REINFORCED CONCRETE BEAMS STRENGTHENED WITH A ROD-ROLLER SYSTEM

Abstract

A system of strengthening reinforced concrete beams has been developed, which allows us to strengthen not only the stretched lower zone under load, but also the upper compressed one. This is achieved by the action of only one flexible steel rod element that connects the compressed and stretched zones of the beam. For the first time it became possible to strengthen the compressed zone of the beam not with traditional massive compressed elements, but with flexible stretched elements of minimal cross-section. For changing the direction of the action of forces on the beam from the compression of the stretched zone to the tension of the compressed zone a system of rollers is used. The adjustment of rolling friction forces on rollers allowed automatical regulation of the balance of forces between the compression of the beam in the corresponding zone and its tension to achieve the maximum effect of strengthening. The article describes the method of calculating the stress-strain state of reinforced concrete beams reinforced with a new external rod-roller system, which allows taking into account the friction of the reinforcement system, actual concrete and steel diagrams, as well as the deformation model of the structure under load. A new system for strengthening single-span reinforced concrete beams of rectangular cross-section using external flexible steel rods is presented. The procedure of strengthening of beams is provided by the system of rollers. The study proposes a method of calculating such reinforced beams. The calculation method considers the loss of tension due to the friction when the external wire is in contact with the rollers. The procedure considers a complete diagram of the work of concrete with a descending branch and discrete linear behavior of steel. The model takes into account the deformation of the structure under load. The paper determines the estimated bending moment for reinforced concrete beams.