Investigation on flexural performance of cracked concrete beam strengthened using CFRP with intermediate anchors at cracked locations

Abstract

The flexural performance of heavily cracked reinforced concrete (RC) beams strengthened with different carbon fibrereinforcedpolymer(CFRP) arrangements was investigated. In total twelve CFRP-strengthened and non-strengthened RC beams with a span of 1900 mm were tested. : Initially, a transient load was applied to the non- strengthened beams until 3 mm wide cracks appeared. Load versus deflection was monitored. The wide cracks were filled using a high-pressure epoxy injection prior to strengthening. CFRP sheets were epoxy bonded to the tension face of the beams and CFRP U-strap anchors were introduced at discrete locations to mitigate both end and intermediate span debonding. All specimens were tested using a four point 1 bending configuration. On average, an 80% to 118% increase in flexural capacity was noted for | the pre-cracked and repaired strengthened beams and the average strength gain noted for noncracked beams strengthened with CFRP was 37%. Cracked beams strengthened with CFRP with polymer U-shaped anchors showed optimum performance. De-bonding was the dominant failure mode in most tested specimens.