of the RC frame with perforated steel plates led to ductile behavior and no significant loss in strength up to 7.5% drift ratio (Fig. A. (a)). In addition to the ductile behavior, half scaled experiments indicated that increases in the strength reaching two times the reference value could be obtained. The aim of the present study is to develop calculation and modelling approaches for designers who are willing to choose this strengthening method. Theory and Methods: The general consensus is that an equivalent-strut approach can be successfully used for analytical studies of infilled RC frame systems. Experimental behavior pointed out that this strut could be modeled as shown in the Fig. A. (b). The equation that calculates the strength of strengthened infill wall (Vstr) in this model was obtained by developing equation in FEMA-306 (1998). The stiffness of the strengthened infill wall was also derived according to the compression strut analogy. Results: Equations, developed for calculating the strength and stiffness values of the infill walls strengthened with perforated steel plates, provided analytical estimates in rather close agreement with the experimental results. The highest deviation of the calculated strength values from the experimental ones was 12% on the conservative side (smaller than the experimental result). The average of the deviations were 3% and 7% for the strength and stiffness estimations, respectively. Conclusion: The analytical approach developed for strengthened infill brick walls with perforated plates was consistent with the experimental values. Hence, it is concluded that derived practical equations and claimed behavior can be used for the assignment of strength, stiffness and deformation limits to the equivalent compression strut model inside the RC frames.

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Section: şEkil 2 üSt Köşedeki Tuğlanın Ezilmesiyle Gözlenen Davranışunclassified

Delikli levhalarla güçlendirilmiş tuğla duvarların hesabı için öneriler

Özbek

Aykaç

Can

et al. 2018

Gazi Üniversitesi Mühendislik-Mimarlık Fakültesi Dergisi

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“…They are representing the lower and upper story masses, which are scaled down from the prototype structure. The experimental details can be found in Ozkaynak's PhD dissertation [17] and Ozkaynak et al [18].…”

Section: Masonry Infill Walls In Rc Frames As a Source Of Structural mentioning

confidence: 99%

Masonry infill walls in reinforced concrete frames as a source of structural damping

Özkaynak

Yüksel

Yalçın

et al. 2013

Earthq Engng Struct Dyn

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SUMMARY This paper presents the results of an experimental study on the determination of damping characteristics of bare, masonry infilled, and carbon fiber reinforced polymer retrofitted infilled reinforced concrete (RC) frames. It is well known that the masonry infills are used as partitioning walls having significant effect on the damping characteristics of structures as well as contribution to the lateral stiffness and strength. The main portion of the input energy imparted to the structure during earthquakes is dissipated through hysteretic and damping energies. The equivalent damping definition is used to reflect various damping mechanisms globally. In this study, the equivalent damping ratio of carbon fiber reinforced polymer retrofitted infilled RC systems is quantified through a series of 1/3‐scaled, one‐bay, one‐story frames. Quasi‐static tests are carried out on eight specimens with two different loading patterns: one‐cycled and three‐cycled displacement histories and the pseudo‐dynamic tests performed on eight specimens for selected acceleration record scaled at three different PGA levels with two inertia mass conditions. The results of the experimental studies are evaluated in two phases: (i) equivalent damping is determined for experimentally obtained cycles from quasi‐static and pseudo‐dynamic tests; and (ii) an iterative procedure is developed on the basis of the energy balance formulation to determine the equivalent damping ratio. On the basis of the results of these evaluations, equivalent damping of levels of 5%, 12%, and 14% can be used for bare, infilled, and retrofitted infilled RC frames, respectively. Copyright © 2013 John Wiley & Sons, Ltd.

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“…Researches on seismic evaluation of FRP-retrofitted masonry-infilled RC frames received greater attention after the last decade. However, the research efforts were largely limited to the basic one-story one-bay structures retrofitted with FRP (Altın et al, 2008(Altın et al, , 2012Kakaletsis, 2011;Ozkaynak et al, 2011;Yuksel et al, 2010). These experimental studies indicated that the reasonable FRP retrofitting schemes could significantly enhance the overall structural seismic performance by preventing the brittle failure and out-ofplane instability of infill walls, changing the load transfer path between infills and RC frame, reducing the damage to the joint core regions, and improving the seismic resistance of beams and columns.…”

Section: Introductionmentioning

confidence: 99%

Numerical modeling and seismic evaluation of masonry-infilled reinforced concrete frames retrofitted with carbon fiber–reinforced polymer wraps

Pan

Yan

Wang

et al. 2018

Advances in Structural Engineering

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This article investigates the efficiency of various retrofitting schemes using carbon fiber-reinforced polymers in improving the seismic performance of a substandard masonry-infilled reinforced concrete frame. One virtual five-story reinforced concrete frame was designed according to out-of-date Chinese codes. In total, 15 carbon fiber-reinforced polymers retrofitting schemes were adopted before earthquakes, and three sets of earthquakes representing low, medium, and high frequency contents were selected to conduct the incremental dynamic analysis. The influence of infills' collapse due to out-of-plane effect was discussed detailedly, and then, the effectiveness of different retrofitting schemes was evaluated. It was found that the collapse of infills obviously reduced the seismic capacity and finally resulted in a soft-story failure mechanism for the reinforced concrete frame. For earthquakes with low frequency content, the enhancement efficiency of retrofitting infills or both columns and infills was increased with the increase in the number of retrofitted stories; however, for medium and high earthquake frequency contents, retrofitting infills or both columns and infills were inefficient when less than half of the structure height was retrofitted. Among the adopted 15 schemes, carbon fiber-reinforced polymers retrofit of both columns and infills along the full building height was found to be the most efficient. Improper selection of a retrofitting scheme could lead to the change of soft-story location. The inter-story drift ratio capacity of effectively retrofitted frames can meet the requirements of current seismic code.

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Quasi-static and pseudo-dynamic testing of infilled RC frames retrofitted with CFRP material

Cited by 29 publications

References 12 publications

Delikli levhalarla güçlendirilmiş tuğla duvarların hesabı için öneriler

Delikli levhalarla güçlendirilmiş tuğla duvarların hesabı için öneriler

Masonry infill walls in reinforced concrete frames as a source of structural damping

Numerical modeling and seismic evaluation of masonry-infilled reinforced concrete frames retrofitted with carbon fiber–reinforced polymer wraps

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