Civil Engineering Reference
In-Depth Information
d) Hollow kerbs
A commercial version of the trough is the hollow kerb. This is an effective if expensive
system. It may be combined with a carrier pipe as described above. Lengths of hollow
kerb may be used to solve diffi cult problems at low points or where crossfall reverses.
e) Piped system in beam bridges
In bridge decks consisting of multiple precast beams, it may be possible to arrange
the beams such that the gutter is located between beams, Figure 9.43 (a), ideally in
the cast-in-situ slab. The gullies may be associated with conventional silt traps, which
are emptied from the road as if it were at grade. A piped system may then be located
between the beams, taking the water off the deck. It may be necessary to provide a
suspended walkway giving maintenance access to the silt traps and pipe-work.
If it were not possible to locate the gutter directly over a suitable position, gullies
without silt traps would discharge into the carrier pipe with a short access pipe,
Figure 9.43 (b). Silt traps could be located opposite each gully, or at the bridge ends. It
may be necessary for the precast beams to incorporate some of the drainage hardware,
which emphasises how important it is to consider, and even to design in detail, the
drainage system early in the design process.
Figure 9.43
Piped drainage in precast beam deck
