Concrete @ your Fingertips

Externally bonded FRP – Inspection

FRP strengthening systems for concrete structures must be correctly specified for the anticipated loadings and environment. In addition appropriately trained staff must be used to install the materials. It is important that all stages of the process are monitored and that the strengthened structure is inspected regularly when in service.

During installation detailed records should be kept of the materials used and the installation process. Staff should be supervised at all stages. Site trials should be carried out under representative conditions and control samples taken to act as references against which future results can be compared. Samples should be taken and tested at all stages of the installation and dummy strengthening samples installed at suitable locations for later testing.

Routine, visual inspection of the strengthened structure should be carried out at regular intervals (generally one per year). The most significant risks to the FRP in service are fire and mechanical damage. It is important to check that the environmental conditions and applied loadings have not changed significantly. Detailed inspections, with testing, should be carried out at agreed intervals, depending on the type of structure; typically for bridges this will be at a maximum of six years. The instrumentation currently available for testing on site is limited but techniques such as thermography are being developed.

Acknowledgement: The Concrete Society

Concrete Bookshop - Members receive 40% discount on Concrete Society publications

TR57 Strengthening concrete structures with fibre composite materials- acceptance, inspection an