Civil Engineering Reference
In-Depth Information
Figure 13.36: Bulwark method of foundation work. Source: Drange, 1980
causes pollution of the surrounding earth and water. Surrounding the timber with
clay also helps.
Timber-based methods of foundation work
Bulwark
This technique has been used since the Middle Ages, especially when building along
the edge of beaches and by farms. It is basically a structure of logs laid to form a
square and, cut into each other at the corners, 2-3 m on each side. This form is then
filled with stones to stabilize it. Bulwark has an elasticity in its construction which
allows it to move, and it can therefore cope with waves better than stone or concrete.
If the right solid timber is used, a bulwark can keep its functional properties for hun-
dreds of years.
Raft and pile foundations
Many large coastal towns are built on raft or pile foundations. If the foundations are con-
tinually damp, then the durability is good. Excavations have discovered pile foundations
of alder and aspen from the Middle Ages which are still in perfect condition, with even the
bark of the tree preserved (Lidèn, 1974). Through the increase of tunnelling and drainage
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