IMPROVEMENTS IN THE CONSTRUCTION OF BRIDGES AND WORKS OF A SIMILAR NATURE
Year: 1822

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
DOWELL MOXON, of Liverpool, in the County Palatine of Lancaster, Ship
Owner and Merchant, send greeting.
WHEREAS His most Excellent Majesty King George the Fourth, by
His Letters Patent under the Great Seal of Great Britain, bearing date
at Westminster, the Ninth day of November, in the third year of His
reign, did, for Himself, His heirs and successors, give and grant unto me,
the said John Dowell Moxon, His especial licence that I, the said John
Dowell Moxon, my executors, administrators, and assigns, or such others
as I, the said John Dowell Moxon, my executors, administrators, or assigns,
should at any time agree with, and no others, from time to time and at all
times during the term of years therein expressed, should and lawfully might
make, use, exercise, and vend, within that part of our United Kingdom of
Great Britain and Ireland called England, our Dominion of Wales, and
Town of Berwick-upon-Tweed, my Invention of "IMPROVEMENTS IN THE
CONSTRUCTION OF BRIDGES AND WORKS OF A SIMILAR NATURE;" in which said
Letters Patent there is contained a proviso obliging me, the said John
Dowell Moxon, by an instrument in writing under my hand and seal,
particularly to describe and ascertain the nature of my said Invention, and in
what manner the same is to be performed, and to cause the same to be inrolled
in His Majesty's High Court of Chancery within six calendar months next
and immediately after the date of the said recited Letters Patent, as in
and by the same, reference being thereunto had, will more fully and at large
appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
John Dowell Moxon, do bereby declare that the nature of my said Invention,
and the manner in which the same is to be performed, is described and
ascertained as follows (that is to say):-
My aforesaid Invention consists of a coffer dam, composed of timber framed-
work, without bottom, otherwise built like a lighter, of any required depth,
to be opened and shut by a hinge or other convenient mode when in a floating
condition, which frame is to have a number of iron or wooden piles attached
to it to move in loops if necessary in order to fasten or attach it to the bottom
or bed of the river when grounded by the fall of the tide. These piles are
to project some feet above low-water mark for the convenience of driving
them after the coffer dam or framework has taken ground. This coffer
dam or framework is made at bottom in form of a wedge, so as to cause it
to enter or cut into the bed or bottom of the river, and the piles are then
driven to render the whole apparatus stationary. When this is done the
dam is so constructed that by a vacancy which is left between its external
and internal timbers, the whole may be rendered sufficiently water-tight by
allowing clay, &c., &c., to be poured in, and so continued until there is enough
to lodge all round the inside of the wedge; and the annexed Drawings, from
No. 1 to 5, shew the nature of the framework in detail. No. 6 is a per-
spective view of the general structure, and No. 6, Figure 2, an horizontal
plan of the same. The nature of the iron piles may be seen from the hinge
No. 6, though they are not meant to be higher than six feet above low-water
mark.
The next prominent part of my Invention consists in combining iron
and stone in such a manner as to produce great strength and solidity in piers,
by coating or facing their external surfaces with cast iron, and as the stone
requires a portion of cement this will allow ample room for the contraction
and expansion of the iron. (No. 7) will shew the manner of connecting one
layer of stones and iron, which will lead to the forming an intire pier. I
must here remark, that each stone, to the distance of four feet or more into
the interior of the pier, is surrounded with cast iron of three quarters of an
inch thick more or less, and the outside of six inches or any other convenient
and needful strength. This will equal about one and a half inches between
each stone. This one and a half inches should be clamped together from
stone to stone by cast iron, as seen in the Drawings. These clamps will also
be generally below the level or horizon of each course, and will give a solidity
to the iron and stone not attainable by lead or other materials which have
been heretofore used in such works. The inside part of these casings or coatings

