Externally bonded reinforcement was first utilised in 1975 on Quinton Bridge on the M5. For this project steel plates were bonded to a concrete bridge using a first generation epoxy adhesive. Steel plate bonding became more common over the next few years and a second generation of adhesives were developed to make application easier and to maximise the long term performance in the typical exposure conditions found on bridges. The technique was adopted by the Highways Agency when they published there document BA30/94 Strengthening of Concrete Highway Structures using Externally Bonded Plates.
In 1996 Composite plates were used for the first time to strengthening part of Kings Collage where an existing roof was going to be turned into a floor by adding another storey. A few years later composite fabrics were used to strengthen concrete columns on Bible Christian Bridge in Cornwall.
In 2000 the Concrete Society Published TR55 Design Guidance for Strengthening Concrete Structures Using Fibre Composite Material, and this has become a recognised standard for the design of composite plate bonding.
The steel plates used at Quinton Bridge have only recently come to the end of there service life, over 35 years after there installation, and been replaced with CFRP plates bonded with the latest generation of adhesives with improved durability characteristics.
Ultra High Modulus (UHM) CFRP Plates have also been used extensively for strengthening metallic structures including wrought iron, cast iron and steel.
Other emerging technologies included
- Near Surface Mounted (NSM) reinforcement for concrete,
- CFRP L Shaped Shear links for concrete structures,
- Fabric Wrap systems using Aramid, Carbon and Glass fibres applied using both the wet and dry application methods.
We work closely with Material Suppliers, Specialist Designers and Contractors for the installation of the above systems.
We were involved in the first installation of CFRP plates in the UK. The writing of both editions of the Concrete Society Technical Report TR55 Design guidance for strengthening concrete structures using fibre composite materials. Have published papers at the Structural Faults Conference.