The Pensacola journal. (Pensacola, Fla.) 1898-1985, 1921-09-05
NEW STEEL
MILTON
Santa Rosa Capital Preparing
For Great Crowds at Dedica-
ton of Structure.


ing and formal dedication OF the mag
nifcent steel bridge spanning the
Blackwater river at that place. a
bridge filling in a link of the Old
Spanish Trail, which replaces an old
and Anticipated ferry system.
On the eastern side of the Black
water river automobiles may pick up
a good paved road. On the west side
are blocks and blocks OF new paving.
In determining upon a bridge for
this crossing many engineering prob
lens were encountered and investi-
cations covering several months were
carried on to develop a structure to
meet all requirements Of navigation
and highway traffic.
In all highway bridges it is said to
be the plans Of builders to preserve
lines which harmonic with local con-
ditions, and structures which elimi-
nate overhead steel or concrete mem
bers are preferred. At the Blackwater
bridge crossing, according to the engi-
neers there is a depth of water of
forty feet, and it was necessary to
maintain the pier dimensions as sman
as possible, as this portion of the
bridge is said to represent a large part
Of the total cost of the structure.
AS the distance between extreme
high water and the roadway level was
limited, and as the pier dimensions
had to be limited, the engineers in
charge of the work found it necessary
to develop a design which would meet
the conditions peculiar to the cross
ing. and still keep within the amount
of money available for the work.
After making soundings and finding
the substrata conditions. the engineers
Of the state road department prepared
pprofiIes and plats, togethe- with
specifications describing the nature of
the work to be undertaken. This in
formation was then placed on file and
contractors and bridge companies from
all parts of the United States were in
vited to submit bids for the bridge
for this crossing, the bidders to pre-
sent their own plans, showing type of
bridge thew proposed to furnish. Bids
closed in July, 1920, with the result
that contract was awarded for build
ing the bridge which has just been
completed.
The foundations for the bridge con-
sists OF two mass concrete piers and
two abutments. The concrete piers
/ are GaEIlCA QOWn 10 Gay GlI1Sd NJ
feet below the bottom of the steel
work, and rest on timber piles APP
proximately IS feet long. The bottom
sections of the piers are II IL feet
in diameter and the top sections are
10 feet in diameter. The end abut-
ments extend down below the steel
work % feet and rest on timber piles
driven into sand and clay, the ap-
crl
being 80 feet The weight OF concrete
in piers is said to be about 100000
pounds.
The superstructure Of the bridge
consists of two Marlborough truss
steel spans each 100 feet center to
center of bearings, and one double leaf
plate deck plate girder bascule span
on the Scherzer rolling lift type with
span between bearing Of IS feet and
5 inches, the total length Of the bridge |
being exactly s2S feet. The bridge has
a roadway for highway traffic 1S feet
wide and one six-foot sidewalk. The
bridge, it was stated is designated to |
carry a load OF one 26-ton road roller I
OF so pounds per square foot over the
entire area of the roadway, making /
the structure, II is asserted, the heavi- |
est highway UA4ukG "a LIS SIG Al %AO 1
state OF Florida. The roadway con-
sists of 2x4, .creosoted tirnbers resting
on edge. toe-nailed into cresoted strips
supported on steel stringers.
The lift span is of double leaf can
tilever type designed to operate by
electric power, by one operator. with
in one minute. Until navigation on
the river becomes more frequent thei
bridge will be operated by hand power.
tests showing that one man can OPP
crate each leaf by hand power within
two minutes. so perfectly balanced are
the great lifts. One advantage in the
double leaf deck type of lift span is
the fact that when the leaves are in
the open position. both roadways are
completely blocked. making it impos-
sible for automobiles or other vehicles
to run into the river.
An interesting feature Of the build
ing Of this bridge was the method en-
ployed in erecting the fixed steel
spans. All steel was assembled at
the plant of the Pensacola Shipbuild
ing Company, builders of the bridge,
and the spans were erected complete
on barges in Bayou Chico and then
towed a distance Of 80 miles to the
bridge site at Milton. After arrival
at Milton about two hours were re-
quired to set the spans in place on
the foundations which had been pre-
pared The leaves of the lift span
were erected in the vertical position
to avoid interference with. navigation
in the river.
The foundations for the bridge were
designed and built by the state road
department, and plans for the SUPER
structure were furnished and the
structure fabricated and erected byI
the Pensacola Shipbuilding Company.
There has been quite a program pre-
pared for the occasion. With the arrival
OF scores Of automobiles early in the day,
the ceremonials win begin. Picnic grounds
at Bayou Marquis, across ON the main