Evening star. [volume] (Washington, D.C.) 1854-1972, 1909-08-04
Serves Double Purpose.

The new structure not only provides
highway across the narrow inlet. but also
provides means for controlling the flow
of water in and out of the tidal basin.
That result is obtained by the introduce
ton of curtains and automatic gates,
the mechanism for operating which is
located on platform below the surface
of the bridge. Under the central span
is a lock large enough to allow boats of
not more than twelve feet beam ana
twelve feet above mean low water to
pass freely in and out of the tidal basin.
In connection with this lock, the bridge
contains a draw, which can be opened
whenever 1t is found necessary TO have
lar ger craft, such as dredges, etc, pass
eral hours to open and close this draw,
and during that time the bridge, OF
course, will be closed to traffic Such
action will not occur often, possibly not
more than once or twice a year, 50 that
the actual closing of the bridge to travel
will be almost negligible quantity The
roadway of the bridge is paved with
macadam, 80 as TO correspond with the
surface of Potomac drive. The entire
driveway, including the short section over
the bridge, has been oiled and smoothed,
by direction of Col. Cosby and is. now
in first-class condition.
Actual field work on the new structure
was begun in April, 1903. To prepare
a level of sixteen feet below mean low
water, SO az to provide a depth of seven
feet of water at the site OF the bridge
Nearly LOO piles. averaging fifty-..vc
feet in length, were driven to ten feet
below mean low water. A cofferdam was
built around the eastern half of the
foundation, the bottom leveled Off with
sand and five feet OF concrete placed
on top to seal the bottom. The water
was then pumped out Of the dam and
~ nj
concrete construction was in progress on
the eastern half. the cofferdam was com
pleted around the western half and con-
struction carried on as in the eastern
half. When the concrete bottom in the
west half was completed. the two Golfer
dams were united into one with an area
of 116 feet by - feet.
How the Gates Are Worked.
The lock and middle piers of each half
of the bridge and the abutments are
built of a cellular construction above the
level Of mean low water. On the river
side AID in each half of the bridge be-
You'd the railing and five feet below the
level Of the sidewalk is located a plat
form approximately nine feet by fifty-two
feet, on which is mounted the mechan-
.sm for operating the four curtain gates
located in openings eight feet wide. In
rear os each curtain gate is a set of
wooden gates OF the mitering type set
to operate automatically. In the center
OF the bridge IS q lock forty-siN feet eight
inches long by, twenty-siX feet wide. at
each end OF which is a set of gates. one
gate being stationary and the other
constructed so as to roll behind the sta
tionary cate, permitting an opening OF
twelve feet.
Tie roadway over the bridge is TWEEN
ty-hve feet wide and 1S4 feet long, with
sidewalks seven feet three inches wide
on each side. The railing on each side
OF the bridge is of ornamental concrete
between large concrete pedestals al tie
ends and oreN the center OF the bridge. In
inches on the sidewalk face OF the Two
pedestals on the tidal basin side ard at
the center Of the bridge are placed or
namen.al bronze fountains. the waste
water from which passes through the
pedcstaIs to an ornamental cast con-
crete head. from the mouth OF Which II
drips over cast corcrete panel. Both
head and panel are on the basin face
Of the bridge.
As explained by Maj. MORON. the enei-
neer officer in charge OF the structure
the curtain gates are intended 10 De
closed only when the water in the river
is highly turbid. in order to prevent the
sitting up OF the tidal reservoir and to
exclude flood waters. The automatic
tide and close during ebb tide. forcing
the water out OF the basin through the
outlet gates near 14t!l street at the head
of the Washington channel along the
Washington water front. The floor sys-
tenn over the lock In the new bridge is re-
movable to provide for the passage into
the tidal basin of large vessels the need
sufficient to justify the removal o. the