Evening star. [volume] (Washington, D.C.) 1854-1972, 1908-10-14
HOPES OF NEW YORK DIVER FINDS DEFECT
Encouraging Views Given to Reports Aqueduct Bridge Piers
the President. Are 0eteroratng:
GEN. BURNETT SANGUfNE I'm THE FORM OF CAVITIES
Declares That Both Taft Hughes Cosby Tells
Will Carry State Repairs.
EFFORTS TO GET VIRGINIA RESULTS OF EXAMINATION
Prominent Republicans Will Speak
in the Old Dominion fords Crossing
in Massachusetts, Georgetown.
IN THE FORM OF CAVITIES
Maj. Cosby Tells Of Erosion Since the
Last Repairs.
RESULTS OF EXAMINATION
History Of the Structure That AZ.
fords Means Of Crossing Poto.
mac at Georgetown.

mac at Georgetown.
Recent examinations by divers show
that there is In process q gradual de-
terioration Of the piers Of the AQueduct
bridge crossing the Potomac river at
Georgetown. A statement to that effect
is contained in q report just received BY
Gen. Marshall. chief Of engineers. from
Maj. Cosby. the officer in charge OF river
improvements. According to the report,
the defects in the piers show usually in
the form Of cavities caused by the drop
ping out OF stones In or near the face
during freshets. These cavities hovp'
been repaired by filling them with con-
crete In bags and in some instances the
repaired portions have been protected by
placing riprap In front OF them. In the
case of three of the piers. Nos. 1. 4 and
0. the defects were % serious that that
method OF repairs was impracticable. and
1t became necessary to build entirely new
piers.
Maj Cosby says that considerable ero-
sion has occurred in some of the piers
since repairs were last made in the
spring Of 1907. and that all the old
piers. except No. 2. required additional
ASpoAC' 4hC C6StyJSB, Wnlle IeWeT In
number. ne says. were somewhat iarKer
than are usually found. They were fiied
In the usual manner with concrete mixed
on a scow. placed in burlap bags Of
s1table sizes and lowered to the diver.
who built them into the masonry. Dur
Ing the past month about 20.5 cubic yards
OF concrete were placed in that way at q
total cost for material. labor and sup
plies Of $S78. Ia. or about $3.50 per cubic
yard.
Results Of the Examinations.
Going into details CT the results OF the
examinations just completed MAI Cosby
says that a large cavity was found In
pier No. 8. which is the third from the
Virginia shore. 1t was at the down-stream
end. and extended from about The center
Of the end around to the south sjde for
q distance 81 about eight feet The top
e The esvity wgs e6cyt Nen&y feet below
ess,, ene ws.sf ssss HnS and thS bottom sbout
rock hea5ss-the river. f3s bottom three
feet and the back Of the cavity we're fIied
with mud and clay. The cavity dpparent-
fycr y rups e., n;sk shout etEht fea Foln the
remove the mud for more than three feet
In The rock was cleaned on and q vail
OF concrete in bags built up against the
moa. MAJ; Cosby says that evidence OF q
slight settlement at this end OF the pier
can be traced in the joints between the
water line and the coping.
In pier No. q cavity was found at
the down-stream end near the bottom
line. 1t extended from about the center
OF the END FOR distance OF about twelve
Ieet around the end and along the north
sioe. 1t Is about three feet high at tho
race and extends into the pier about fiye
feet The cavity was filled with soft mud.
which was cleaned out and the hoIe
.ncn S nIleo with bags OF concrete. In pier
NO. were found greater number OF de-
piers. but the individual cavities were not
50 !arge as those found in piers No. 8 and
T. Iney ranged from a few cubic feet TO
about one and half cubic yards.
Built About 1835-ls40.
The piers Of the Aqueduct bridge were
ouiit about 1S35-lS40. and were designed
10 carry the Chesapeake and Ohio canal
across the Potomac river at Georgetown.
Tney are composed of Potomac river
gneiss. excepting the icebreakers. which
are OF granite. Between the main river
aoutments there are eight piers, mum.
oered from the Virginia shore. about IIo
Ieet apart between faces at the top.
Every third pier Is about sixteen feet
wide at the top: the remaining piers
nave top widths Of about seven feet six
inches. The top Of each pier is about
tnirty feet above the plane of mean low
ferdams. and were supposed to have
been constructed of substantial masonry
founded directly upon the rock bed OF the
river.
There appears to have been many din.
culties attending the construction. Ac-
c0rding to the original plan the super
structure was to have consisted of nine
stone arches. the two broader piers to
serve as sectional abutments. For eco
nomical. reasons. however. a wooden
truss bridge and trough Of kyanised tim
ber were substituted. This structure was
the Potomac aQueduct."
In 1865 the Alexandria Canal Com.
pany leased it's canal and the Aqueduct
bridge to Messrs. Quigley. Wells and
Dugan for a period OF ninety-ninc
years. The lessees replaced the old
unsafe. by Howe truss. and the latter
was subsequently strengthened by
wooden arches. By act Of Congress
approved July q. 1868. the lessees were
authorized to erect and maintain. in
connection with the aQueduct, a high
way bridge and to charge certain spec
flied rates of toll. A floor system was
placed on the top chord OF the Howe
truss. trestles and spans Of the an
proaches were built and the bridge used
as highway until 1896 For several
years prior to the date named how
ever. the condition Of the bridge was
not deemed satisfactory. and examna-
tions made by army engineers resulted
safe for public travel.
Government Acquires Ownership.
An act OF Congress approved June
q. 1886. provided for the establish
ment OF a free bridge. either by the pur-
chase of the Aqueduct bridge piers ana
the erection Of an iron bridge thereon
or by the construction OF new bridge at
or near the Three Sisters about one-haif
mile above the Aqueduct.' Under the
provision OF that act, the bridge was
purchased by the United States govern
ment. The existing iron superstruc-
ture was constructed by the army Ea-
neer Corps. being completed In IssS
Attention appears to have been first
called to the defective construction OF
the piers Immediately after the freshet
of 1854 and extensive repairs We're
made to six Of them by means OF
cement concrete In hags placed by
a diver Pier No. 4 was so badly eroded
that IL became necessary to replace It
with an entirely new pier. Subsequently
piers Nos and were also entirely
reconstructed.
nv Col C. E. L. b. Davis. Corps OF En-
gineers In 1895 Il was stated that the
timber cross braces Of the old original
cofferdam built In 1890. sixteen inches
square and twenty-one in number, had
been left In pier No. and the masonry