Abstract
Previous studies demonstrated that significantly cracked beams can be repaired by bonding
steel plates, however, there is a lack of comprehensive information about the effect of the
width-to-thickness ratio of steel plates on repaired composite beams, and the use of thicker
plates to repair failed RC beams. This paper presents an assessment of the performance of precracked
reinforced concrete beams repaired with adhesive bonded steel plates, of varying
width-to-thickness ratio, at the soffit. A total number of 12 beams were tested under a twopoint
static loading. Group 1 consisted of two control specimens, Group 2 comprised of five
beams that were pre-cracked to 60% (serviceability load), and Group 3 consisted of another
five beams that were pre-cracked to 85% of the ultimate load. Subsequently, the pre-cracked
beams were repaired by bonding steel plates of 6 mm thickness and 75 – 175 mm widths, which
varied in increments of 25 mm. Externally bonding steel plates to pre-cracked reinforced
concrete beams increased their load capacities by more than 100%, compared to the control
beams. Except for specimen PB60-175, there is generally increase in the capacity of the
repaired beams with increase in the width-to-thickness ratio of the steel plates. Beams that were
pre-cracked at a lower load level (serviceability load) reached higher strengths than the beams
that were pre-cracked at a higher load level (85% of the ultimate load capacity). In all tested
beams, the experimental moment of resistance did not reach the code-predicted moment of
resistance, calculated using EN 1992-1-1.