IMPROVE- MENTS IN THE CONSTRUCTION OF PIERS, WALLS, AND OTHER SIMILAR STRUC- TURES, AND OF LANDING STAGES, AND IN THE CONNECTIONS THEREWITH OR ATTACHMENTS THERETO
Year: 1863

page_text: LETTERS PATENT to Robert Trefusis Mallet, of 11, Bridge Street, in the
City of Westminster, Civil Engineer, for the Invention of "IMPROVE-
MENTS IN THE CONSTRUCTION OF PIERS, WALLS, AND OTHER SIMILAR STRUC-
TURES, AND OF LANDING STAGES, AND IN THE CONNECTIONS THEREWITH OR
ATTACHMENTS THERETO."
Sealed the 10th November 1863, and dated the 15th May 1863.
PROVISIONAL SPECIFICATION left by the said Robert Trefusis Mallet
at the Office of the Commissioners of Patents, with his Petition, on the
15th May 1863.
I, ROBERT TREFUSIS MALLET, of 11, Bridge Street, in the City of West-
minster, Civil Engineer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE CONSTRUCTION OF PIERS, WALLS, AND OTHER SIMILAR
STRUCTURES, AND OF LANDING STAGES, AND IN THE CONNECTIONS THEREWITH, OR
ATTACHMENTS THERETO," to be as follows:-
This Invention relates to a method of constructing the walls for landing
stages, piers, quays, and other submerged or partially submerged structures of
a like nature, and to floating landing stages, and their connections therewith
or attachments and approaches thereto.
In constructing the walls.stages, or for other purposes herein-before referred
to, I put in the foundations by the known method of a series of wrought-iron
caissons, sunk close to one another, but with this improvement, that I make
these caissons of much longer sections than has heretofore been usual, say,

page_text: 45 feet, and sink them with their ends as close to one another as possible.
The coffer dam, from the top edges of these caissons to above high-water mark,
is constructed of large compound wrought-iron plates, built up of several of
the plates well known as Mallet's buckled plates, and all similar and inter-
changeable. They may be, say, 15 feet square. The guide piles for the
lower caissons are driven at equal distances, say, 15 feet apart, along the back
and front of the intended wall, and opposite one another in pairs, and are
recessed to take a plate or beam of iron, to either side of which are bolted as
many of the compound plates say, two, as may be necessary to make up the
requisite height of damn, and they are bolted in such a manner as to enable
the plates at either side to be taken off without prejudicing those at the other
side. The aforesaid iron plate or beam between them is sufficiently wide to
have its inner edge projecting, aud giving the means of attachment for other
plates, to be hereafter described. Thus a continuous double line of water-
tight wall is formed, open at both ends, of indefinite length, and capable of
being taken from at one end and added to at the other.
To commence
operations, a part of thiswall included between any two opposite pairs of guide
piles is partitioned off by bolting, say, two, of the compound plates to the
inner edges of the aforesaid plate or upright bar, which is inserted in the guide
piles. A closed rectangular coffer is thus formed, from which the water is
removed, and the wall built up and left hacked off at the ends. To continue
the wall into the next section without breach of continuity in the masonry, a
part of the back of the wall near the racked end, say, one of the counter forts,
is built up tight against the coffer, and a recess may be left in it for puddle or
other caulking material. Between the face of thewall and the nearestopposite
guide pile a diaphragm built of buckled plates is bolted to the inner edge of
the aforesaid upright bar, of such a shape as to nearly fill the space between the
face of the wall and the front of the coffer, but to leave a space of a few inches
between its inner edge and the face of the masonry, to allow for inaccuracies
in its building, this space is made water-tight by a series of moveable adjust-
able plates attached to it,having on their edges next the wall a flap or strip of
thick vulcanized india-rubber, which, by its elasticity and the pressure of the
water, shall always bear against the face of the wall. It is obvious that this
diaphragm, with the aforesaid counterfort, form a complete division between
the back and front of the dam, and between them and the cross compound
plate at the further end of the wall; the water can now be admitted, and the
second rectangularsection of the continuous dam having been completed and
emptied of water, the cross compound plate separating it from the first section
can be removed, and the masonry can be carried on in to it without break,

