Evening star., 1893-12-12
.AOUEDUCT BRIDGE.
How the Piers Were Built Under
Great Difficulties.
OF INTEREST JUST NOW.
Bearing on the Ability Of the Piers
to Garry a Railroad.
A FIGHT AGAINST ODDS.

A FIGHT AGAINST ODDS.
The aqueduct piers being now Of consid-
cradle interest to Georgetowners inasmuch
as they are striving to get the use Of them
for electric railroad companies desiring to
enter the town. the following msy lend ad-
ditional interest to them:
When 1t was decided by the Alexandria
Canal Company and others most interested
to construct an aqueduct, the work was
looked upon as such a gigantic one, particu-
larry when the proposed character Of the
piers was made known. that the project was
cried down on all sides.
The site for the proposed structure had
been already fixed in 1870 by the engineers
of The Chesapeake and Ohio company, but
Maj. Turnbull and Mr.. Fairfax Of the Alex
andria company, after a careful resurvey Of
the river, decided upon a shorter and more
advantageous line. Acting in accordance
with their plan. they applied to the mayor
of Georgetown for permission to rest the
northern abutment of the proposed struc-
ture on the lower end of Lingan street. No
action was taken at that time. however.
The original idea was to construct twelve
arches Of stone. supported by eleven piers
feet span and twenty-five feet rise. the sup
ports to be curves of eleven centers; three
abutting piers, every third one to be twen-
ty-one feet thick at the springing of the
arch, and the masonry Of the land abut-
H.ents to be twenty-one feet thick-A cause
way $50 feet in length was substituted for
three of the arches at the Virginia end.
The adoption of the causeway made
change In the arrangement of the piers,
a Ii 1zl -
consist OF eight piers 1O5 feet apart; two of
them TO be abutment piers twenty-one feet
thick and six of them piers of support to
be each twelve feet thick at high water
mark.
The Golfer Dam.
The bids received on the work ranged
from sS9UO to s25O,OOO. Among them was
one from Martineau & Stewart, one OF
whom. DR.. Martineau, afterward sent in a
proposition for the Golfer dams alone, pro-
posing to build them on a plan which he
extolled as original. economical and easily
carried out. The engineers examined the
plan, but were unsatisfied with it, claiming
that dam made would not be water
tight. 1t would be incapable of resisting
the heavy pressure Of water which would
be thrown against 1t.
The plan at first had many defects, but
was finally made practicable with the
sistance Of Maj. Turnbull and other engi-
neers of note. Martineau d Company were
obliged to abandon the contract. though, be-
fore success was met with.
The engineers determined to construct the
piers on solid rock II difficulties beset them
by the score. But little experience in found
ing upon rock had been enjoyed in this
country prior to 1890.
Committees Report.
That difficulties were met with is proven
by the following from the committees re-
port:
"At length the critical period arrived
when it appeared highly probable that an
other days work would have defeated the
whole enterprise. 1t was known that moth
ing but actual perception Of the conse-
quences would bring conviction, which all
reasoning (resisted by the strong desire to
reach the rock) had failed to produce. Sew
eral of the stoutest laborers were set to
work with a view to dig a pit to the rock,
which was not more than three or four
feet from the then surface. They had not
pierced the mud above one-half its thick
ness before a column of water. copious and
alarming. suddenly gushed up. This pro-
duced an immediate conviction OF the un-
justifiable hazard of any further attempt
to bare the rock, and the Fictitious founda-
ton being without further hesitation agreed
to was accordingly commenced
Mai. TurnbuIps Report.
In Maj. Turnbull's report of the pro-
3
ment he said: LAS no memoirs or drawings
of this work had been published, nor OF the
London bridge the deepest perhaps in Eu-
rope), the engineers were obliged to pro-
ceed with the greatest caution. They were
aware of the very exposed situation of the
work and impressed with the absolute ne
cessity of founding 1t directly upon the
rock. The difficulties and dangers of the
attempt, although they were foreseen, were
deemed subordinate to the great object of
stability and in this view they were prompt
ly sustained by the president and directors
of the company"
Pumping the Water.
After the dam was constructed pudding
clay was thrown in between the two rows
Of piles and was rammed to make the dam
tight. Then the steam engine was used for
pumping the water and removing the mud
Seventeen feet of water was discharged
by two pumps in forty-eight hours and thir-
ty-two minutes. After a large portion of
the mud was removed, a break would fire.
quently occur. One dam Is known to have
been filled more than ten times before the
rock beneath the river was reached.
Curious Scene.
1t was such an unusual spectacle to see
men busily at work far below the surface
of the river. that people from all over the
District would visit the scene at every op-
portunity and linger there until necessity
called them away. Once, 1t Is recorded, the
President and his entire cabinet paid visit
to the works and were exceedingly interest
ed. Though the engineer had confidence in
the ultimate consummation Of his scheme,
the uncertain ability of the dam to resist
the immense pressure which was constantly
against Ii naturally caused him much
anxiety.
But wherever there Ii brain, untiring
energy and money something Is surely to be
accomplished, and at last after several years
had been spent in unceasing and conscien-
tious work Major Turnbull had the pleasure
of seeing eight of the most solid piers that
had ever been erected towering twenty nine
feet above high water mark At the head
of each Of these bridge supports was con-
structed an ice breaker Of cut granite, the
two lower courses being five feet below high
water mark and twenty-five inches thick.
No stone used was in size less than twenty
cubic feet. When all the piers had been
constructed a steam engine removed the
dams by driving upward Of fifty piles a
day.
COngratulates Himself.
When" said the major afterward. II re-
fleet upon the numerous difficulties which
We have oyercoma in the prORreas the