Handbook for Bridge Inspections - TSP2

6. Measuring the actual cover to check the cover meter
7. Re-filling
Cutting into concrete can also be carried out in connection with the
assessment of the scope of corrosion to the rei nforcement elements.
Barriers should also be cut open to assess the reduction in
cross-sectional reduction of the reinforcement. Areas showing
visible signs of surface corrosion of the concrete should be approached
in a similar fashion. This is especiall y desirable for
barrierslthe results of corrosion which are found in areas prone to
static strain.
Equipment
* Cutting equipment (chisel hammer)
* Camera
* Slidc callipcr
* Magnifying glass
* Wire brush
* Materials and equipment for refilling holes
7.3.9 Location of Materials Testing for
Concrete Coastal Bridges
Chloride Penetration
It has become apparent that chloride penetration on exposed coastal
bridges is characterised principal ly by three sets of circumstances:
I. Height above Sea Level: Chloride penetration increases
according to the he igh t of the superstructure above sea level ­
refer to Figures 7.3- 18 and 7.3- 19. The same applies to co lumns
(see Figure 7.3-20). However, in some instances the chloride
contem has been shown to be lower further down the columns
than nearer the top.
2. The Windward/Leeward Effect: Chl oride penetration is mar
kely greater on surfaces subject to wind and rainfa ll on the lee
ward side. The effects can depend on their being/not being sub
ject to rain and negative pressure on the leeward side resu lting
in sea spray settling on the concrete surfaces - refer to Figures
7.3-18and 7.3-19.
Leeward facing surfaces are to be found on both the sub and superstructures.
The following are some typ ical examples:
* Vertical surfaces in the lee of wi nd and ra infall (columns, webs
in box gi rders and beams.
* Horizo ntal downward fac ing surfaces - the undemeath of top
cross-beams, beams, top plates and wings, and base plates of
box girder bridges.