Untreated Logs. Horizontal untreated logs can also be attached to the-landward side of posts.
This is particularly advantageous in areas such as the Pacific Northwest, where there is an abundance of
logs. The same precautions about adequate toe protection and filtering also apply, since large gaps
between logs make adequate filter design more difficult. If a cloth is used, it should follow the log
contours so that it is not excessively stressed by bridging the large gaps. Filter cloth is vulnerable to
damage or vandalism, however, which would jeopardize the entire structure with the resulting loss of fill.
For that reason, the use of logs is probably more risky than use of treated timber.
Used Rubber Tires. Used tires can be strung over two rows of treated pos s set in a staggered
pattern, with the tires abutting each other and filled with gravel. The posts are tied back to logs buried in
the backfill, with filter cloth placed behind the tires before backfilling. Under wave action, the gravel
tends to wash out of the tires, and the backfill can then escape. Although used tires can generally be
obtained free, the structure is probably comparable in cost to other post bulkheads because of the
required close spacing of postholes. This kind of structure is generally not recommended.
Steel H-Piles and Railroad Ties. Steel H-piles can be used as posts with railroad ties placed
between their flanges (Figure 16). The toe should be protected by armor stone, and proper filtering and
granular backfill are needed behind the structure. A 12-inch steel channel, welded to the top of the H-
piles, aligns the piles and protects the timber ties. While the structure has performed well and would be
useful where bedrock prevents driving sheet piling, its cost is higher than other potentially effective
devices.
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