IMPROVEMENTS IN CONSTRUCTING SUBMERGED WORKS
Year: 1860

page_text: PROVISIONAL SPECIFICATION left by Joseph Gibbs at the Office of
the Commissioners of Patents, with his Petition, on the 12th July
1860.
I, JOSEPH GIBBS, of Brentford, in the County of Middlesex, Civil Engi-
neer, do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN CONSTRUCTING SUBMERGED WORKS," to be as follows:-
This Invention is for an improved method of constructing breakwaters,
barbours, piers, jetties, bridges, forts, defences, and other works under water
level by means of cassoons formed of distinct water-tight cells, which may be
floated to the proper site, and sunk by admission of the water, and the
cells afterwards separately emptied of water, and filled with concrete or other
permanent building material, and also by means of a cylinder coffer-dam wider
at the bottom than at the top.
To construct a breakwater or other submerged work, I cause a vessel or
cassoon of sheet iron, or other suitable material, to be built of a dimension
and of a breadth nearly in the form of a cube, or a triangle, or other convenient
form, and to rise above watermark when placed on its site. This cassoon
is divided into cellular compartments as shewn at Figure 1, Sheet 1, where
A, B, C, D, E, F, G, and H, form separate cells or compartments. Each of
these cells may be strengthened to resist the pressure of water by being lined
on the sides and bottom with well-burned and vitrified bricks laid in strong
cement or asphaltum, or other cementaceous material, or removable stays may
be used for the same purpose.

page_text: After a cassoon has been built, launched, and lined, or stayed in the manner
stated, it may be floated over the proper site; the cells may be gradually filled
with water, which will cause it gradually to subside until it has taken the
ground in the proper site. The cells, one by one, may then be emptied of the
water, and filled with concrete composed of clean shingle and hydraulic cement,
or other suitable material, until the whole, with the external casing, forms
one solid block.
The cells must be sufficiently numerous to prevent the cassoon from having
any tendency to float, or change position when any one cell is emptied of its
water. These cassoons may be joined, and also laid parallel to each other so
as to cover any requisite areas, or they may be placed in such a manner as to
form parallelograms or circles, or other figures, leaving an area, within
which may be filled rubble or shingle, and on which the superstructure or
other work may be wholly or partially raised.
When these cassoons are placed on banks where there is a probability of
the current moving the shingle or sand, it will be expedient to place groins at
right angles to the face of the work, or a foot may be built on the cassoon
as shewn at A, B, Figure 3, Sheet 1, which will indent in the sand or shingle,
and serve the purpose of sheet piling. The depth of the foot will depend on
the nature of the material on which the cassoon will have to be placed.
These cassoons may also be constructed of brick, stone, or other hard
material, well bonded with hoop iron ties, and an iron or wooden foundation
plate at its lower side, through which suspending rods are fixed.
In order to carry and deposit these brick or stone cassoons I construct
a transporting cassoon as described, Figure 6, Sheet 2. A, A, A, A, is the
foundation on which a cellular transporting cassoon B, B, is placed at a few
feet above low water, this cassoon divides in two parts at C, C, Figure 5,
for the purpose which will be hereafter described. It is also provided with
sluices so that the tidal water may flow in and out of it; it is also supplied
with two powerful latticed girders to keep the two parts in line with
each other, the brick or stone cassoon which is to be carried and deposited as
shown at D, D, and D, D, Figures 5 and 6, Sheet 2, and in the perspective
Drawing, Figures 7 and 8, Sheet 3 is bulged or joggled as shown at E, E,
Figure 6, Sheet 2, and Figures 7 & 8, Sheet 3. This bulge rests on the
sides of the transporting cassoon, which is properly strengthened in this part
to receive so great a weight. When the brick or stone cassoon is to be
moved, the sluices of the transporting cassoon are shut, the flow of the tide
will then lift the whole, and the brick or stone cassoon may be taken and
deposited on its intended site.

page_text: By filling with water the cells of the transporting cassoon it will gradually
sink, the brick or stone cassoon taking ground first, the transporting cassoon
will in the act of sinking glide down the slope of the brick or stone cassoon,
and the girder being so constructed as to allow the two parts to separate a
short distance so as to part from the joggles or bulges, air may again be
pumped into the cassoon to displace the water, and the transporting cassoon
will rise to the surface, and may be taken to its place for the purpose of again
transporting other like structures.
I would use also a cylinder coffer dam in the foundation of bridges and
piers. This cylinder has an outside case of iron wider at bottom than at top,
lined with brick, bonded and girded with iron; the lower edge is constructed
sharp for penetration, as shewn at A, A, Figure 4, Sheet 1.
The cylinder being brought to its site, the inside gravel, sand, or clay must
be scooped out, and the cylinder will then sink by the pressure of the
slope B, B, and when sufficiently deep, the space scooped out may be filled
with cement concrete in the usual manner.
In order to construct a foundation in deep water for a fortress or a jetty, or
other work of considerable extent, the separate cassoons may be placed in a
manner to form intervals between them equal to their width, as is shewn at
Figure 2, Sheet 1, where A, B, C, D, represent four of a series of cassoons,
and E, F, G, H, I, K, dams, piles, or coffers, for retaining such material as
is intended for filling the space E, F, G. The cassoons in this case form
the abutments for supporting the dams or coffers, and in order to fill the
spaces in the most effectual manner, I sometimes enclose in sacks recently
formed concrete before it is set, and pile them properly within the spaces so
as to fill it by setting and forming a solid mass.