Handbook for Bridge Inspections - TSP2

6.8 Maintenance Measures -
Extent of Damage
The aim of carrying out maintenance to bridges is to ensure that
the same standards and levels of safety are kept during their entire
planned life.
Agreed Time for
Maintenance
Description of Measures
Alternative Stratigies
Pro cedural Codes
Repairs to Concrete
Maintenance shal l be carried out when the fo llowing three considerations
coincide:
-a) Costs are at thei r lowest point.
-b) The bridge's carry ing capacity ca n be main tained.
-c) Users are afforded adequate safety and access.
Addi tionally, one must ensure that a bridge does not negatively
affect the environment and surroundings in whic h it is situated.
Whenever a Major Inspection uncovers damage which requires
ma intenance (Degree of damage 2), a descript ion of the required
measures and associated cost overview must be drawn up.
Following either a Major or Special Inspection an evaluat ion of the
possible alternative ma intenance strategies can be undertaken in
accordance with the Norwegian Public Roads Administration
Handbook No. 147: "The Management, Running & Maintenance
of Bridges".
The description of the measures to be taken should be based on
procedures which comply with the Norwegian Public Roads
Admi ni stra tion Handbook No. 026; " Procedural Codes - 2, 1997".
The materi al s quanti ties incl uded under the different procedures
should be decided on as much as possible at the bridge location.
The extent of, fo r example, mechanical repairs to a concrete bridge
are decided most eas il y by selec ti ng one or more smaller but representative
areas or test sections. Here one can recordfevaluate the
extent of the different kinds of damage.
If the decision is taken to employ special repair methods such as
the following:
- Re-a lkalising
- Chloride extraction
- Cathodic protective measures
then a simultaneous inspection should be carried Oul for the presence
of surface impuriti es on, for exampl e, metal rein forcement
spacers, nails and binding wires, al l of which could affect the technical
and financial measures adopted. In addition, surface impurities
can have an effect on the surface treatment of the concrete.
Re pairs t o Steel
As with concrete bridges it can also be of interest to undertake surveys
of smaller representative sections of steel bridges showing
Handbook for Bridge Inspect ions 81