Comparison of design and application criteria for various methods used in reinforced concrete beam strengthening

Abstract

The design of the buildings to the earthquakes is a very critical issue. Some of existing reinforced concrete buildings does not have sufficient performance in terms of earthquake. These buildings must be demolished or strengthened. Strengthening design is not a simple engineering account but requires deep knowledge of composite material behavior. In this study, the structural advantages and disadvantages of various strengthening types of reinforced concrete beams are investigated. In this scope, reinforced concrete jacketing, strengthening with steel plate, strengthening methods with fiber polymers and external steel tie are investigated in detail. In the numerical part of the study, the effects of these methods are highlighted. In the analyzes, the reinforced concrete jacketing increased the bending and shear strength of the existing beam but the difficulty of this application was found to make it difficult for such designers to be preferred in beams. Also, the addition of new reinforced concrete section to be added to the lower zone of the beam has also contributed to the bending capacity by increasing the useful height of the beam. However, the strengthening with steel plate has a significant advantage in terms of bending capacity or shear and bending capacity and strengthening with fibrous polymer has significant benefit in shear capacity. It is also seen that carbon fiber polymer plates increase the bending strength as steel plates due to high tensile strength. The external wrapping is only useful in shear capacity of beam.