RESEARCH OF THE STRESS-STRAIN STATE OF REINFORCED CONCRETE BENT ELEMENTS STRENGTHENED WITH COMPOSITE MATERIALS

Abstract

The use of new technologies in all areas of production, re-planning and conversion of premises, increasing the load on structures and the load-bearing capacity of structures require special attention to the problems of reconstruction of buildings and structures. The renewal of fixed assets does not involve the replacement of building structures, but leads to the effective use of existing buildings and structures. However, many building structures are subject to physical wear and tear, so during the reconstruction of buildings and structures, building structures are restored or strengthened. One of the modern methods of strengthening is the use of composite materials. The paper presents the results of changes in the stress-strain state of reinforced concrete beams reinforced by a system of composite high-strength fibers based on P.B.O. FRCM. The advantages of these materials are high static and fatigue strength, a modulus of elasticity close to that of metal, low own weight, lack of dimensional restrictions and joints, the possibility of connection with a reinforced structure only due to glue, a short period of work, low labor intensity and cost, and also high corrosion resistance, durability and reliability, as composites are inert to aggressive environments. At the same time, since it is sometimes difficult or impossible to unload during the strengthening of the structure, the reinforcement of the experimental reinforced concrete beams was carried out at 50% of the bearing capacity of the control unstrengthen samples. The destruction occurred due to the fragmentation of the compressed concrete zone. At the same time, the delamination of the mesh continued in the direction of the supports, but complete delamination did not occur. The crushing of the concrete was smooth and gradual, which indicates the plastic nature of the beam failure. As a result of reinforcement of reinforced concrete beams with the Ruredil X Mesh Gold system, the cross-section is stiffened due to the inclusion of reinforcement elements in the work. The bearing capacity of strengthened reinforce concrete beams has increased by 25% compared to unstrengthen ones.