Bismarck weekly tribune. [volume] (Bismarck, Dakota [N.D.]) 1884-1943, 1898-04-08
Moving The Pier.

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Moving The Pier.
The Cincinnati Enquirer has an inter-
esting article relative to the moving of
the east pier of the Missouri river bridge
at Bismarck. 1t says: The plans Of this
great undertaking were drawn by Mr..
S. j. Bratager, chief draughtsman, upon
the calculations and specifications of
Chief Engineer E. H. McIEenry and
Division Engineer w. L. Darling, of the
N. P. railway, and the work is now we'll
advanced under the personal direction
Of Mr.. Thomas j. Molloy, the we'll
known Cincinnati contractor.
The methods employed as is usual in
American practice are extremely simple,
yet every successive step from the re.
moval of the pressing earth to the lamp
ing of the last box full of concrete, calls
for unremitting caution and skill of the
highest order. The winter river is now
low and ice-bound, offering the best op,
portunity for the prosecution of the
ork which must be carried to a depth
of sixty feet below ground and thirty
feet below low water mark. The earth
on the land side of the pier has been re.
moved, and.a shaft sunk thirteen feet
below the old foundation. At a depth
of three and one-half feet a vein of coal
was struck, and it is on this the water
soaked earth has slipped, bearing the
pier along with it. Immediately under
the center of the pier a tunnel has been
dug, about five feet wide, thirteen feet
deep and thirty-two feet long; running
from the river face, under the pier, to a
distance of eight feet beyond the shore
face. This tunnel will be partially filled
with cement concrete, and or this a
framework of 8 by 8 timber will be con
structed, reaching up nearly to the bot
tom of the old pier, and supporting two
tracks, each consisting of four 56-pound
steel rails. On these tracks will be
placed two rows of steel rollers, two
inches in diameter and spaced one inch
apart. Resting on these rollers, and
touching the bottom of the pier above
will be eight more steel rails under
which one tenth of the weight will rest
during the moving.
The two tiers of rails, with the rollers
between, are securely fastened, wedged
up tight, and brought to an wen bear.
ing on the bottom of the pier, after
which the tunnel is packed with cement
concrete clear up to the lower rails
which are imbedded in it. On each
side of the rails only sufficient space il
left between the bottom of the old piel
and the top of the new concrete for
man to crawl in to adjust any rollers
which might need attention. A SECOND
tunnel is now dug at one side and til,
same operation followed-partial filling
up with concrete, erection of woodwork
laying and wedging up of rails aud rol
Iers, complete filling with concrete
Other tunnels follow in such an orde
as not to disturb the equilibrium of tn
pier during the slight settlement which
is bound to occur. In all, ten tunnel
will be driven, removing all the materia
below the old masonry and from tn
earth which formerly supported it
gradually shifting the weight Of the pie
to 40 steel rails, resting upon $50 stee
rollers, which in turn bear upon the II
rails of the lower tier imbedded in the
new concrete. This has now assumed
the form of a monolith, and bears the
entire weight of all above it, rails, roll
lers, pier and bridge. On the river side
this great block of artificial stone ii
flush with the face of the pier, but OF
the land side it extends like a shell
eight feet in width. To roll the piel
across this shelf to it's proper place viii
require a pull equal to nearly 1,5OO,OOt
pounds. which will be applied through
ten large screws, bolted to the lower
block of concrete and pulling on the
ends of the upper tier of rails. Six
levers OF heavy oak, lO1s feet long will
actuate each of the ten screws, ano
under their combined strains the oldpiel
will roll slowly across its new founda'
ton, while the ends of the two bridge
spans above will come into place on roll
lers adjusted under them. When the
pier is finally in place, after removing
all temporary appliances, the narrow
manholes left untitled between the new
work and the old are now rammed tight
with concrete, to the old pier and thu
new base become me-. The foundation
is now one foot longer, eight feet wider
and thirteen feet deeper than before
As much masonry and concrete will b.
added as may be deemed sufficient t.
prevent all danger of any future move
ment, and the pier will stand in it's ole
position as a silent witness to the skill
and economy of American engineering
and it's triumph over natural difficulties