The daily union. [volume] (Washington [D.C.]) 1845-1857, 1857-02-12

them The bolerpate grder has been adopted as being
highly suitable for the purpose according with the arch
lecture Of the bridge easily protected against oxidation
and on that account Of great durability.
The draw will be thirtyfour feet wide sufficient for
singe-uack railroad common road, and side walks The
cost OF the whole structure including three arches the
Virginia channel and modification of causeway adapt
1t to the level amounts according estimates here
with submitted 10 So 000 without railroad facilities
to ~ 000 with solid inclined causeway suspension
arch TO S26ooo0o; without railroad facilities 81 $780,
present neither plans estimates of suspension
bridge for the locality under consideration
which, hope will be deemed fully sufficient TO Justify the
omission. The low banks of the river this point pre-
cude the possibility of erecting rational structure
sufficient elevation to allow of the free passage of shipping
Admitting draw due regard TO the interests of naviga
ton would still necesstate the erection of supporting piers
one hundred and twenty feet above low water and
points one hundred and eighty feet above solid ground
The erection OF these piers would require very heavy ex
peuditures owing to their dimensions and the
difficulties presented by their foundations. series of
arches for suspension bridge an unavorabe feature in
any event. and becomes still more should the passage of
railway be thought advisable A bar-ron suspension
bridge expensive and its duration uncertain as its safety
depends the less faithful execution OF vast
number of wells Nor wire suspension bridge be
thought durable as, when made equally
strong IL presents to the destructive action of oxidation
surface forty times great Let not be supposed how
ever, to condemn suspension bridges under all crcum-
stances structure that may boldly and very appropr
atey span Niagara the Ohio at Wheeling may yet be
wholly unsulted to the Potomac at w Washington.
An elevation Of casron arch bridge accompanies this
report Such structure would be handsome and durable
although its expense would be but little inferior that of
the stonearch bridge which greatly superior in durab
ity and beauty.
1t has occurred TO that boilerplate Orders resting
ON pneumatic cast-iron cylinders woald form substan
fractions in architectural point of view. An additional
cylinder terminating in incline plane would probably
form an eectua protection against the ice The estimated
cost OF such a bridge would be about 100000.
Considered solely in engineering and unitarian point
OF view the most rational construction perhaps that could
be placed at the site of the Long Bridge would be solid
stone piers, and light wroughron spans of 200 to $50
feet was not authorized to PRESENT such design,
would the limited time my disposal have admitted of it,
Should plan of this kind be desired it could be easily
presented to Congress its next session Its conctura
$95O,OOo. .eEH
With regard to railroad connection the Long Bridge site
presents every desirable facility. connexon with the
Baltimore and Washington depot was thoroughly
ned and most favorable results obtained The proposed
route would be from the bridge along to
south street thence direct to within short distance of
the canal at which point of 1000 feet
radius leading to tunnel entrance at south street
tunnel 200 feet long terminates the line This tunnel would
be of execution requiring to be simply
ted brcked and recovered 1t would lie for great
portion Of way under the Capitol grounds but at
amply sufficient depth to avoid any interference with their
disposition and arrangements This line would present
grades of fifty feet to the mile; would give sut
GENTLY curves and would affect the city but slightly
four streets amongst them the hghymporant Of
Pennsylvania avenue more properly the street that
forms its continuation pass over the tunnel and conse
quently experiences interruption. map and profile
Of the proposed route this report giving every
desirable Information.
| EAsBY's WHARF
The locality above the Long Bridge presenting ap
parent facilities for the construction of bridge is from
Easby wharf to the Virginia shore passing the south
portion of Mason island 1t has been suggested that
suspension bridge there could be constructed not
interfere with navigation. The location has been thor
oughy examined with reference to this object but without
favorable results The roadway would be 80 or 40 feet
above the highest available ground the Washington
shore feature Objectionable every way and precudng
the passage of railroad At such elevation the bridge
would be 1000 feet in length at best temporary sruc
ture and of immense expense.
A bridge at lower elevation could be built but it
cessary presents the disadvantage of draw and in that
respect similarly crcumstanced to the Long Bridge 1t
would cause the obstruction to navigation and not
accommodate large number of the citizens of Washing
ton Its cost would not be greatly inferior to that of any
similar structure at the site of the Long Bridge would
its foundations present much less difficulty "A few test
bongs indicate depth of from 80 to 35 feet to solid
to reach which the Golfer dam or diving bell becomes
| Indispensable.
The railroad connection, (see accompanying map al
though possible is not favorable the at the Long
Bridge. s
A Short distance above Easby's wharf occurs very
great contraction in the width OF the river 1t has been
erect bridge there, at moderate cost 1t would how
ever be dangerous to contract still further waterway
already insufficient by introducing persa necessity not
to be obvated by suspension bridge as draw would be
| again indispensable. .....a BAIRD. a.r. s.a ~
bridge at this point would greatly interfere with the
business and commerce of Georgetown, and present
facilities whatever for the passage of a railroad
| AQUEDUCT PIERS
Next in order the aqueduct PIERS which present
positive advantages for the construction of bridge A
draw is not needed while the piers already completed
These piers constructed by Major Turnbu in most
thorough and substantial manner and intended to
support stone arches.
herewith present complete and detailed drawings Of
bridge for spanning the aqueduct PIERS and aecommoda
ting canal railway, and common road together with
sdewalksa three important practical interests Nine
sone arches of los feet inches span will support the
aqueduct Pillars of masonry, resting partly the pier
head and partly the coping support supersructure Of
plate grders eight feet Deep spanning the distance
from pier to pier and bringing the level of the roadway
thrtytwo feet above the aqueduc seventytwo feet
above the river There twelve of these spans draw
ing admitting the entiancefree passage and exit of the
canal underneath This superstrucure is calculated to
six times the greatest passing load that
upon TIA limit fixed in England by the highest au
| thority.
The boilerpae grder has been adopted as being very
reliable presenting great durability, and in keeping with
the massive architecture of heavy stone bridge. At
point do the road and railroad interfere with each
oherhe former passing under the latter on either shore
while the bridge partition efectualy separates the
The bridge of Bercy, of the most requented of
the French capital presents striking example of the sue
cess attending this arrangement
Estimated cost of this bridge. $s32T68 90
Add 20 per cent for contingencies. l66b54 90
999322 90
il ia not doubted that several railroad companies would
be willing give large for the right of way, thus
greatly diminishing the necessary expenditures on the part
of the government
Thu countrv has been surveyed with refer