Evening star. [volume] (Washington, D.C.) 1854-1972, 1871-10-21

two abutments, all built OF cut sand stone nom
Freestone Point and blue gneiss from the quar-
ries above Georgetown.
THE MANNER or CONSTRUCTING THESE PIERS
mas been described heretofore In The STAR
They resi- on cluster of piles driven into the
bottom OF the river ss far a. they will 90. In
each OF these clusters there are from one 20 two
hundred piles These are sawed OF about three
rect below water by means OF an ingenious steam
saw attached 70 vertical shaft which NAV be
iet uoNner taken up at pleasure. This is driven
py steam engine and the necessary machinery
attached, all being fixed upon a Sow which
may be moved about in different places wherever
desired. When this cluster of piles have Ali he
sawed on, crib of Pinch solid oak timber i
sunk down TO cover the tops of the piles. forming
a Gaping, and bOlted down with heavy iron
spikes. This timber IL, of course, never exposed
TO the air after IL Is once sunk and upon il re- T.
the foundation for the piers, which are built IN
nine feet above low water, making them two a. =
higher than the old bridge, which was only sev, =,
feet above low water mark.
THE sUPKRsTRUcTURE.
The space between these piers is ahout no
leeb which Is spanned by immense wood string
ers of heavy Susquehanna white nine Wha1f
timber, and nicely framed together before they
are raised 10 their places These rest upOn wall
plates made OF oak timber ten inches s1nara
Ihe stTlngers are sixteen inches square and
each joint, wherever made, is thoroughly coated
with white lead and oil before being Joined to-
gether From these cords or stringers rises the
superstructure, which Is OF the best timber.
t hrmy bolted together, all forming what is
known as
THh HOWE Truss BRIDGE.
Inc piers IN the two channels of the river are
oHals, with transverse diameter of "a feet the
piles being driven TO conform 30 the shape of the
piers. These pile foundations will be sunk eight
Ieet below the tide, and on the top the trans
verse diameter will be about six feet The
length OF these piers, not including the channel
plers, are "A feet, about eight more than the
width OF the bridge, including the railway and
roadway. The span of draw in the washington
channel is 81 feet, and in the Virginia channel
Soy feet.
THE OLD cAusEwAY
mas been entirely removed and a new one con-
structed, with the walls of solid stone ma onry
nIed between with earth and gravel. Its length
Is $50 feet, and il has been raised about i've
rect higher than the old one, giving the bridge
much more elevated and imposing appearance
than formerly.
The flooring Of the bridge is to be of the best
oak or gum plank, and il is thought the wood
work portion OF the entire bridge will be covered
IN with roof 70 protect il from the weather
The superstructure 10 now fast approaching
completion, four-ffths Of the work being already
done, and by the first of December il is expected
the roadway will be open TO public travel. A
large force of men are at work, some five hun
dred, IN different capacities, and large mum
Der at the stone quarries.
THE COST OF THIS WORK
Is estimated by the resident engineer, G. W
Domer, 10 be upwards of a million of dollars or
over two-tlirds more than the cost Of the old
bridge TO the United States during the time of its
possession by the government.