In this paper, wet-mixed shotcrete panels are proposed instead of reinforced concrete (RC) shear walls for the retrofitting of vulnerable RC frames. The general behavior of the retrofitted frames responding in-plane lateral loading is investigated in detail. The experimental work is composed of retrofitting of undamaged and damaged RC frames. Nearly 1/2 scale, one bay and one story specimens were tested under external loads simulating earthquake effects. To assess the effectiveness of the technique, the results of the retrofitted frames were also compared with a bare frame's and a conventional shear wall retrofitted frame's. The experimental study shows that the wet-mixed shotcrete panels added to vulnerable RC buildings increases the lateral load carrying capacity, the lateral rigidity and the energy dissipation capacity of the system. It is considered that the technique can be used as an efficient, practical and cost effective method in retrofitting of existing vulnerable RC buildings.

Large number of vulnerable reinforced concrete (RC) buildings exists in earthquake prone areas. These low cost residential and/or commercial buildings, which are three to seven-stories high, usually do not receive essential engineering services during the construction phase. Finding cheap, easily applicable and occupant friendly retrofitting techniques are extremely important to reduce the seismic risk of these buildings. As an attempt to this, a particular type of high strength clay brick is studied to evaluate its potential for the structural retrofitting. A set of experiment was conducted to assess the important mechanical characteristics of the infill walls made from these bricks. Also the performance of two RC frames retrofitted with these walls, having different connection details between the wall and RC members was examined experimentally. The analytical nonlinear static analyses of these specimens have been performed using SeismoStruct to achieve some model parameters for representing the "infill wall model" in the program. Adaptive pushover and nonlinear time history analyses were conducted to investigate the performance of a six storey representative RC frame retrofitted with these walls. Evaluation of the results obtained in these analyses prove that this retrofitting technique introduces important strength and stiffness increments to the structure, regarding its seismic demands, which are similar to the results obtained from the experiments.

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The work presented in this study aimed to investigate the behaviour of vulnerable reinforced concrete frames after retrofitted with wet-mixed shotcrete panels. Application of this retrofitting technique on a representative bare frame is examined by pushover and nonlinear dynamic time history analysis (NDTHA). Depending on the capacity curves attained in the pushover analyses, maximum base shear capacity of the frame is increased from 16% to 39% of the seismic weights after retrofitted with shotcrete panels. On the other hand, the displacement capacity of the retrofitted frame decreased by 2.8 times compared to the bare frame. The NDTHA performed for the selected earthquake records produces the results in terms of strains of confined concrete and longitudinal reinforcement that several cross sections of the bare frame have attained the collapse state defined in Turkish Earthquake Code (TEC 2007) however the retrofitted frame performs within the minimum damage state.Keywords: Wet-mixed shotcrete, strengthening, reinforced concrete frame, pushover analysis, nonlinear dynamic time history analysis GÜÇLENDİRME AMACI İLE ISLAK KARIŞIMLI PÜSKÜRTME BETON PANELLERİN UYGULANMASI ÖZ Bu çalışma, ıslak karışımlı püskürtme beton paneller ile güçlendirilmiş zayıf betonarme çerçevelerin davranışlarını araştırmayı hedeflemektedir. Bu güçlendirme yönteminin temsili yalın bir çerçeve üzerine uygulaması, itme ve zaman tanım alanında doğrusal olmayan dinamik analizleri ile incelenmiştir. İtme analizi sonucunda elde edilen kapasite eğrileri; püskürtme beton paneller ile güçlendirilmiş çerçevenin maksimum taban kesme kuvveti kapasitesinin, sismik ağırlığının %16'dan %39'a çıktığı gözlemlenmiştir. Diğer taraftan güçlendirilmiş çerçevenin deplasman kapasitesi, yalın çerçeveye göre 2.8 kat azalmıştır. Seçilen deprem kayıtları ile yapılmış olan zaman tanım alanında doğrusal olmayan analiz ile üretilen sonuçlar; yalın çerçeveye ait çeşitli enkesitler sarılmış beton ve ana donatı davranışları bakımından incelendiğinde, Deprem Yönetmeliğinde tanımlanmış olan göçme bölgesinde olduğunu göstermiştir. Ancak çerçeve güçlendirildikten sonra kesitlerin, minimum hasar bölgesinde kaldıkları gözlemlenmiştir.Anahtar Kelimeler: Islak karışımlı püskürtme beton, güçlendirme, betonarme çerçeve, itme analizi, zaman tanım alanında doğrusal olmayan dinamik analizi * Corresponding author / Sorumlu yazar.

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