The daily morning journal and courier. [volume] (New Haven, Conn.) 1894-1907, 1901-05-27
STEEL BRIDGES BY THE POUND

The Price Per Pound is Small, Blu
Some Bridges Weigh a Good Man!
Pounds.
Steel railway bridges Weighing per
haps 10000 tons apiece, and sold +. 0. b
in Chicago at 81 to 81 cents pound
are one of the anomalies of business
But 1t is by the pound, delivered II
Chicago, that the Burlington road sys-
TEN buys all it's bridges and pays fol
most of the repairs to old bridges in the
same way. This work is all let by con-
tract and bids for it made by the pound
The price varies according to the mar.
ket prices on steel Three years age
bridges were bought as low as 1855 cents
pound but the range to-day is 81 to
3% cents pound. On this railway sys-
tenn, for all bridges not exceeding 1Os
feet in length, the girder pattern is
used, with the framework riveted to-
gether. Above this length the truss
pattern is required, having steel plates
drilled at the ends for coupling with
other plates by steel pins.
! Assistant Engineer It. Jordan of the
Burlington system was asked as to rail
way bridge building in general. In
the experience Of the modern railroad"
he said, few bridges have had to be
replaced in the last quarter of a CEN
fury because they have worn out. The
increased demands of traffic have made
them out of date, either because they
were not wide enough for double-track-
ing or because they were not built for
such loads as we are now putting in
cars. In building bridges the weight
and speed of trains must be taken into
consideration so as to avoid slowing
down as much as possible. Take the
ordinary bridge without draw in 1t
for the passage of boats; no train is
expected to slow down because of it,
because that section of track is suppos-
ed to be as firm as any other
Few people realize how carefully
bridges must be constructed In ordrr
to stand. Tn the margin between the
extremes Of heat and cold in this eli
mate steel bridge will expand and
contract IL of it's length, and to allow
for this one end Of a bridge Is hung
from giant link that swings to allow
for expansion at one pier In the
trusses of the truss bridges the steel
sections pinned together must be with
in ga Of an inch in length between the
drilled holes for the pins. To accom-
plish this each section of steel must be
at exactly the same temperature as the
others at the time of drilling. The
drills which cut them are fixed to a
steel shaft which expands or contracts
according to the atmosphere of the
shop in which the bridge steels are
kept for drilling. These pieces are
clamped together tightly and bored ac-
cording to pattern, insuring that each
piece will be just the same length of the
others whenever they are of the same
temperature.
"As to iron or steel bridges under
strain of traffic one of the theories Of
these metals Is that constant strain
and jarring tend to me.ke them tired
This is a weakening process brought
about by the crystallizing of the MOLE
cules, making bar much more likely
to snap. In 1894 one Of this company's
bridges wos still standing over the Mis-
slssippi river at Burlington, Ia, where
1t had stood since 1868. 1t was an iron
bridge, as steel bridges were unknown
at the time of the building of it.
1.-THE company decided to take out
one span of this structure in order to
test the condition of the bridge irons.
1t was a costly bit of experimenting,
as it proved that the iron
was as good as 1t was when it was put
into the structure twenty-six years be-
fore, 1t was in such good condition
that the last piece of it was put back
and stayed there until it was found
to take the bridge down to
make way for double tracks. On this
bridge all trains had been run slowly,
not because of the bridge, but because