Bridge Inspections
The inspection rate is in line with our new County standards that all bridges will have a general inspection every two years and those bridges on the primary and principal routes and other identified major bridges will have a principal inspection every 6 years. This is now in line with the national recommended standard of 2 and 6 years intervals respectively and has been revised as identified in the bridges Best Value review.
Maintenance
All bridges requiring maintenance will be subjected to a risk assessment before money is allocated for maintenance. Although priority is normally given to improving and maintaining structures on the Principal Road Network the limited funds will be allocated where most needed. For example, St. Ives River Bridge is an important ancient monument which justified the continuation of the investigation programme started in 1997. A revised strategy for prioritising bridge maintenance along with strengthening will be implemented as identified in the Best Value review.
Routine Maintenance
Regular routine maintenance is the most cost effective way of keeping our bridge stock in serviceable condition. It involves basic cleaning and servicing, tightening of bolts and unblocking drains. In spite of its importance lack of resources means that there is now a backlog of work to be done.
Emergency and Accident Damage
The most common form of accident damage is because vehicles collide with parapets and the number of incidents is increasing. Where possible the cost of damage is recovered but where new standard parapets are used they absorb the impact and it is often possible for the vehicle to drive away. Old style post and rail parapets offer little protection and a programme of identification, prioritisation and renewal will be implemented in line with the Best Value review action plan as resources become available.
Minor Maintenance Schemes (Under £25,000)
This covers minor maintenance such as concrete repairs, parapet maintenance, and brickwork repairs. Early repair to a small defect normally leads to avoid more costly repairs later. The Best Value review identified the need for resources to be allocated for the work.
Major Maintenance Schemes (Over £25,000)
These schemes cover all aspects of upgrading including total reconstruction. Careful consideration has to be given to expensive repairs or extensions on old bridges as the repair can often outlive the original structure resulting in the sound new work having to be demolished. The alternative is to design the new work for a reduced life expectancy by reducing serviceability factors.
Special Projects
There are some projects which are difficult to classify from an engineering point of view usually they contain a high amenity value and often have artistic environmental elements. In this category are the murals and artwork in subways normally done in partnership with local City/District Councils, Parish/Town Councils, local residents associations, and local schools/youth groups. Although difficult to quantify it would appear that there are considerable financial and social advantages in this type of scheme because graffiti and vandalism is substantially reduced and use of subways is encouraged. Recent projects include the murals at Sallowbush Way subway in Huntingdon and Barnwell Road subway in Cambridge. Refurbishment, e.g. improved lighting, should be carried out at the same time.
Listed Structures
There are 44 listed structures in Cambridgeshire nine of these, including Huntingdon River Bridge and St. Ives River Bridge are listed Grade 1, scheduled ancient monuments. Unlike most bridges that are designed to last 120 years, ancient monuments must be maintained to last indefinitely. Also unlike most bridges which if they were left to become unrepairable they could be replaced these heritage bridges cannot be allowed to fall into this state or they would be lost forever. We must also maintain them in a sympathetic manner both in the aesthetic and functional aspects.
Footbridges
The maintenance of footbridges produces a wide range of problems as the bridges vary from a simple short span to complex multi-span cable-stayed structures over railways. All are vulnerable to vandalism as their light construction makes them easy targets. Softwood laminated timber was used extensively in the past but this form of construction has proved to be particularly vulnerable to rot requiring extensive repairs and reduction in the life expectancy.