Flexural Assessment of Blast-Damaged RC Beams Retrofitted with CFRP Sheet and Steel Fiber

Abstract

This study presents the effects of blast-induced local damages on the flexural strength of blast-damaged and repaired specimens. In the experimental program, blast-damaged specimens were repaired with steel fiber reinforced cementitious composite (SFRCC) as well as carbon fiber-reinforced polymer (CFRP) sheets and tested for flexural strength measurements. The test parameters included shear reinforcement (amount and spacing), steel fiber content (0, 1.0 vol%), and retrofitting with CFRP sheets. The test results indicated that the use of higher amounts of stirrups demonstrated insignificant benefits in preventing local damages. However, it was shown that the use of small-diameter steel bars for stirrups with small spacing could decrease the local damages more effectively compared to the large-diameter steel reinforcement. For the residual strength of the damaged specimens, the specimens using more stirrups could resist over 60% of their original flexural strength. CFRP retrofitting showed insignificant enhancement in ductility of intact, damaged, and repaired specimens. However, it distributed the blast load and protected debris scattering. The addition of steel fibers results in increased ductility and enhanced blast resistance against local damages. All specimens, excluding control specimen, that repaired with SFRCC showed higher flexural strength to their original strength. Therefore, it can be concluded that replacing damaged concrete cover with SFRCC is adequate for repairing the blast-damaged RC members.