page_text: respec-
and this process can be continued indefinitely. The "dummy" of the floating
landing stage may be of any convenient construction, a portion of the surface
being recessed to receive the approaches, and decked over below at such part.
According to another part of my Invention, I propose to attach or move
floating landing stages to the shore by means of a system of diagonal bracings,
forming a framework which is to be hinged to the shore "dummy"
tively, so as to form a rigid connection or mooring with the shore, as regards
any horizontal movement of the "duminy," whilst free play in a vertical
direction is allowed for the rise and fall of the tide. This system of mooring
forms the support also for the approaches, for which purpose I propose to
cover it either with plain floor planking attached rigidly to it, or each plank
being laid parallel to the face of the wall is made to turn on an axis parallel
to its length by being connected with the rest by rods or links, the points of
connection having the same distance from centre to centre as the axes, and
being all the same distance above or below their corresponding axes. By this
means a parallel motion in the several planks is obtained, so that they will
form a level gangway when the "dummy" is even with the quay or wall, and
a series of steps in any other position. In some cases I propose to make each
step or grade sufficiently wide to take an ordinary vehicle or waggon, and to
hinge the contiguous ends of Numbers 1 and 2 steps (say,) with a moveable
landing or platform, the opposite end of Number 2 and the contiguous end of
Number 3 being also hinged to another similar platform or landing, and so
on throughout the series. These platforms or landings having the same
parallel notion herein-before described, the intermediate roadways (Numbers
1, 2 and 3) will form a zig-zag inclined rump passable for horses and
vehicles.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Robert Trefusis Mallet in the Great Seal Patent Office on
the 14th November 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
TREFUSIS MALLET, of 11, Bridge Street, in the City of Westminster, Civil
Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifteenth day of May, in the year of our Lord
One thousand eight hundred and sixty-three, in the twenty-sixth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto

page_text: me, the said Robert Trefusis Mallet, Her special license that I, the said
Robert Trefusis Mallet, my executors, administrators, and assigns, or such
others as I, the said Robert Trefusis Mallet, my executors, administrators,
or assigns, should at any time agree with, and no others, from time to time
and at all times thereafter during the term therein expressed, should and
lawfully might make, use, exercise, and vend, within the United Kingdom
of Great Britain and Ireland, the Channel Islands, and Isle of Man, an
Invention for "IMPROVEMENTS IN THE CONSTRUCTION OF PIERS, WALLS, AND OTHER
SIMILA STRUCTURES, AND OF LANDING STAGES, AND IN THE CONNECTIONS THEREWITH
OR ATTACHMENTS THERETO," upon the condition (amongst others) that I, the said
Robert Trefusis Mallet, my executors or administrators, by an instrument in
writing under my hand and seal, or under the hand and seal of one of them,
should particularly describe and ascertain the nature of the said Invention,
and in what manner the same was to be performed, and cause the same to
be filed in the Great Seal Patent Office within six calendar months next
and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Robert Trefusis Mallet, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and by
the following statement, reference being had to the accompanying Drawings,
and to the letters and figures marked thereon, that is to say):-
My said Invention relates to a method of constructing the walls for laud-
ing stages, piers, quays, covered ways, sewers, or tunnels, andother submerged
or partly submerged and subterranean structures; also floating landing stages
and the connections therewith, and attachments or approaches thereto.
In putting in the foundations for walls, piers, and similar structures herein-
before referred to, I employ the known method of a series of iron caissons
sink close to one another, but I prefer to make these caissons of much greater
length than has heretofore been usual. The peculiar coffer dams which form
part of the subject of this Invention are built ou the top edges of these
caissons as high as may be desired, and are bolted thereto. They are con-
structed in large sections similar and interchangeable, made of a strong frame
of iron covered with metal plates, preferably those known as Mallet's buckled
plates. The guide piles are driven opposite one another along two opposite
sides of the intended wall or other structure at intervals equal to the length
of one of the aforesaid sections of the dam, and are designated to allow a plate
or beam of iron to slide down between them to either side, of which plate or
beam are bolted the ends of as many of the aforesaid sections as may be
required to make up the necessary height of the dam. The sections are

