We are responsible for the maintenance of around 4,000 highway structures.
This includes:
- 1516 bridges
- 141 footbridges
- 2206 culverts
- 148 retaining walls
- 14 subways
- 10 gantries.
As new highway infrastructure is built, more assets are being added to the list.
Inspections and maintenance
Routine inspection
We conduct general inspections on all structures to assess the condition and the extent of any significant change - or deterioration - since the last inspection and to record any information relevant to the stability and continual use of the structure.
- General inspections of brick or reinforced concrete culverts, bridges and walls retaining more than 3 metres are carried out every 2 years.
- General inspections of corrugated steel or concrete pipe culverts and walls retaining more than 1.37 metres in height are carried out every 6 years.
In addition, principal inspections of bridges with spans greater than 5 metres are carried out every 6 years. Where access is difficult or dangerous, CCTV and high-resolution digital photography or video can be used.
‘Principal inspections’ mean a close examination, within touching distance of all accessible parts of a structure. This can include underwater parts, adjacent earthworks and waterways.
Principal inspections can also be carried out for bridges with spans less than 5 metres, subject to risk assessment. These principal inspections will establish the scope and urgency of any remedial or other actions required before the next inspection.
They also show the need for further investigation or a special inspection and the accuracy of the main information on the structure held in the inventory. A ‘Special Inspection’ concentrates on the condition of a particular part of the structure.
Routine maintenance
We have an established routine maintenance programme for highways structures. This includes:
- Planned routine electrical, hydraulic and mechanical maintenance of moving bridges like Cross Keys Swing Bridge on the A17.
- Planned routine electrical and mechanical maintenance of pumps used to drain subways.
- Minor maintenance generated by inspections and third-party reports.
Planned maintenance
We use asset inventory, condition and relevant data to determine the current performance of highways structures and to plan their maintenance.
View our Highway works programmes.