Long-term deflection of the reinforced concrete beams strengthened with CFRP
| Author | Affiliation |
|---|---|
| Year | Start Page | End Page |
|---|---|---|
2014 | 1 | 6 |
| URI | Access Rights |
|---|---|
| https://hdl.handle.net/20.500.14911/114576 | |
| Santrauka | Dokumento santrauka/dalis |
Beams were loaded with different intensities of long-term load. The intensity of the longterm load was 43 %, 62% or 78 % of the value of the resistance of the control beams. The resistance value of the control beams was obtained from a short-term load test. Experimental results for strains of compressed concrete and tensioned carbon fiber reinforced polymer (CFRP) layer are influenced differently by long-term load intensity. The intensity of strain increment was unstable during the all periods of the long-term experiment in the compressed concrete, while the strain increment of the tensioned CFRP layer became stable after a particular time period. Comparison of evolution of deflection showed that deflections mostly increased in the first time period, which was approximately 100 days. After this time period, the deflections increments decreased and were similar in all beams. The beams were unloaded at the end of the long-term experiment. The measured residual deflection was larger in the beams that were loaded with the highest long-term load intensity. Destructive load tests were conducted on those beams after the deformation reversal process. The results of these tests show that the steel yielding stresses were reached earlier in the beams with high load intensities than in the control beams. The deflection before the failure was greatest in the beams that were loaded with 43 % and 62 % longterm load intensity. The experimental research showed that without additional CFRP anchorage, shear deformations increased in the bond between the concrete and CFRP. The increment of shear deformations was different. The measured displacement of the CFRP layer was largest when the intensity of the long-term load reached 78 %. Decreased bending stiffness associated with the evolution of shear deformations must be evaluated. A deflection calculation method is proposed. This method takes the influence of shear deformations in the bond between concrete and CFRP into account.