page_text: connected in such a manner as to enable those at either side of the plate or
beam to be taken off without interfering with the sections at the opposite side
thereof. In some cases the aforesaid plate or beam between the sections has
its inner edge projecting and gives the means of attachment for the ends or
cross partitions of the several divisions of the coffer dam, which partitions are
constructed in large sections similar to or identical with those forming the
sides of the dam. Thus a continuous double line of water-tight coffer dain
is formed capable of being taken from at one end and added to at the other
as the work proceeds. The cross partitions above referred to are connected
with the sides of the dams between any two opposite guide piles, and are thus
made to enclose a space, or form a complete coffer dam of any length,
measurable by the intervals between the piles on the same side of the dam.
These partitions are connected to the sides of the dam by being bolted to the
intermediate plate or beam above referred to, and to the upper edges of the
ends of the lower caisson, the length of which must be regulated so that its
ends shall always lie between two opposite guide piles. The dam so formed
should be securely shored and strutted inside. This division of the dam is
then emptied of water and the ground excavated inside until the dam has
sunk has deep as may be desired for the foundations of the intended work.
If the area enclosed be long enough to contain the whole wall or other
structure, such for instance as the pier of a bridge, the dam may be removed
as soon as the work is complete, but if the structure or wall be of considerable
length, such for instance as a long pier, embankment wall, or a submerged
tunnel it will be more convenient to make the parts of the dam serve re-
peatedly by continually removing them from one end where the work is
complete, and re-erecting them in advance of the work at the further end of
the dam. For this purpose a second division of the dam similar to the first
is erected over the next of the lower caissons and is undersunk as before to
the same level as the first. The adjoining ends of the two divisions of the
dam may now be removed and the wall or other structure being now built up
in the first division, but left with its ends sloped or racked off, is carried
forward continuously into the second d'vision; a partition or dam is now con-
structed across the inside of the first division either by building the wall up
against the sides of the division or by inserting one or more diaphragms,
having their edges at one side made water-tight against the surface of the
wall, and their edges at the other side bolted to the edges of the intermediate
plate or beam herein-before referred to, in the sides of this division of the
coffer dam. Or both these methods may be adopted in conjunction. This
cross partition or dam should be made as close to the second division as con-

page_text: venient. As soon as this cross partition or dam is completed the whole of
that part of the first division of the coffer dam which is on the side of the
cross partition or dam furthest from the second division can be removed and
carried forward to form part of a third division. That part of my Invention
which relates to the floating vessels, or dummys as they are sometimes called,
of landing stages consists in making them with a portion of the deck surface
depressed to receive the approaches and connexions as herein-after described.
Another part of my Invention consists in attaching or mooring floating
landing stages to the shore solely by means of a system of diagonal bracing
forming a framework which is to be hinged to the shore and dummy respec-
tively, thus preventing any horizontal movement of the dummy, whilst it is
allowed free play in a vertical direction for the rise and fall of the water
surface. This system of inooring forms also the support for the approaches,
for which purpose I propose to cover it either entirely or partly over with
either a plain surface of planking or other material, or with planks laid
transversely to the line of approach, and each plank made to turn or rock on
an axis parallel to its length by being connected to the others by rods or links,
the points of connection having the same distance from centre to centre as the
axis, and being all the same distance above or below their corresponding axes.
By this means a parallel motion is insured in the several planks so that they
form a level gangway from the quay wall to the floating stage, when this is at
its highest level and a flight of steps with greater or less vertical rise between
ench step when it is at any other level. In some cases I propose to make
each step or grade sufficiently wide to take an ordinary vehicle or waggon
and to hinge the contiguous ends of Nos. 1 and 2 steps (say,) to a common
moveable landing or platform, the opposite end of Number 2 and the con-
tiguous end of Number 3 being also hinged to another similar landing or
platform, and so on throughout the series. These landings or platforms having
the same parallel motion herein-before described, the intermediate roadways,
Numbers 1, 2, 3, &c. will form a zig-zag inclined ramp passable for horses
and vehicles.
And in order that my said Invention may be fully understood I shall
now proceed more particularly to describe the same, and for that purpose
I shall refer to the several Figures on the Sheets of Drawings hereunto
annexed, the same letters of reference indicating corresponding parts
throughout all the corresponding Figures.
Fig. 1, on Sheet of my Drawings, is a sectional plan of the system of
coffer damming adapted for the building of a continuous line of wall or
structure. Fig. 2 is partly an exterior side elevation and partly a sectional

