The Port Gibson reveille., 1916-10-05
CONCRETE BRIDGES.
Interesting Letter on Concrete VS..
Iron Bridges.
Concluded From Last Week.

1913, there is given a photograph
of the Washington Street Bridge
IN Dayton which was subjected to
the heaviest part of the flood, and
after the water subsided the bridge
was intact.
We cannot find any reference to
the late freshets 10 the Carolinas,
Georgia aud Alabama, but WI
refer our people to the test which
concrete structures were given in
Erie flood which occurred August
8, 1915. In this case there was
:loudburst and it raised the level
of Mill creek so high that it over
flowed most of the bridges and
;ulverts, and concrate stood up
emarkably well.
On September 2, 1912, there
was cloudburst in West Virginia.
rhe town of Golfers was almost
wiped out-2o persons were
drowned and it destroyed houses,
barns, sheds, and finally railroad
embankments. The terrific force
of the water may be realized by
the fact that two stationary loco
motive boilers, which stood just
west of the concrete bridge, were
moved over so feet and overturned.
Houses were torn from their foun.
dations, carried distance of over
200 yards and then torn to pieces
and placed upon the railroad en-,
bankment. The crest of the flood
passed a feet over the spandrel
walls, and a concrete highway
bridge of a 90 loot span, which was
completed on August 3 of that
year, a month bad hardly elapsed
between the completion of the
bridge and the food, suffered only
the breaking off of the guard rails
and the spalling of the sharp edge
of the up stream and OF the arch
barrel. This same storm carried
away d steel railroad bridges, II
highway bridges, and several minor
ones, and therefore we feel that
these examples are excellent ones
as regards the stability of concrete
when subject to food action.
There is still another feature of
the selection of the type of bridge
which is of extreme importance
relative to comparative COST
whether or not materials can be
supplied through or by local deal
ers, and whether the labor can to
a large extent be furnished by men
of the community. This feature
has not been used in the prepara
tion Of tbe comparative cost in the
preceding paragraph, but it is
nevertheless of prime importance
that money for any public i'm
provement should as far as posi-
BILE be spent in the community
making the Improvement. In the
case of a steel bridge, the skilled
labor comes from another locality
and the steel is fabricated in dis
tant mills. The material for
concrete bridge, the cement, sand,
stone, small rolled steel rods, lum-
Der, teams and help usually come
from local sources.
There are many features which
we could enumerate in this com
on concrete bridges,
particularly small concrete slab
and arch bridges.
The Pennsylvania railroad, the
best equipped railway in America.
is replacing all stone, wood and
steel bridges with concrete ones.
And it is only a question of time
when Federal, State, County and
Municipality will adopt concrete
bridges and recognize that we are
in the cement age.
We have number of photo
graphs which will show The stabil
ity of concrete bridges when SUBJ
iect to flood actions.
We fee amply repaid for this
discussion if concrete bridges be-
come the fixed policy OF the county
fathers in the future, though advo-
:ated by a coruheld engineer.
JAMES F. MccALEB, MD. |,