T0458 AD NW PTSI 23/24

Post tension bridge design is recognised as having critical components, such as cables and anchors, that are hidden from the view of structure owners and maintainers. These components have a brittle mode of failure and so loss of strength can be instant, so it's important that these hidden details are investigated for safety reasons and where possible, monitored. This task centres on the investigation of a number of bridges with post tension design located in Area 10. The bridges included have been prioritised based on HE policy document CS 465.

NH conducted an exercise which conclude in March 2021 which identified the priority of PTSI structures through structures rankings. Out of that priority list some structures were identified as being due for a PBI in 2021/22 which will be carried out by HE's Structures Inspection Contractor, Up and Under (U&U, see Section 525.1). These PBIs will cover any PTSI defects. Based on these PBI findings and the desktop study from this task, the successful SPATS contractor is required to produce:

o a combined Risk Review,

o a Risk Assessment and

o Risk Management Plan report in accordance with CS465.