1st Croatian Conference on Earthquake Engineering 1CroCEE 2021

It is a usual practice that traditional methods with traditional materials (most frequently jacketing of elements) are used for repair and strengthening of structures. However, lately, particularly in the last two decades, there have occurred new construction materials intended for strengthening and design referred to as composites strengthened by polymer fibers (CFRP). These materials have special mechanical properties and special properties.
Within the frames of this paper, special emphasis will be put on RC buildings where, during construction, the built-in concrete has not achieved the designed concrete class and/or buildings that cannot satisfy the required strength, stiffness and deformation characteristics, particularly in earthquake conditions. In these cases, it is necessary to take measures for repair and strengthening of both individual structural elements and whole structures. In the paper part of the analytical, laboratory and quasi-static experimental investigations of designed models of RC columns will be presented. Particular attention will be paid to behaviour of these columns under cyclic loads, whereat a number of comparative analyses of a number of parameters obtained from the experimental investigations of the tested models will be carried out. It will be pointed out that the use of these innovative CFRP materials greatly contributes to the strengthening of RC columns and significantly increases the ductility capacity, which is of great importance in seismically active regions. Some recommendations and outcomes will be given as to the approach and technology of practical application of these materials.