Barmouth Bridge Repairs

In 1980, casings made from Glassfibre Reinforced Concrete (GRC) were used as permanent formwork for casting protective/repair bases to the wooden columns supporting Barmouth Bridge on the west coast of Wales. The original wooden columns had been weakened by Ship Worm.

The GRC casings are in the severest of saltwater environments (the tidal. wet/dry zone) yet, nearly 45 years later, the GRC still remains in good condition and continues to provide an outer protective barrier to the concrete and the wood within.

We hear a lot about the strength and durability of Ultra High Performance Concretes but here is a time tested proof that GRC is also an extremely durable material. Research at the Cement and Concrete Association and elsewhere in the 1980’s demonstrated that 1mm of GRC provided the same protection to steel reinforcement as 10mm of well compacted concrete.

GRC may not be classified as an ‘Ultra’ High Performance Concrete but it’s certainly a type of ‘High Performance Concrete’ when used in applications where durability is critical.