SEISMIC RETROFIT OF MASONRY AND RC ELEMENTS WITH FRP COMPOSITES – RESEARCH AND APPLICATION T. Nagy-György 1 , V. Stoian 1 , D. Dan 1 , C. Dăescu 1 , D. Diaconu 1 , M. Moşoarcă 2 SUMMARY The paper presents a description of the theoretical studies and the results of the experimental tests carried out on brick masonry walls and different reinforced concrete elements, retrofitted using fibre reinforced polymer composites. All the experimental work has been carried out in the Civil Engineering Laboratory of the Politehnica University of Timişoara, Romania. In the first part of the article there are described several investigations done on clay brick masonry walls subjected to in-plan shear loads, retrofitted with FRP composites on one side; the second part is dedicated to RC plane shear walls with monotonic and staggered openings and beams with dapped ends strengthened with composites, too. INTRODUCTION In the past few years, in many research centres around the world there was investigated a new consolidation technique, which involves fibre reinforced polymer (FRP) composites overlays, in this way increasing the in- plan and out-of-plan strength and stiffness of the structural elements. The FRPs used in constructions is a non-ductile material, with high strength-to-weight ratio, low thickness and high durability. Although the initial material cost of this solution is higher than the investigated traditional retrofitting methods, such as reinforced concrete overlays, these materials have been used in numerous applications worldwide to retrofit structural masonry walls and different reinforced concrete (RC) elements, such as beams, columns or walls. Their efficiency and ease of application lead to a substantial economy, in several situations. In the Department of Civil Engineering of the Politehnica University of Timisoara, this solution of retrofitting is under study in a frame of several research projects. The elements under investigations are: unreinforced clay brick masonry walls subjected to in-plan shear loads; the RC shear walls with monotonic, staggered and cut-out openings; the beams with dapped end; the beams with composites applied laterally or with mechanical fasteners; columns with fibre wrapping and near surfaces mounted reinforcement. For the last two subjects, respectively for the walls with cut-out openings the studies in are in the early stage, the theoretical results being under validation with experimental tests. STRUCTURAL MASONRY WALLS RETROFITTED WITH COMPOSITES The seismic vulnerability of the masonry buildings was obvious during the major seismic events across the world. One of the latest examples was the case of the residential buildings from the town Moldova Nouă, Romania, which were damaged after the earthquake in 2002. A significant number of masonry elements suffered serious damages, and the use of an effective retrofit technique, such as the FRP composites overlays, was needed to increase the in-plan and out-of-plan strength and the stiffness of the masonry walls. The objective was to investigate the behaviour of the unreinforced clay brick masonry walls subjected to in-plan shear loads strengthened with FRP composites on one side of the wall. Thus, several finite elements (FEA) were analysed and five specimens were built and tested. 1 Politehnica University of Timişoara, tamas.nagygyorgy@ct.upt.ro 2 H.I. Struct, Timişoara, histruct@binet.ro