Evening star., 1902-08-02
NEW: HIGHWAY BRIDGE
Site felscted by Engineers
q Approved.
PLANS 70 BE PREPARED
COL. ALLEN TO BEGIN PRELIMIN-
AIRY WORK AT ONCE.
Recommendations of the Army Board
Favorably Considered by the
Acting Secretary of War.


important action was taken at the war
department today toward the construction
| OF the highway bridge across the Potomac
| as a partial substitute OF the old Long
| bridge. AT the recent session of Congress
the sum Of $4,000 was appropriated for
tne proposed structure and four years were
allowed for dts construction. The original
authority for the bridge was contained in
| the act approved February 12. 1901, pro-
Viding for the elimination Of certain grade
| crossings on the line Of the Baltimore and
Potomac Railroad Company in this city.
In pursuance of that act a board Of en-
! gineer officers, Of which Colonel Charles
j. Allen was president. was constituted
| by the Secretary of War to select a site
and formulate plans, specifications and es-
| Inmates for the bridge. The cost of the
| bridge was limited by the act to $56S,oOO.
Alter careful consideration the board
selected site paraleiing the railroad
| bridge now under construction and about
1,OO feet further up the river, and pre-
pared and recommended plans and specif-
| cations for bridge estimated to cost $685.
OOo The board reported that this was the
| least amount for which satisfactory
bridge could be built. AS the amount was
greatly In excess of the available appro-
priation. the Secretary of War decided to
defer action until Congress could again con-
! slider. the matter
| The wisdom Of this action was demon
| strated by the action of Congress in June
| last In increasing the appropriation for the
bridge to s996,O0O and increasing the time
| limit for its construction from two to four
| years. This legislation was also a practi-
cal adOnfjn0 of ha sinh cd NV
| the engineer board, and consequently the
general features of that design will be fol-
| lowed in the construction of the bridge in
Guiding the location.
Recommendations Approved.
Gen. Gillespie, chief of engineers, and Col.
| Mackenzie. his principal assistant, who
| have given the matter considerable atten-
| ton. recommended to the Secretary Of
| War a few days ago that the site selected
| by the board be approved and that the
| plans anb Specifications be prepared in ac-
| cordance with the approved design. They
| also rec6fnmelfded that the preparation Of
specifications, 1letc.. for the construction
of the bridgeose placed in charge Of Col.
Charles ], Alien, corps Of Engineers, and
with a vfaaw ta entering into a contract or
| contracts for ehe prosecution Of the work.
These recommendations have been APPROX
| ed by Assistant Secretary Sanger. acting
l,,ol
| notified 70 begin the preliminary work
! notified 30 b.1gin the preliminary work
! without I4felayt. '.a5.
" The New Bridge.
The ptpposed' bridge is to consist prin-
| cipally of II fixed spans Of PIC feet each,
or 211 feet inches between centers Of
end pirfs. ana 1 revolving (horizontaD
drawspah OF '2M feet, to afford clear open
| ing Of 100 feer on each side Of the pivot
| pierNtlte superstructure to be of steel and
I to restaupon stone piers.
| The structure, is provided with double
track for the passage Of electric cars; the
| total width of roadway, for cars and ve-
hicles being 10 feet between wheel guards,
and the sidewalks, one on each side of
the bridge, feet wide in the clear, the
| total width OF superstructure from out to
| out Of sidewalk railing being about g.
| feet. The sidewalks are of granolithic
| pavement and the roadway of sheet
| asphalt, supported on buckle plates. The
draw is operated by means Of electric
motors. The cars will be operated by cleo
trio power through trolley, overhead on the
| bridge proper and the approaches on
| the Virginia side and sunken on the park
| approaches on the Washington side of the
Potomac. ~.
| The most pleasing form of through truss,
| according to the board, Is one with curv-
| ed top chord. The bowstrine which affords
! the maximum OF curvature was considered
difficult to brace against wind stresses
which at this locality will be severe The
Pratt truss with curved top chord. which
| Is described as the most economical truss
which can be used for spans Of the length
| here proposed, and furnishing a somewhat
| pleasing appearance, has been adopted for
| the bridge.
Across Potomac Park.
| The approaches across Potomac Park Will
| be OF earth embankment with moderate
| slopes. excepting that portion of the tidal
reservoir In Potomac Park will be crossed
| by a steel-plate girder. which may receive
more or less ornamentation. A clear sLace
| Of 100 feet is to be left between the SOUTH
| erly end of the enbankment and the sea
| wall of Potomac Park for walks and drive
ways. This 1oO-foot space at the sea wall
| Is regarded by the board as ample
! The board says: The earth slopes of the
| approaches. along the crossing of Potomac
| Park, can be eventually sodded, spaces be
ing left for trees. flower beds, shrubs etc
similar to those in some of the parks of
Washington and other cities affordng a
pleasing and economical ornamentation. The
crossing Of the park by the highway in
fringes upon the park area and drives hut
it seems to be unavoidable. and the adjust
ment of the relation Of bridge approach to
park drives. and areas can only be harmon
ized when detailed and final plans for both
are drawn.
The piers and abutments Of the bridge
| will rest on foundations of deeply driven
piles, the bOringS and pile tests giving con-
fdence that such foundations will suffice
and be economical
The Cost.
The total eost Of the approved design is
estimated at .$9S6,0o0. as follows:
Washington approach to plate-girder
bridge. ,2oo; piate-eirder bridge complete,
s6l,Oo0: causesray, $4,000: approach to
bridge fr8Sh Washington side SIG. 800: abut-
ment on ~ asfnRgton side, $123OO; six piers,
at $1s. 5000 $fafSOO four PIERS at So, 500.
sol 900; bffot'itfer $4,000: pile protection
for swing span. and guide sheers, s11 800;
one pier SCI. 500; southwest abutment. s2s,.
400; elevsh. fxfsa s spans. at $500. s427 900;
one swing span. with supporting girders
and operating machinery. 81. 400: Southwest
approachss inelgading =. temporary roadway to
Alexandrfs tnEfpike and land damages.
$34. .1sO; tSnttnSencies, per cent, $3s 800; Z.
total, s9gSDo0. ~,
The above ihcludes asphalt roadway,
granolithir si1ewalks curbs, railing and
lamps fr8m Mstyland avenue to the South ihe
west ab3tmentU Of I'll the bridge and for the
olithic Sidewalks. curb, railing and lamps
for distance ct 500 feet from the south