During replacement of a valve on an intake pipeline, a large reinforced concrete thrust block was to be subjected to a design force of 120 tonnes. An assessment of the element’s structural capacity raised concerns about the adequacy of the steel reinforcement to resist the force.
Tony Gee proposed a solution reinforcing the block with a CFRP composite bonded to the external tensile faces. Using the wet lay-up technique, up to four layers of carbon fibre were aligned in a quadraxial fashion, each layer being impregnated with a low viscosity epoxy resin.
The CFRP composite design overcame the difficulties that would have been encountered installing conventional heavy steel props. In addition to providing a safer solution at lower cost, the CFRP composite can remain in place with no impact on the available working space for future maintenance.