AN IMPROVED SYSTEM OF CONSTRUCTING CAST AND OTHER IRON BRIDGES, VIADUCTS, AND OTHER SIMILAR STRUCTURES
Year: 1865

page_text: LETTERS PATENT to William Brookes, of 62, Chancery Lane, in the
County of Middlesex, Civil Engineer and Patent Agent, for the Invention
of "AN IMPROVED SYSTEM OF CONSTRUCTING CAST AND OTHER IRON BRIDGES,
VIADUCTS, AND OTHER SIMILAR STRUCTURES."-A communication from abroad
by William Cowell Teasdale, of Bude, Hungary, in the Empire of
Austria.
Sealed the 23rd February 1866, and dated the 30th August 1865.
PROVISIONAL SPECIFICATION left by the said William Brookes at the
Office of the Commissioners of Patents, with his Petition, on the
30th August 1865.
I, WILLIAM BROOKES, of 62, Chancery Lane, in the County of Middle-
sex, Civil Engineer and Patent Agent, do hereby declare the nature of the
said Invention for "AN IMPROVED SYSTEM OF CONSTRUCTING CAST AND OTHER
IRON BRIDGES, VIADUCTS, AND OTHER SIMILAR STRUCTURES," communicated to
me from abroad by William Cowell Teasdale, of Bude, Hungary, in. the
Empire of Austria, to be as follows:-
The improvements relate to the application of the principle of statics
according to which the stress produced by inherent as well as extraneous weight
acts in the direction of the neutral axis of the iron tubes or cylinders com-
posing this arched system of construction, combined with a contrivance for
controlling expansion and contraction.

page_text: Figure I. is a geometrical elevation of the whole construction; Figure II. a
part of a normal section; Figure III. an elevation of a single arch piece
*voussoir" with connection to right and left; Figure IV. part of plan and
elevation showing the expansion contrivance in centre of arch (Figures II.
and III. being on an enlarged scale), reference being likewise had to the letters
of reference marked thereon.
The Invention consists in applying the round or polygonal hollow cylinder
or tube of the above description of material so as to bring solely its neutral
axis into combination, that is to say, the leading element of this construction
is the iron or-cast-iron cylinder or tube, in which merely resistance to com-
pression through its length is brought into action without relying on its lateral
or cohesive strength. To make the advantage manifest, the illustrative
comparisons, Figures a, b, c, are subjoined.
In these three Figures W, W¹, W", denote loads of equal weight in
avoidupois, and C, C¹, C, round cylinders or polygonal tubes of the same lengths
and same diameters or sides; the length of any such cylinder or tube is how-
ever never to surpass 12 times its diameter. It is obvious that the greatest
possible resistance such cylinder or tube is capable of is that which it opposes
to compression (Figure C). With these introductory remarks the description
of this new system of construction is proceeded with in a manner to give a clear
insight to those of the profession into the Invention.
Construction. The basis of this construction is the arch; in this arch all
that merely augments its inherent weight without contributing in any way to
its strength shall be eliminated. The statical lines, i.e., the "extrados," as
well as the "intrados," are constructed of one, of two, or of any greater number
of series of cylinders, according to the length of the span and other exigencies
of the particular cases, see Figure I. of accompanying Drawing. The con-
centric arcs of the superior as well as of the inferior series are composed of
the above-named cylinders or tubes. The normal lines drawn to those con-
centric arcs represent iron or cast-iron plates, P, P, Figures II. and III., which
in being fastened to the cylinders a, a, by screw bolts s, s, s, form the single arch
piece (voussoir.") Figure III., and the required number of these arch pieces
when fastened to each other shall form an arched truss. The geometrical
elevation of such a truss is represented by Figure I.; Figure II., shows the
connection of these, trusses amongst each other.
Now, it is evident that in this construction the stress produced by inherent
weight as well as extraneous, load will work in the direction of the neutral
axis of the tubes, and that this stress therefore, will act upon the greatest
possible resistance of the metal under consideration.

page_text: Expansion and contraction.-But in order to make practical use of this
system of construction it becomes indispensable to combine it with a con-
trivance to control expansion and contraction of the metal in a manner to
keep the interior construction as well as the abutments in stone masonary
sound and safe from such effects; this is purposed to be done in the way.
following:-The bridge or viaduct is constructed in two perfectly separate
parts A, A, almost in the manner of a pair of hinges (in this case, however,.
without the connecting bolt), see Figure I., but particularly Figure IV. The
semi-trusses composing each half of the bridge terminate on their highest point
alternately in concave and convex ends, so as to fit exactly into each other.
The extremities of the bridge are completely rounded off, and fit exactly into
the concave cast-iron butts D, D, Figure I., fastened to the abutments. There
will be, therefore, a moveable rotation axis C common to the two parts of the
construction, and two fixed rotation axes R, R,, on each end of the bridge,
Figure I. In this manner the whole construction shall in its centre spon--
taneously rise when its two perfectly rigid balves are expanding, and retrocede
to the proper point when they are contracting, without injuring any part of
the edifice..
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Brookes in the Great Seal Patent Office on the
28th February 1866.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
BROOKES, of 62, Chancery Lane, in the County of Middlesex, Civil Engineer
and Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters.
Patent, bearing date the Thirtieth day of August, in the year of our Lord
One thousand eight hundred and sixty-five, in the twenty-ninth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,.
the said William Brookes, Her special licence that I, the said William
Brookes, my executors, administrators, and assigns, or such others as I, the
said William Brookes, my executors, administrators, and 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 "AN.
IMPROVED SYSTEM OF CONSTRUCTING CAST AND OTHER IRON BRIDGES, VIADUCTS, AND