page_text: of cast iron being also formed so as to prevent the stone from moving, are
in return prevented by the stone from moving outwards. "Tis thus evident
that they form a mass of security and strength, and a wall of this description
in fortification, and on an angle of forty-five degrees or thereabouts, would
for an age resist shot of every description. In building layers of the above
great care is necessary to prevent lodgements of water at the external surface;
but this can easily be accomplished by holes being formed in the upper layers,
and short spikes or studs to fit them in the lower ones. This would also
give still greater security to the whole, and assist to bind one stratum to the
other. "Tis evident that inferior stone can be used thus coated, for being
shielded by the iron from the atmosphere and from the effect of ice or frost,
no material pulverization or decay can take place. And as it is proposed to
cover the pier intirely with cast iron prior to springing the arch, as the whole
will settle in one mass and the arches press equally, this effect would also
be heightened by the lowest stratum of the piers being of cast iron in particular
and difficult situations. The piers of bridges may, however, be constructed
with iron boxes or troughs on the principle hereafter noticed in the building
of arches. No. 8 shews seven layers, with the mode in which iron is com-
bined with the stone, and these are clamped or otherwise secured to the inner
courses of the masonry.
I will proceed to describe the mode of forming arches, and the spandrills
or spaces between the arches, each part joining by groves and reeds or ribs
until the whole structure is united into a compact body without screw or
cement; that is to say, the groves cast in the arch pieces will exactly join the
reed pieces between these arches so as to join with facility; nor are the
separate pieces to join merely in forming the arch, but each is to join in
the same manner the whole width of the bridge; and as from the nature of
the pieces expansion or contraction will take place principally in the hollows
of the mass, and consequently little external expansion or contraction will be
perceptible, hitherto not attainable in iron bridges, because the bolts compell
the pressure to act principally in one direction. The Drawing No. 9
will shew the nature and form of the arch pieces, with the grooves or
channels wherein the ribs or braces between the arches No. 10 are fitted,
and the external ribs are cast to resemble cut stone. These ribs are.in general
to be joined in three pieces lengthways, and cast in two or more ribs joined
together to prevent all lateral action in fixing, or, in other words, to prevent
vibration. The ribs are also cast of unequal lengths, that their intersections
may give strength and prevent any derangement of the parts. The next
feature of my Invention is, that the iron flooring for supporting the roadway

page_text: is not at top, but forms the boundary of the under part of the arch, and
has thus the appearance of stonework. Thus when the road is filled up and
falls down into the spaces between the ribbs and boxes of the arch, &c., &c.,
there will be no tremulous motion, nor the noise peculiar to iron bridges
when heavy carriages are passing over them. In coming to the upper
stratum, or that over or above the crown of the arches, the ribs or beams
will then begin to cover the whole upper surface from end to end of the
bridge, as seen in No. 11, and the footpath is to be erected on three or four
of these ribs crossways by thin plates of cast iron which have grooves to
receive the said ribs, and on these plates the stones are to be placed, unless
iron is preferred, which can be roughed, and rendered neat, safe, and as clean
as stone. The Drawing No. 11 is a supposed transverse section of an arch,
and shews the first great chain or range of ribs extending across the bridge;
the groves are seen and the reeds also. The only difference in the Drawing
is, that the grooves of the boxes of the arch are seen internally, but in real
building are placed externally; boxes of unequal size, with grooves at equal
distance, will break the joints and give the required stability; the fronts of the
boxes are also taken off to shew the nature of their formation. The facility
of this mode of joining will give in building will amply compensate for the
additional price of such castings. The Drawing No. 12 shews three ribs with
reeds fitted to slip into the groves or channels of the arch, also reeds at bottom
to fit the layer below, and are broke in the middle to shew that they can be
joined to any length. The groves of these ribs may also be seen above to
receive the reeds of the successive course. In extending this system to light-
houses, casts of the proposed situations can be taken when of rock in its
natural form without much dressing or levelling, which will make the work
stronger; and in foundations of softer matter iron joined in one intire mass
will form a good foundation for any superstructure, since no part can sink
without the whole, and the foundation or bottom plates can be placed and
affixed to the usual precaution of piles either of iron or wood.
I do again declare, that my Invention consists of a moveable coffer dam to
open at each end, and without bottom, with internal or external piles, or both
at option, to drive after the framework has grounded upon the bottom or
bed of the river, and for rendering the same machine capable of removal to
any other situation without being taken to pieces; and for coating stone piers,
wharfs, or other works of a similar nature with cast iron; also for constructing
bridges, wharf walls, piers, and works of a similar nature of cast iron, on the
principle of avoiding screws, bolts, nuts, or rivets; and for applying cast iron
in the manner herein-before mentioned for fortification and lighthouses. The

page_text: form, size, and proportions of the various parts of the bridge or other works
may be altered, according to the discretion of the engineer or architect employed
in crecting the same, or according to the nature, extent, and situation of the
bridge or other structure, without departing from the object of my Invention
as herein-before described and set forth.

page_text: Pier shewing a convenient mode of
securing the cast iron coating or
Lacing upon the Stone work

page_text: spaces between the arches, these boxes or troughs have needs or projections
Cust upon them which projections are adapted to enter into grooves or channels formed
upon the upper edges of the boxes or troughs which form the keystone/Course of the arch