Improvements in Foundations for Lighthouses, Piers, and the like.
Year: 1896

page_text: Date of Application, 26th Mar., 1896-Accepted, 2nd May, 1896
COMPLETE SPECIFICATION.
Improvements in Foundations for Lighthouses, Piers, and the like.
"
I, ALBERT FRANKLIN EELLS, of No. 101 Commercial Street, Boston, in the
County of Suffolk and State of Massachusetts, United States of America, Inventor,
do hereby declare the nature of this invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the following
statement:-
My invention relates to the construction of foundations for lighthouses, piers, and
the like, and is intended to provide means by which such structures can be located
at points ordinarily inaccessible and where such structures cannot be built in the
ordinary way by reason of storms, tides, currents, and the character of the
foundation, and by reason of deep water, sand, or mud, and because of the difficulty
in transporting the material and holding it in readiness for use in the building up
of such structures as ordinarily practised.
I have overcome the serious difficulties above enumerated by building the lower
part of the structure in some port adjacent to the land and secure from the
destructive operation of the waves, and this lower part I build as a floating
caisson, preferably of a flaring cylindrical shape, having double walls and with
an air-chamber arranged centrally of the structure with means for letting in the
water and discharging the air in the sinking of the structure, and with means for
removing the water when it is desirable to make it more buoyant, by compressing:
the air in the central chamber.
My invention includes special constructions and special method of use and.
manipulation, as hereinafter set forth.
I have illustrated the construction for my improvement in the accompanying
drawing, which shows a sectional view of the foundation, with the lighthouse or
upper structure shown as secured thereto.
In carrying out my invention, I construct the foundation part shown at A of
suitable material, preferably metal, and make it very strong, of any desired shape
in cross-section, though I prefer to make it of a circular cross-section, tapering:
from the bottom upward; and this structure is made with double walls, suitably
braced, with an interior space adapted to be filled with masonry, part of which is:
to be laid while the structure is in the harbor, for the purpose of ballast. An air-
tight top, having a manhole f, is provided for covering the upper part of the
caisson, and this has an air-tight door opening and closing from below.. A
temporary diaphragm or floor a is provided near the bottom of the structure,
within the lines of the walls, and this has a similar door or water-gate at b, the:
chamber between the temporary floor and the upper part of the structure, together.
with the space below, preferably being filled with compressed air while the caisson
is being towed to the place of the grounding, with the passage 6 of course open. A
series of pipes c extend down between the double walls of the outer casing to the
bottom thereof, and these pipes are connected with a suitable pump for pumping
away the sand and thus permitting the sinking of the structure to a solid or rock
foundation; or after the structure is weighted, water may be expelled by,

page_text: compressing the air, and workmen go down inside and either work a wrecking-
pump, or pick-and-shovel the material on which the caisson rests, to lower it to any
desired depth.
.
Suitable connections d are provided, for the attachment of the towing-ropes for
carrying the caisson to the place of sinking. The caisson may be made buoyant,
or made to sink low in the water, by manipulating the water-gate in the temporary
bottom, and by thus sinking it is protected from storms while in transit from the
place of construction to the place of sinking. When the proper location has been
reached, it is sunk to the bottom by permitting escape of air, and the pumps are
set to work to pump out the sand through the series of pipes c, which causes the
caisson to settle; and while this operation is going on, water may be pumped into
the interior chamber, which will give stability to the structure while it is being
anchored. After the caisson has grounded, the filling of the space in the walls is
completed, with masonry. This renders the structure solid on its foundation, and
secure against disturbance by the swells or waves, while the main masonry structure
is building in the body of the caisson. The temporary bottom is then removed, and
the interior space is also filled up with concrete or masonry, or with sand or mud,
this forming a combined metal. and masonry foundation, and the masonry foundation
will be permanent even after the outer metal has been worn away. During the
sinking operation, the structure is suitably anchored by guy-ropes e running off to
stationary anchors.
During the operation, should the central chamber become obstructed by the
sand in the bottom thereof, a branch pipe from the sand-pump can be extended
through the hatch f, and the sand or mud at the bottom be removed.
It will be noticed that with this structure, absolute control is provided, and in
sinking the caisson, should one side sink faster than the other, it is only necessary
to stop the pumps from working on one side and keep those at work on the other
side until the structure begins to sink on a level.
In case the location is shown to be impracticable, then air may be pumped in,
sufficient to float the structure to another location. This may also be done, by
removing the inner filling, at any time after the structure is completed, should
it become desirable because of the shifting of the channel, or for any other
reason.
The superstructure may be of any desired kind. I have shown a tower or
lighthouse, the bottom of which is formed by the top of the caisson.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what I
claim is :-
1. A floating caisson having double walls, a temporary bottom, a central closed
air-chamber formed by the walls of the caisson above said bottom, and means for
floating said chamber, substantially as described.
2. The floating caisson having double walls and a central air-chamber, and a
series of pipes extending downwardly between the double walls to points directly
beneath the bottom of the caisson, whereby the material below the edges of the
caisson may be removed, substantially as described.
3. In combination, the upper shell having the closed bottom, the support therefor
comprising the truncated conical double shell and the temporary floor secured near
the bottom of said conical shell, whereby an enclosed.space is formed between said
temporary floor and the floor of the upper shell, substantially as described.
. 4. In combination, the upper shell provided with pumping appliances, the base
comprising the double conical shell and the pipes extending between said walls of
said double shell, the upper part of said pipes being in communication with a
pumping appliance, substantially as described.
5. The method of constructing a sub-aqueous foundation, consisting in the use of
a double-walled caisson having a covered interior, in weighting the caisson by
partially filling the space in the double walls, sinking the caisson in place, then

page_text: completing the filling of the interior of the wall space, and finally filling the centre
of the caisson, substantially as described.
Dated this 14th day of March 1896.
ALBERT FRANKLIN EELLS.
Haseltine, Lake & Co.,
45 Southampton Buildings, W.C., Agents for the Applicant..