The Ouachita telegraph. [volume] (Monroe, La.) 1865-1889, 1882-01-27

caissons, large piles were driven as far
down as possible and as thick as the
circumference of the cylinder, about
nine feet, would allow. On these piles
heavy sawed timbers were fastened,
and upon these timbers the masons be.
gan work, filling the caissons to the tsp
with hard brick laid in hydraulic c.
| ment.
The same process was followed with
the western shore piers, but these are
some smaller than those on the oppo-
site shore. These piers are capped with
a solid circular block of Missouri gran
lite upon which rest heavy iron plates,
and on these rest the abutments. The
cylinders we're shipped to this point
from the foundry In half circles and
were riveted in sections on the ground,
the quick strokes of the hammers az
fording fair illustration of the music
of foundry.
1t may sound rather odd, but the
abutments of the bridge are not i'm
movable or fastened to the piers. Small
iron or steel rollers, thirty inches in
length, are fastened to the abutments
and these rest ON the iron plates
above mentioned. The reason for this
mobility is quite self-svggestive, to-wit:
allowance must be made for contrac-
| ton and expansion of the iron forming
the span, necessarily resulting from
differences in temperature of the wealth
er. The extreme difference between
expansion and contraction in span No.
1, length 243 feet, is estimated at one
and one-quarter inches.
The summer of last year opened pro-
pitiously for putting the main river
piers in position. The plan of building
these piers was the same as to each of
the four, numbered respectively, going
west, two, three, (the draw pier,) four
and five. The bed of the river at the
points indicated was dredged or exca-
waited to level, and the piers were
built on the caisson plan. Mattresses,
made of pieces of sawed timber cross
ing at right angles, leaving insterstices
through which the piles were to be
driven, were first sunk in place. Be-
| tween the framed pieces of timbers
crossed, of which there are two, an up
per and lower, brush was placed, and
the two frames were then firmly pinned
together. A barge floating pile-driv-
or and steam engine was brought into
position and the Work of driving the
piles proceeded, most OF the time day
and night, there being two sets OF
hands employed. The piles were driv.
en- to depth ranging from thirty to
forty feet, according as the resistance tc
the ponderous hammer, which weighs
$500 pounds, next to the heaviest used
in such work in the United States,
showed. that further blows were OF
were not required. This part of the
work was tedious and tying, as the
piles had to be driven through closely
packed sand the full depth, except
about twelve feet below the surface
where strata of clay and gravel,
which only augmented the resistance,
pierced. 1t was remarked by Super
intendent Houser that in driving a pile
at pier five the huge hammer, falling q
distance of thirty feet, rebounded from
the head Of the pile fully three feet
1t was found necessary to pump water
from the river through hose termin.
ating with a nozzle at the point of the
piles and following them as driven, ir
order to loosen the sand and make the
driving possible.
The piles driven, they were Their
sawed Off to a common level Mt the
top, and upon the foundation thus
made, heavy grillage timbers, two fee
thick, were laid. ITO these timber.
were secured the caisson castings, which
are of three-eighth inch boiler iron ant
nine feet high. Inside these caissons
the masons began laying the brick, al
of which were subjected to close inspec
ton, and are laid in cement. Some O
, the piers are capped with limestone
, with granite super-imposed as "a rest fo
3 the ends of the spans.
| THE SUPERSTRUCTURE
is, with the exception of the wooder
I ~, ,,.f