Environmental Engineering Reference
In-Depth Information
Figure 15.19.
Salvajina Dam perimeter and near abutment vertical joints (ICOLD, 1989a). (1) Hypalon
band, (2) Mastic filler, (3) Compressible wood filler, (4) PVC waterstop, (5) Copper water-
stop, (6) Neoprene cylinder, (7) Styrofoam filler, (8) Sand-asphalt mixture, (9) Zone 2, (10)
Steel reinforcement, (11) Steel reinforcement to protect concrete against crushing and to pro-
tect waterstop. (A) Face slab, (B) Perimetric joint, (C) Plinth, (D) Plinth, (E) Face slab, (F)
Abutments.
steel, jointing consists of a lap joint fixed by spot welding, then sealing by tungsten-inert
gas welding, so that only one metal is involved.
Pinkerton et al. (1985) indicate that in their experience the limit of shear displacement
of “W” type primary water stops is around 7.5 mm, up to 50 mm for a 230 mm centre
bulb rubber water stop and 10 mm for a PVC waterstop.
Centre bulb water stop.
These are constructed of PVC, natural rubber or hypalon.
Fitzpatrick et al. (1985) indicate that they prefer hypalon rubber instead of natural rubber
or PVC because natural rubber in the atmosphere must be protected from oxidation and
ozonation by the addition of antioxidants and antiozonants which could leach out. These
materials will last indefinitely below minimum operating level where permanently sub-
merged, but there may be a problem between minimum operating level and flood level as
PVC contains plasticizers, some of which are known to leach out.
Pinkerton et al. (1985) indicate a preference for hypalon rubber because it can accept
much larger deformations as detailed above.
