Figure 6.9. Steel jacks.
6.4.8 Bulkheads
Bulkheads can be used to prevent streambank erosion or failure. As an additional benefit, a
bulkhead may provide a substantial increase in waterfront area and an improvement in
water/land access. Concrete, steel, timber and more recently, aluminum, corrugated asbestos,
and used tires have been used to construct bulkheads. Concrete and steel bulkheads
generally cost at least four time as much as a comparable bulkhead of another material;
however, the service life is longer and less maintenance is required. Timber is the most
commonly available material for economical bulkhead construction.
Timber bulkhead construction is similar to common fence construction except that a few
precautions should be observed:
All wood should be treated with preservative to minimize deterioration due to repetitive
wetting and drying or insect activity.
The toe of the bulkhead should always be protected with riprap. The most common cause
of bulkhead failure is scour around the pilings, followed by the structure tipping over due to
the pressure of the bank behind the bulkhead.
Piles should be anchored to deadmen buried in the bank.
Fill material placed between the bulkhead and natural bank should be free draining so that
the soil behind the bulkhead will not become saturated and push the structure over.
If there are no cracks between the planks, weepholes should be drilled in the fence at
regular intervals to allow the bank to drain. Filter fabric or gravel can be placed as a filter
behind openings in the fence to prevent fine soils from leaching through. A filter must be
properly designed to match the filter with the soil.
The bulkhead should be tied into the bank at the upstream and downstream end of the
structure to prevent flow behind the bulkhead.
6.17
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