Japan’s Public Works Research Institute performed an evaluation of 53 fiberglass reinforced plastic hydraulic gates that have been in use for over 30 years with little maintenance. Their evaluation included visual inspection of in-service FRP gates, tensile tests on one FRP gate in use for 35 years, and accelerated weather weathering tests on hand lay up, resin injected, and pultrusion constructed FRP. The research lead the institute to conclude that, “…FRP gates seem to be more durable than steel gates after an equivalent period of time.”
Tensile tests of the 35 year old FRP sluice gate were compared to tensile tests on a new piece of FRP. The results indicated that the submerged portions and non-submerged portions of the gate had an average tensile strength within 11% of new FRP indicating that significant deterioration of the FRP body did not occur in 35 years.
The results of the durability tests indicated that aesthetically the surface of FRP gates may lose glossiness over time due to UV exposure but the FRP’s strength remained virtually intact. Furthermore, the study concludes, “…that FRP is especially suitable for hydraulic gates, usually submerged in water since they have excellent durability and water or corrosion resistance”. The report as presented at the Third International Conference on FRP Composites in Civil Engineering in 2006 can be downloaded from our Resource Center in the “Fiberglass Reinforced Plastics (FRP) – Corrosion in Wastewater Systems” section.