Flexural strengthening of pre-cracked RC slabs with prestressed NSM CFRP laminates and evaluation of strain loss

The strengthening intervention of RC structures often involves already cracked concrete. To evaluate the effect level damage prior to (pre-cracks) on behavior flexurally strengthened slabs with prestressed NSM CFRP laminates, an experimental research was carried out. Two pre-cracking levels were analyzed and, for each one, three prestress tested (0%, 20% and 40%). obtained results showed that damaged laminates in a significant increase load carrying capacity at serviceability limit states. Pre-cracked presented almost similar corresponding uncracked slabs. determine effective variation strain over length time experimentally recorded. transfer also evaluated. revealed less than 150 mm, maximum value loss out (around 14%) measured close section Significant part occurred during 24 h after releasing load.