page_text: any
elevation of the interior of the dam, and Fig. 3 is a cross section of the dam
and wall. A, A, B, B, C, C, D, D, E, E, and F, F1, are the opposite
pairs of guide piles which may be of timber or iron and of convenient
form, as shown at C, Figure 7, or E' and F¹, Figs. 7 and 7a (Sheet 2), that
will admit of their serving as guides, in which the piece of iron which serves
to connect the several members or sections of the coffer dam may slide
vertically. This piece of iron slides in a groove as shown at K1, K2, and
K³, Figs. 7 and 7. The frames of the several sections of which the coffer
dam is composed are covered with buckled plates, nine of these bucklesbeing
shewn in my Drawing as covering one section. The edges of the sections
are of iron and the cross or intermediate bars of the frame are of T iron,
but these parts may be of any stronger section to suit circumstances The
top and bottom edges have a single row of bolt holes shown at a, a, Figs. 7
and 7 and a row of bolt holes is also made in the vertical or end edges, but
in the vertical edges each alternate hole only is used at a time, as shown in
Fig. 10. The piece of iron r which slides in the pile has a row of corres-
Ponding bolt holes to those in the vertical edges, but they are countersunk on
opposite sides of the piece alternately to receive the square heads of the bolts.
Thus when a plate is bolted to either side of the piece another row of
empty bolt holes, as in Fig. 10, will always be prevented, by which another
plate may be attached at the other side, and so either may be detached
without disturbing the other as herein-before described. All these joints may
be filled in with a packing of oakum, soft wood, metal, or other suitable
material. Where the wall is to be curved this packing or filling may be
made thicker in the vertical joints at the outer side of the curve, as shown in
Fig. 8, or it may be necessary to make the sections at that side longer than
those at the other side. L, L, Fig. 7a and 7b are L irons bolted to the inner
edge of the connecting pieces r, r, and to them are bolted the cross partions
as at M, M. Where two such cross partitions or ends adjoin, the second must
be connected directly with the side by the Liron N, which is not bolted to
the piece r, but only to the vertical edge of the side section T, the heads of
the bolts being inside the dam aud the points screwed into a loose vertical rib
or bar S. The adjoining corners of the left hand coffer are thus free to slide
in the angle formed by the face of the pile and the piece r, whilst the adjoin-
ing ones of the first division slide independently as before described in the
grooves of the two piles.
The connection of the parts by bolts are shewn in the smaller scale by short
red lines. The lower caisson has its outer surface flush and even, and it may
be of cast or wrought iron, and may be all in one piece, and all left in the

