redline

Maintaining structures
The term ‘structures’ includes bridges, culverts, retaining walls, sign gantries, high mast lighting and CCTV poles.

Under the contracts, the OCs must inspect structures (see figure 21) at two and six-yearly intervals and prepare programmes to manage and maintain them. The inspection of some major structures, such as A898 Erskine Bridge and A9 Kessock Bridge, are carried out on a year on year rolling programme.
The OCs then design, procure and carry out works either directly, or by works contacts. The OCs must also monitor sub-standard structures and update Transport Scotland’s bridge database (TRBDb).

Management and maintenance of the Forth and Tay Road bridges are not part of the OC contracts.

2.2.4 Structures

Maintaining Structures

During the year the OCs were responsible for managing a total of 5,627 structures on the network on behalf of Transport Scotland. These structures range from major crossings, such as at M8 Kingston Bridge in SW and A87 Skye Bridge in NW, to culverts carrying watercourses under roads. Of these structures, 1,962 are bridges or footbridges.

A breakdown of the type and number of structures in each Unit, as extracted from TRBDb, is shown in figure 22.


Figure 21 Underbridge inspection vehicle in NW
Unit
Bridges
Footbridges
Other structures
Total
NE
315
17
311
643
SE
339
16
347
702
NW
595
60
1,700
2,355
SW
569
51
1,307
1,927
Total
1,818
144
3,665
5,627

Figure 22 Number and type of structures in each Unit
Unit
Structures Budget
£m
Structures Spend £m
NE
1.38
1.23
SE
3.08
2.70
NW
6.00
6.22
SW
11.02
11.98
Totals
21.47
22.13

Figure 23 Comparison of structures budgets
against spend

In 2007/08, structures spend was £22.1m representing 13% of overall spend. This represents a slight reduction from the total spend of £22.3m in the previous year. Allocation of budget is based on network need and reflects the age and condition of the structures, as well as traffic volumes.

Over 50% of the budget is spent in SW.
A comparison of spend against budgets for structures is given in figure 23, and shows that spend was within 3% of
total budget.

Inspecting structures

Regular inspection of structures to monitor and record their in-service condition is one of the OCs’ major responsibilities.

Of the 5,627 structures across the network, 4,135 require principal inspections every six years. In addition, the OCs undertake general inspections
of structures every two years and superficial inspections.
redline