Fatigue Flexural Behavior of RC Beams Strengthened using GFRP-Sheet After Seawater Immersion

摘要

Bridges or docks on coasts often fail due to fatigue loads. Sea waves striking bridge or the dock give a fatigue effect to the structure thus accelerating structural failure. This study aims to analyse glass fibre reinforced polymer (GFRP) reinforcement on reinforced concrete beams under fatigue and monotonic loads influenced by sea water. One normal concrete flexural beam (BN) with repetitive load was without seawater and no reinforcement. One flexural beam was without seawater immersion but with GFRP-reinforcement. Another flexural beam reinforced by GFRP sheets is immersed in a pond containing seawater with time variations up to twelve months. The results showed an increase in capacity due to GFRP-reinforcement. There is a decrease in the capacity of GFRP sheet influenced by seawater immersion. The same trend with the decrease in ductility occurred in the flexural beam to seawater immersion. The failure occurring in the flexural beam was preceded by the failure of the attachment between the concrete and the GFRP sheet at the load centre (mid of span) slowly to the support until failure (debonding) initialized. The GFRP-S bonding capacity to the concrete skin has decreased in twelve months. Therefore, there is a significant effect of decreasing strength due to seawater immersion.