page_text: ground and form part of the wall or structure, as in Figure 3; or it may be
made of several pieces bolted together, some or all of which may be removed
and saved after the completion of the masonry. Supposing that the wall has
been built in the first section of the dam, and that its end is racked off in a
slope, as shown in Figure 1, the cross diaphragms or bulkheads O, P, are now
adjusted to the surface of the wall; they are bolted to the inner edges of the
pieces in the manner shown at L, M, Figures 7 and 7b, and the joint at
the surface of the wall may be made water-tight, either by clay puddle, as
shewn in Figure 5, and at R, Figure 1, or by an exterior flap of thick vul-
canised india-rubber or other suitable material n, as in Figure 4. This flap
always bears against the wall by its own elasticity and by the pressure of the
water, and may be secured to a series of moveable or adjustible plates S, S,
Figures 1, 3, and 4, which can be moved up into contact with the wall and
there bolted tight, thus providing for slight variations in its contour. After
these diaphragms or bulkheads have been secured and shored or strutted the
whole of that part of the division of the dam which is outside them, and
shewn in dotted lines in Figure 1, may be removed. Meanwhile a second
division of dam B, E, E, B', has been undersunk, and when it is down in its
place the ends V and W may be removed (by preference at low water) by
unbolting the part N from the bar or ribs, and detaching the end W from the
piece r, inserting packing in the space previously occupied by S, and bolting
the side 'T' to the section U directly through the spare bolt holes previously
referred to. The wall may now be carried on continuously into the second
division of the dam, and when it has been built up to the other end of this
division, and there racked off as before, other diaphragms may be adjusted at
the piles C, C, and so on. The wall may be so short as to require but one
length of dam, such, for instance, as the pier of a bridge. In this case the
connections of the large plates, of which the dam is composed, may be of a
simpler character, as shewn in Figures 6 and 9, Sheet 2. The wall or walls
may also be of any form or section, hollow or solid, and may be built at any
depth below the water or below the surface of the soil, and may be formed of
iron, stone, brickwork, or other suitable material. The lower caisson may
either be left in the ground and form part of the structure itself, or it may be
removed, if preferred.
My improved floating stage is shewn in plan at Figure 11, and cross section
at Figure 12. The depressed part is lettered a, b, c, d, e, e, are girders hinged
at one end to the barge or dummy, and at the other to the wall or pier, and
are strongly secured thereto by the anchoring bolts ff. These girders are
braced diagonally at u, u, Figure 11, so as to form a rigid system and con-

page_text: 1
stitute the only connection or mooring for the barge. This has the advantage
of dispensing with all chains and anchors, dolphins, or guide piles, or any
other obstruction to the stream or tideway. They may be covered with a flat
surface of planking, asphalt, or other material, or they may carry saddles g, g,
(Figures 13 and 14) on their upper sides, in which the steps h, h, rock. These
steps are either connected above by the hand railing at i, i, (Figure 12), or
below at k, k, Figures 12, 13, and 14, by means of the connecting rod l, m,
or the two may be combined. The point m is vertically below the centre t,
round which the girder turns, and she distances k, k, being equal to g, g,
and k, g, to k, g, the whole forms a parallel system, and the steps always
remain level, as shown by the red and dotted lines in Figures 12 and 13.
Having now described and particularly ascertained the nature of my
Invention, and the manner in which the same is or may be used or carried
into effect, I would observe in conclusion that what I consider to be noval
and original, and therefore claim as the Invention secured to me by the
herein-before in part recited Letters Patent, is,-
1st, the general system or mode of constructing piers, walls, and other
similar solid or hollow structures, substantially in the manner herein-before
described and illustrated by my Drawings.
2nd, the application and use of the peculiar construction of continuous
undersunk coffer dams composed of iron or other metal in combination or
not with other materials in the building of piers, embankment walls, and
similar structures, substantially in the manuer herein-before described.
3rd, the constructing of iron or other metal coffer dams for piers, walls,
and similar structures in sections of single thickness bolted together, as
herein-before described.
4th, the application and use of water-tight partitions, diaphragms, or
bulk-heads of iron or masonary in combination or not with other materials
between the surfaces of the structure and the interior of the coffer dam,
substantially in the manner and for the purpose herein-before described.
5th, the application and use, in combination with the water-tight parti-
tions, diaphragms, or bulkheads above referred to, of plates made adjustable
to suit the surface of the wall or other structure, in the manner and for the
purpose herein-before described.
6th, the application and use, in combination with the water-tight parti-
tions, diaphragms, or bulkheads, above referred to, of a flap of vulcanised
india-rubber or other suitable material material in combination or not with
adjustable plates for the purpose of obtaining a water-tight joint, as herein-
before described.

page_text: 7th, the system or mode of mooring floating landing stages or dummies
by means of their approaches only, as herein-before described.
8th, the peculiar construction and arrangement of the steps or surfaces
of the approaches to floating landing stages or dummies, as herein-before
described.
In witness whereof, I, the said Robert Trefusis Mallet, have hereunto
set my hand and seal, this Fourteenth day of November, in the
year of our Lord One thousand eight hundred and sixty-three.
R. T. MALLET. (L.S.)