The evening times., 1900-05-18
THE MEMORIAL BRIDGE
Secretary Root Sends to Congress
a Report on the Designs.
The Offering Of WiIIiaia II. Barr, He
Says, Meets All the Requirements
and should BE AdOpted-The Cost
to BE Sf,S6o, ,ooO-A Descrip-
tion of the Proposed Structure.

SLaleS lnaJ tne design CI William H. burr.
as first in the order of merit, meets all
conditions required ard should be adopted
The estimated cost of Mr.. Burr's design Is
given at s4.S60. coo. Secretary Root states
in a letter accompanying the report that
be eoncurs in the decision of the board
and recommends that the Burr design be
adopted by Congress.
The report states that there were sub
/ mitted for the consideration OF the Board
two designs each by Messrs. l. l. Buck.
William r Hutton. and George s. Mori-
son. and three designs by Mr. William II.
Burr. After careful study the Board
places the comparative merits Of the de-
signs as follows;
NO. l. Design No. of Mr. william H
Burr.
NO. 2. Design No. 2 of Mr.. William r
Hutton.
No 3 Design No. I OF Mr. l. L Buck
NO. l. Design No 1 of Mr. George S.
Morrison
The board expresses the opinion that
the general design of Mr. Burr. desig-
mated as the first in the order OF merit,
meets the conditions Of the problem and
should be adopted, subject to certain rec
concentrations and notifications set forth
in the report, To width. slope Of road
way, curve Of under side OF draw towers.
provision for tramcars, elevation OF initial
point, etc, and such other minor mOdifca-
tions as experience may suggest upon the
undertaking OF the work or during its
progress"
After a history OF the attempts made in
! the past to obtain a great bridge 70 span
the space between the Naval Observatory
and Arlington. the report tells OF the ef-
forts 70 organize the board and to get
the best bridge architects 10 compete.
The accepted design is described as FOL
lows The best features Of Mr.. Burrs
three designs are TO be combined in the
structure:
This IS a design for a double-deek
/ bridge co feet in width between railings.
Two sidewalks, each ten feet wide. and d
roadway forty feet wide are carried upon
[ the upper deck, while a double-track street
railway is provided for upon the lower
/ deck. The total length Of the open work
Of the bridge proper ard approaches is
about g. 40 feet
The bridge proper consists Of two 2S3-
foot span steel arches. one steel draw span
having clear span OF 2I3 feet, and two
more 2S3-fOOt steel arches
The 2S3-fOot steel arches are circular
| (segmental, the sprilging line being
"a feet above mean it7 water. the rise IS
/ feet above the sprink md the radius OF
the intrados about 400 feet. The clear
headroom under the crown CT the arches is
80 feet 4 clear headTOon Of about IS feet
9 inches is provided under these arches for
a width OF 80 feet at the centre and about
60 feet inches for width Of 100 feet.
There are FIVE 2-hinged, solid web steel
arch ribs. 10 feet in depth. with spandrels
OF open steel construction IN each span
These ribs and spandrel posts carry the
floor beams and stringers, which in turn
support the buckle plate foundation for the
asphalt roadway and graDoIithic sidewalk
Of the upper deck and the ties Of the street
railroad OF the lawer deck
The drawspan is composed OF > bascule
arms supported on trunnions. balanced by
rear extensions and counterweights The
clear opening is about 167 feet the clear
span at low-water level 213 feet. and the
span from centre TO centre of trunnions
225 feet II 1-2 inches. The bsscule arms
are composed OF steel ribs or trusses. OF
the lattice girder type. with parallel chords,
Is feet deep over all. The clear headroom
is about so feet when the draw is closed
The floor is 20 be Of asphalt cork blocks
molded 10 fl the buckle plates which are
supported as above, or alternatively Of pre-
pared wood II is proposed TO operate the
draw By four 50-horsepower electric mo-
tors.
The Washington approach consists Of
IS 46-foot masonry arches, back Of which
is an earthen enbankment about 500 feet
| long.
The 46-foot span masonry arches are
| full semi-circular. the springing line being
"A feet above low water. the rise above
! tie spring % feet, and the radius or the
| intradOs % feet. The face Of the arch
ring is OF granite. but the main part Of
the ring is constructed on the Melan sys-
| ten Of combined concrete and steel. there
being main concrete steel ribs. The
granite arch ring is feeJ deep through
out. while the concrete and steel ribs are
20 IL inches deep al the crown and 10
inches deep at the spTing.-A masonry
| spaniel wall. partly o. granite and part
! ly Of concrete. provided with circular
I openings 10 admit light and air TO the
| lower deck rests upon the granite arch
rings. The asphalt roadway and grano-
I lithie sidewalks are supported by concrete
| hoOr arches between l-bsams- The weight
Of this floor system, together with that for
the street railway on the lower deck is
carried down to the ch ring by framed
| steel posts between the above masonry
| spandrel walls.
The Arlington approach consists Of p
46-foot masonry arches. identical with
those composing the Washington approach.
| back of which is about 1,500 linear feet
of earth embankment.
The two bascule piers and the adjacent
I piers between the 2S3-foot steel spans are
| tc be built on bed rock by the pnenmatic
process, the caissons 20 be filed with con-
crete. The other piers are also to be found
| Cd upon bed rock and built up within eof-
| fe, dams The facing Of all piers is to Be
granite and the interior concrete. The
shore piers of the river spsns and all the
/ piers OF the approaches and Of the abut-
ments are pierced with arches whose axes
/ are parallel TO the axis of the structure
| These arches have spans of "a or IS feet.
and their springing lines are at the eleva-
| tion Of low water They are inserted for
purposes OF economy. The oombinati-n OF
| steel with concrete Is used in tne rie-s as
well as in the arches.
The grades OF the upper roadway ere as
| follows: Beginning with an elevation OF
| about f0rty-five feet at the intersection OF
| Twenty-third Street ard New York Ave
nue., there is a rising grade OF per cent TO
| the first arch. from which point the grade
| is level at an elevation OF sixty-five feet 10
/ the end of the open work on the Airing
| ton side, whence IL falls, upon a sight
grade. to the Georgetown and Alexandria
road The maximum grade proposed is
4 per cent.
THE principal divisions Of the bridge
! are marked by massive masonry arches
J and towers decorated with emblematic
\ groups Of statuary, etc Upon each Of the
bascule piers is erected a single arch.
| transverse with the roadway, constituting
1
| Newest ideGs abort House BuiIdiaG
| IN frame buildings always call first on + Lib