THE SAFETY OPERATION OF BENDING REINFORCED-CONCRETE ELEMENTS, STRENGTHENED BY COMPOSITE MATERIALS

Abstract

The article addresses the problem of ensuring the safe operation of the bending concrete elements reinforced by composite materials. Efficient usage of composite materials based on carbon fibers is not fully researched. In addition, there are no any recommendations for the design of such structures in the current design standards of Ukraine. Composite materials based on carbon fibers of Swiss company Sika (tape Sika Carbodur and canvas Sika Wrap) used the most in Ukraine. Therefore, further experimental data accumulation and analysis of the literature on the subject is topical task.

There was performed research of 12 reinforced-concrete beams with dimensions 2000 x 160 x 100 millimeters. During the first research phase was carried out testing of 8 beams without strengthening. Two of them were tested under single load. Other beams were tested under low-cycle loading using different levels. At the next stage was done strengthening of inclined sections of all beams. And then they were tested in the same way as beams without strengthening. The research found that such strengthening increases the carrying capacity of the beams at least 35%. But to achieve this is possible only provided enough anchoring of strengthening system. Also was found that the safety using of these structures depend on load mode. Another factor that must be considered to ensure safe operation of bending reinforced-concrete elements strengthened by composite materials is to limit the maximum deformation of the outside transverse reinforcement during the design stage.