An anchored or braced bulkhead is similar to a cantilever structure, but gains additional support
against seaward deflection from embedded anchors or tilted structural bracing on the seaward side. For
this structure, the piles generally only need to be embedded to a depth one and one-half to two time the
height of the wall above the anticipated scour depth. Anchors are usually a row of piles or line of heavy
objects with a large surface area (deadmen) driven or buried a distance behind the bulkhead.
Connections between pile anchors or deadmen and the wall should be wrought iron, galvanized, or other
corrosion-protected steel. Plain carbon steel should not be used for long-term protection. Horizontal
wales at or near the top of the wall laterally distribute the anchor loads. Anchor systems are not well
suited to sites with buildings close to the shoreline because of the distance needed between the bulkhead
and anchors. In that case, brace piles may be used in place of anchors. Figure 11 illustrates cross
sections of cantilever and anchored sheet pile bulkheads.
The type of soil at a site determines the type of sheet piling than can be used. Steel sheet piling
can be driven into hard soil and some soft rock. Aluminum and timber sheet piling can be driven or
jetted into softer soil. An analysis is required to determine the subsurface conditions at a site and should
be performed prior to selection of materials.
The advantages of sheet pile bulkheads are their long and relatively maintenance-free life and their
uniform appearance. Their disadvantages include the special pile-driving equipment and trained
operators required to install them. The equipment is noisy and requires a fairly wide access route with
ample maneuvering room at the site
22
Previous Page
