Testing and monitoring

This chapter is intended to provide an introduction to the breadth of testing and monitoring technologies currently available in the UK and to suggest how they might be applied in typical investigations. Visual, non-destructive testing and intrusive methods are covered, all of which may be considered to be special investigations in accordance with the Design Manual for Road and Bridges (DMRB) CS 450 (Highways England, 2021). Each can be used repeatedly to perform ‘monitoring’ for a substandard structure, as per DMRB CS 470 (Highways England, 2020a).

Before considering an investigation, the bridge manager must determine the need for testing and monitoring and convey that to potential providers. If more than one desirable outcome is determined, it is also necessary to prioritise those outcomes. This can prove useful later for all parties involved when selecting techniques, sourcing supplier(s), planning, delivering investigations, reporting, interpreting results and determining actions. Some reasons for carrying out an investigation and related considerations are described below.