Evening star. [volume] (Washington, D.C.) 1854-1972, 1873-03-29

SOMETHING ABOUT THE OLD BRIDGES AT THE
LITTLE FALLS, AND A DESCRIPTION OF TIE
NEW STRUCTURE TO BE PLACED THERE.
The new iron bridge over the Potomac, on the
site of the Old Chain bridge, near the Little
Falls, about four miles above Georgetown, will
be erected this summer. When finished, il will
be one of the most substantial structures in this
vicinity. Several spans of the wooden truss
bridge at this point were washed away by the
great freshet three years ago, IL will be remem-
bered, and since that time q great part of the
travel which formerly passed over IL has been
private affair. and exacts exorbitsM tolls from
all using it Two OF the spans of the bridge
those over the channel Of the river-were left
when the freshet took place, but are in a very
dilapidated condition, and from these an in
clined plane was constructed TO the low grounds
some twenty-five or thirty feet below, where a
rough roadway was made. and light vehicles
have been enabled to cross though it could not
be used for heavy loads. The piers upon which
the wooden bridge rested were built some years
ago, by the government, in the most substan-
tal manner, and are just as perfect as ever, and
likely To endure Tor ages.
THE NAME CHAIN BRIDGE"
has been applied to the successive structures
there, because the first bridge erected there,
more than half a century ago, was a chain sus-
pension bridge. Since its destruction by
freshet, numerous wooden bridges have shared
the same tate. The want Of suitable bridge
locality, on botn sides of the river, for some
time, and year ago Congress made an appro-
priatioR of sl0e.ec0 TO construct q suitable iron
bridge on the site, though not without great
opposition on the part of the Aqueduct Bridge
company, whose tolls will be considerably les
sened by the opening of the new bridge. The
construction Of the new work was put in charge
of General Babcock, Superintendent of Public
Buildings and Grounds, whose known ability as
an engineer is q guarantee that the government
will get the very best bridge that can be placed
there for the amount appropriated. Last fall,
after receiving numerous bids and examining
various designs. he awarded the contract for the
structure to Mr.. s. r. Dickson, OF New Haven,
Conn.,, for the sum of $9s SIS.
THE DIMENSIONS OF THE NEW BRIDGE
will be ,352 feet long and 20 feet wide. IL viii
be composed Of six spans of l12 feet each and
two of leo feet each. Ii will rest upon the piers
now standing, though it will be two feet higher
than the old bridge and preparations are now
being made to place additional layers of stone
height fhey are ssfonS enough to resist te
heaviest freshets. They rest upon found ations
of solid rock and there need be mo fear of the
made entirely of wrought iron and its genera enc
form will be that known as the tubular truss
bridge. 1t will be Of rolled plates, angle, bar
be Is feet below the upper ONES, making the
height Of the bridge from the floor to the TOP
16 feet, sufficient for the largest load to pas
between: Between the upper and lower chords
there viii be three systems of vertical posts
and diagonal braces. The upper and lower
chords will be of rolled plate 20 inches wide and
between the lower chords supporting the floor OF
ttS % VII. 1 eSsi.ata az Sr.i~r- al Ai-ieet.
plate iron placed at intervals Of about ~ feet.
The floor beams to rest on these iron Orders are
to he Of the best northern white pine IA inches
I'm depth, IN width and 25k feet long On
these moor beams will rest ten rows of stringers
OF white pine 10y inches and on these beams
the foor of the bridge of white oak plank 8
inches thick and inches wide will be securely
spiked. All the riyeting in the iron work must
be hot riveted and the iron ok will be covered
with two coats OF paint. At each end Of the
bridge there viii be an ornamental wrought
iron portal: A great part of the iron work has
been completed At the factory in New Haven.
ana the labor OF putting il up would have been
commenced before this had there been any
could have been transported to the bridge.
They are all ready for shipment, and the canal
now being full, work will be commenced in the
course OF few days. The contract called for
the completion of the work by the LIST OF June.
but, on account OF the delay, which could not he
avoided, the structure will not be Completed
until later in the summer.