such size as will square to 12 inches; they are to be hewn on the two
meeting sides, so as to present a flat surface to each other of at least 10
inches wide on an average. They are to be driven quite close together, as
far into the bed of the river as it is possible to drive them with a pile
driving machine having a rammer of from 12 to 15 cwt. and falling from a
height of 25 feet at least, and when driven thus far, the piles are to be of
such length as to leave 5 feet at least, above the ordinary height of high
water mark of spring tides.
2. On the outside of each row of piles there is to be a string piece of pine
timber of 9 inches square, fixed about 2/4 feet from the top of the piles,
and to run horizontally for the whole length of the embankment. Opposite
the centre of each pile there is to be an auger hole of 1 V* inches in
diameter bored through the string piece and pile, and a white oak trenail
of sufficient size driven quite through them both. The different pieces of
timber used in the string pieces are to be joined by a scarf overlapping 18
inches at least.
3. In every 10 feet of length in the embankment, there is to be a cross
piece sufficient in length to extend from outside to outside of the string
pieces, and to project therefrom at least 12 inches at each end; these
cross pieces or braces are to be of timber that will square 12 inches, and
to be notched 6 inches deep, so as to embrace the heads of the piles
upon which they rest, and the outside string pieces. Immediately on the
upper side of these cross pieces is to be laid a string piece of 9 inches
square, along the inside of both rows of piles for the whole length of the
embankment, and to be fastened to the head of each pile by a trenail as
described for the outside string pieces.
4. The whole of the space on the inside of the piling is to be filled up with
earth flush to the underside of the cross pieces, and in executing this part
of the work, the contractor is to carefully arrange the soil, so as that part
of it which is of a vegetable consistency may be put nearest the piles on
both sides; the intermediate space may be filled up with such soil as can
be conveniently obtained.
Specification for the Jetties
5. The Jetties are to consist of a single row of piles of 9 inches square,
driven firmly into the bed of the river, at the distance of 10 feet from each
other. Each of these piles is to have a tenon at the top of three inches
thick, 10 inches wide and 6 inches long. On the top of these piles is to be
placed a capsill, 10 inches square, with mortices on the under side for the
reception of the tenons on the piles, there is to be a trenail of sufficient
size to fill an augur hole one and a half inches in diameter, to be driven
through the capsill and tenon; the upper side of this is to be on a level
with the ordinary height of high water of spring tides.
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