The intelligencer. [volume] (Lexington, Mo.) 1887-1891, 1888-12-22
THE NEBRASKA CITY P0NTOON
BRIDGE.
From the Scientific American.

From the Scientific American.
We illustrate in the present Issue
new bridge recently completed, which
crosses the Missouri river at Nebraska
City, Neb. The bridge is of a type
that has been but little used, except for
military purposes. 1t consists of floor
ing carried by substructure which -
hoats upon the river A,similar bridge -
across the Rhine, betsHfeol f5Skaeni land
Ehrenbreitstein, vii 81. = ~ = !.
by our readers, whe1 De $|56I u + -.
ried by series OE< {4C
A pOntoon bridge H.
the Mississippi river a. "a.
Chen. In military operationt ~ IL
bridges, from their portability, and f61
account of the rapidity with which
they can be put together, have acquir-
ed much Importance, and have figured
In nearly all the important wars of
modern times.
Nebraska City had held franchise
for twelve years for the construction of
a pontoon bridge. All movements in
the direction of carrying on the work
met with the inevitable objectia-
those Interested iniat }<6fnkpatsf
.%asls ." ~ EISl5 Y Stand.
iAI5HfEt X111& go - f1Ver carries
I&{tbF logs and trees,
III ~ &011eiW would seem to make the
{H3ainfenance of such a structure impos-
sible.
| The river at this point has two arms.
Over one of them permanent crib
work bridge passes, having a total
length of l ,050 feet. Where il stops the
pontoon bridge sbesins, and reaches
Y q 4, ,u.,
| 1,O74 teet AS will be seen from the
cut, the bridge is angular or V-shaped.
The point or apes Sthe.xnD4ies points -
down stream. When II is necessary TO
open the draw, the coDneoeSQns at the
apex are loOsened and the ciirrenf
once swings the two men111ra Apart
leaving an unobstrncted chanbef of ~
feet in width. In this feature it is
largest drawbridge in the wor1
When it is desired TO close II, the eur
OF the draw members are brou2
together, the current being made TO
do most of the work. The enura
operation can be managed by one man
This is in strong contrast to othcf
structures of the same character. Tho
draw in the Prairie du Chien structure s
alluded to above requires u powerful
engine to close it.
The bridge is divided into a ROADWAY
for vehicles and two side paths for
foot travellers. The roadway is -
sixteen feet wide. On one side is
three-foot sidewalk, and on the other
side one of five and one e-half feet in
width. This gives a total width of
twenty-four and One-half feet.
The floats are anchored by a very
perfect system, and one which, il is
believed, will stand every condition the
ictr 10 bal fn ho 10
When it was in process of building, the
! water was within two feet of high
water mark, and the river swept down
many logs aud trees of great size.
Numbers were carried by the current
under the boats without any bad
effects. For the spring floods ii is
proposed to greatly increase the
strength of the steel anchoring cables.
The bows of the boats are to be sheath
; ed with iron and the bottoms are to
receive an extra planking of oak 1t
is considered certain that the rapid
/. current will sweep all obstacles under
the boats. 1t is proposed TO remove
> the bridge when ice forms on the river.
The object of arranging the draw i'm
the peculiar shape shown was to faci-
itate closing. The government, in
granting the charter, has stipulated for
30 wide an opsaing that it seemed
! doubtful If pontoon could be closed
q at right angles to the axis of the stream.
Both the pontoon and crib bridges
were built within the short space of
twenty-eight days, at a cost Of about
$ $4,000. Col. s.. N. Stewart, of Phila-
g delphia, was the constructs 0S.1'c c1;roaoO
= The pontoon bridge has proved SO
J, successful that it has been proposed to
o form company tor the construction of
r pontoon bridges across the Missouri
J. river. Certainly, from considerations
It of cheapuess and practicability, they
Q would seem 10 leave little to be desired.
= The multiplication of bridges across
= The great rivers of the west is move
g ment in the direction of advanced CIV
8 ilization. The simple and cheap pom
toOn bridges, by their number, NAV be
II made to do better work in facilitating
Il Intercourse than wou)d be'effected by
u q smaller numbeF of more pre.entious
e structures. For some years their
: service maybe all that will be desired,
I and, as they prove inadequate, one
by one they can be replaced by more
Il Dprmanauf vv0rkR