page_text: OTHER SIMILAR STRUCTURES," communicated to me from abroad by William Cowell
Teasdale, of Bude, Hungary, in the Empire of Austria, upon the condition
(amongst others) that I, the said William Brookes, my executors or adminis-
trators, by an instrument in writing under my, or their, or one of their hands
and seals, 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 William Brookes, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement thereof, that is to say):
The improvements relate to the application of the principle of statics
according to which the stress produced by inherent as well as extraneous weight
acts in the direction of the neutral axis of the iron tubes or cylinders com-
posing this arched system of construction combined with a contrivance for
controlling expansion and contraction.
Figure 1 is a geometrical elevation of the whole construction; Figure II. &
part of a normal section; Figure III. an elevation of a single arch piece
"vouissoir," with connection to right and left; Figure IV., part of plan and
elevation showing the expansion contrivace in centre of arch (Figures H..
and III. being on an enlarged scale), reference being likewise had to the letters
of reference marked thereon.
Te Invention consists in applying the round or polygonal hollow cylinder
or tube of the above description of material so as to bring solely its neutral
axis into combination, that is to say, the leading element of this construction
is the iron or cast-iron cylinder or tube, in which merely resistance to com-
pression through its length is brought into action without relying on its lateral
or cohesive strength. To make the advantage manifest the illustrative
comparisons Figures a, b, c, are subjoined.
In these three Figures W, W¹, W", denote loads of equal weight avoirdupois,
and C, C, C, round cylinders or polygonal tubes of the same lengths and
same diameters or sides; the length of any such cylinder or tube is, however,
never to surpass 12 times its diameter. It is obvious that the greatest possible
resistance such cylinder or tube is capable of is that which it opposes to 3
compression (Figure c). With these introductory remarks the description of
this new system of construction is proceeded with in a manner to give a clear
insight to those of the profession into the Invention.
Construction. The basis of this construction is the arch; in this arch all

page_text: that merely augments its inherent weight without contributing in any way to
its strength shall be eliminated. The statical lines respectively, the statical
surfaces i.e. the " extrados," and the "intrados" are constructed of one, of two,
or of any greater number of series of cylinders according to the length of the
span, and other exigencies of the particular cases, see Figure I. of accompanying
Drawing. The concentric arcs of the superior as well as of the inferior series
are composed of the above-named cylinders or tubes. The normal lines drawn
, to those concentric arcs represent iron or cast-iron plates P, P, Figures II.
and III., which in being fastened to the cylinders a, a, by screw bolts 8, 8, 8,
form the single arch piece ("voussoir "), Figure III., and the required number
of these arch pieces 'when fastened to each other shall form an arched truss."
The geometrical elevation of such a truss is represented by Figure 1; Figure
II. shows the connection of these trusses amongst each other.
Now it is evident that in this construction the stress produced by inherent'
weight as well as extraneous load will work in the direction of the neutral
axis of the tubes, and that this stress therefore will act upon the greatest
possible resistance of the metal under consideration.
The putting together of the cylinders and the framing the arch thereof is
performed either in the way shown by Figures II. and III. of the accompanying
Drawing, namely, they are cast in one piece and have a circular flange on
each end, wherewith they are fastened by means of screw bolts 8, 8, 8, to the
plates P, P, (which plates take always a direction normal to the inferior arc
of the structure) or else they are divided longitudinally into two halves and
provided with longitudinal flanges in the direction of the generatrix of the
cylinder, they are rivetted or screwed symetrically to a frame f, f, which frame"
owing to its size will rarely be made of one piece (see Figures V. and VI.)
Expansion and contraction.-But in order to make practical use of this
system of construction it becomes indispensable to combine it with a contrivance
to control expansion and contraction of the metal in a manner to keep the
interior construction as well as abutments in stone masonry sound and safe
from such effects; this is purposed to be done in the way following:-
The bridge or viaduct is constructed in two perfectly separate parts A, A,
almost in the manner of a pair of hinges (in this case, however, without the
connecting bolt), see Figure I., but particularly Figure IV. The semi-trusses
composing each half of the bridge terminate on their highest point alternately
in concave and convex ends, so as to fit exactly into each other. The extremities
of the bridge are completely rounded off, and fit exactly into the concave cast-
iron butts D, D, Figure I., fastened to the abutments. There will be, therefor,
a moveable rotation axis C, common to the two parts of the construction, and

page_text: two fixed rotation axes R, R, on each end of the bridge, Figure I. In this
manner the whole construction shall in its centre spontaneously rise when its
two perfectly rigid halves are expanding and retrocede to the proper point,
when they are contracting without injuring any part of the edifice.
Having thus described the Invention as, communicated to me, I would
have it understood that I do not claim any system of connecting, bracing, and
otherwise fastening together the trusses, either by themselves or amongst
each other, or any of them, with the parapet or railing, flooring, or other parts
of the structures; but what I claim is, the application of the principle of
statics, according to which the stress produced by inherent as well as ex-
traneous weight acts in the direction of the neutral axis of the iron tubes or
cylinders composing this arched system of construction, combined with a
contrivance for controlling expansion and contraction substantially as
explained.
In witness whereof, I, the said William Brookes, have hereunto set' my
hand and seal, this Twenty-eighth day of February, in the year of
our Lord One thousand eight hundred and sixty-six.
WILLIAM BROOKES. (L.8.)