Evening star., 1952-09-01
SHEPHERDS LANDING
BRIDGE.

AS previously set forth in the
traffic report, a four-lane bridge
is required at the Shepherds
Landing location to cross the
Potomac to Alexandria. This
bridge is a deck girder structure
with swing span located over
the navigation channel near the
center Of the bridge. The design
is based on two 26-foot roadways
separated by a 4-foot median
strip, with two 6-foot sidewalks,
Span lengths are the most eco
nomical consistent with existing
foundation conditions.
/ The location and clearances
shown for the swing span have
been discussed informally with
the Corps of Engineers and are
believed to satisfy the require
ments for navigation. The swing
span provides for 150-foot clear
horizontal distance on each side
of the pivot pier, and for a verti-
cal clearance Of so feet above
mean low water. This vertical
clearance will allow the passage
Of all but relatively few Of the
vessels regularly using the Po-
tomac River to and from WASH
ington without opening the swing
span.
The overall height of the bridge
lis considerably under the maxi
mum acceptable height of ITO feet
above mean low water permitted
by the Civil Aeronautics Admins
Itration to avoid interference with
air traffic at the Washington Ma
tional Airport.
Information relating to founda-
tion conditions was obtained from
logs Of borings taken at the nearby
site of the emergency railroad
bridge in use during the recent
war, and since removed. Piers
supported on piles driven into the
hard clay, sand and gravel under
lying the mud and silt encountered
on the river bottom were found
to be most economical and foun-
dations of this type have been
used. The pivot pier of the swing
span is supported on a caisson
founded at approximately 100 feet
below mean low water in hard
clay, sand and gravel.
The District approach to the
Shepherds Landing Bridge con-
meets to the proposed Anacostia-
Kenilworth freeway at Overlook
avenue and Chesapeake street anc
provides for future connection tt
the proposed George Washington
Memorial parkway and to the pro.
posed Washington bypass. The
Alexandria approach connects tc
the Mount Vernon Memorial high.
way and to U. s. Route ! at Henry
street and extends through Alex.
andria to a connection with thS
Shirley Memorial highway. Ths
route through Alexandria wa.
chosen as being the most eco
nomical and least destructive o.
property after q thorough study
of the area. Consideration wa
given to the use of Duke stree
as part of the route but the diff
ficulty of providing a controlle'
access highway of the requires
, width. and the high property dam
ages involved makes the use o
this street impractical. Any rout
Through Alexandria, including tn
one selected, necessarily involve
!. numerous street changes and til
I acquisition Of property now &C
cupled by dwellings and bushes
establishments. Provision Is mad
for access in both directions to tn
proposed route in the vicinity Q
King street. Beyond Alexandri
the route is extended as a con
trolled access highway to Shirle
Z Memorial highway, with an inter
change at Telegraph road.
Construction Cost.
The estimated construction COS
! which follows includes the cost
! grading and paving roadway. con
8 struction Of the main bridg,
2 grade separation structures an
! Iinterchanges. Connections to tn
Ylproposed George Washingto
4IMemorial Parkway and to the ~