Test results and strength estimation of R/C beams strengthened against flexural or shear failure by the use of SRP and CFRP

Abstract

The paper reports tests on three groups of reinforced concrete (R/C) beam full-scale specimens, strengthened in flexural or shear using Steel Reinforced Polymers (SRP) and Carbon Fibre Reinforced Polymers (CFRP). The first group of five specimens represents the middle part of the span of a continuous beam and specimens are flexurally strengthened. The second group represents the support region of a continuous beam and its four specimens are strengthened in flexure. The third group also represents the support region of a continuous beam and its four specimens are strengthened in shear. Four specimens in total are tested unstrengthened to allow comparisons with the response of strengthened specimens. In addition to the different part of the beam that each specimen represented and the shear or flexural strengthening, the main parameters that varied among the specimens were: the type of polymer (SRP of two different types, or CFRP), the type of steel bars (ribbed or smooth, the latter being representative of older R/C members), the type of anchorage used for the polymers, and the way loading is applied to the specimens. Low strength concrete grade is used for the specimens, again to simulate older R/C members. The recorded response of the specimens is presented and discussed, and the experimentally measured strengths of the specimens are estimated analytically on the basis of the measured deformations of the specimens. Finally conclusions are drawn regarding the relative performance and merits of SRPs and CFRPs as strengthening materials for R/C beams.