IMPROVE- MENTS IN BRIDGES, GIRDERS, AND BEAMS
Year: 1848

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
DE BERGUE, of No. 9, Arthur Street West, in the City of London, Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Twelfth day of October, in the twelfth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Charles de Bergue, Her especial licence, full power, sole
privilege and authority, that I, the said Charles de Bergue, my exors;
adiñors, and assigns, and such others as I, the said Charles de Bergue, my
exors, admiors, 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 mentioned',
should and lawfully might make, use, exercise, and vend, within England;
Wales, and the Town of Berwick-upon-Tweed, my Invention of "IMPROVE-
MENTS IN BRIDGES, GIRDERS, AND BEAMS;" in which said Letters Patent
there is contained a proviso that I, the said Charles de Bergue, shall cause
a particular description of the nature of my said Invention, and in what
manner the same is to be performed, by an instrument in writing under my
hand and seal, to be enrolled in Her said Majesty's High Court of Chancery
within six calendar months next and immediately after the date of the said
in part recited Letters Patent, as in and by the same, reference being thereunto
bad, will more fully and at large appear.

page_text: This Invention for
Improvements in Driages, Girders, and Deams,
consists in a peculiar mode of constructing a compound tension, rod or bar
to be employed as a substitute for chains in suspension bridges; also a mode
or modes of constructing girders for bridges and beams, all of which will be
understood in and by the following description, reference being had to the
Drawing hereunto annexed, on which similar letters denote corresponding parts
in all the Figures.
DESCRIPTION OF DRAWINGS ON SHEET 1.
Figure 1 represents a side elevation of my improved girder for bridges.
Figure 2, a longitudinal vertical section. Figure 3 represents a side
elevation of a portion of Figure 1 drawn to a larger scale. Figure 4, a
transverse section taken through the line A, B, of Figure 3. a, a, a, Figures
1 and 2, represent a series of iron pipes. These pipes which are of different
diameters, are cast with a flange at each end, the end of each pipe being
accurately fitted, so that when bolted together they may form a pipe of a
curvilinear form, suitable for that part of the girder which is subject to
compression. The required curve to be given to this part of the girder
will vary according to circumstances. The end pipes, marked a', a', are cast
with a projecting rib b, b, provided with a flange b', which is bolted to
a solid casting c, c, supported by masonry of the bridge. d, d, the tension
rod or bar composed of steel or iron plates riveted together as shewn at
Figures 3, 4, and 5; each end of the tension bar d is firmly bolted or
riveted to the underside of the end castings b, b, and c, c, which are provided
with a lateral projecting flange of a breadth equal to the breadth of the
tension bar. The upper side of the tension bar is made to bear against the
lower end of the struts e, e. Each of these struts is composed of two or more
wrought-iron plates riveted together in the following manner:ff, is a plate
of iron equal in breadth at the upper end to the diameter of the flange of
the pipe. The upper end of this plate which is drilled with holes to cor-
respond with the holes in the flange, is placed and firmly bolted between the
flanges of the pipe as is clearly shewn at f, Figure 6, which represents a section
of the pipe taken through the line C, D, of Figures 3 and 4. e, e, is a plate
of iron forming portion of the strut, and is bent round the flanges so as to
cover and protect the joint of each pipe. This plate is firmly attached to

page_text: the plate by means of angle iron h, as shewn at Figures 4 and 5, which
latter Figure represents a transverse section of the strut taken through the
line E, F. i, i, represent diagonal stays or tie rods formed of flat bar iron.
The lower end of these tie rods is attached to the lower part of the strut by
means of rivets, as shewn at Figure 3, the upper end being attached to the
pipes a, a, by means of a bolt, as shewn at Figure 6. I prefer these bolts,
one of which is shewn separately at Figure 7, to be turned slightly eccentric
and squared up at the ends, as shewn at k, so that when the bolts have been
put in their place and the tie rods riveted at the lower end, sucli bolts may
be partly turned round by means of a spanner applied to the squared part k,
so as to bring the tie rods up to any required degree of tension; after which
the bolt and tie rod may be finally secured by means of a nut and washer.
I would remark with regard to Figures 1 and 2, that there is a slight difference
in the form of the two girders, the tension rod or lower part of the girder
in Figure 1 being shewn as straight, and in Figure 2 of a curvilinear form.
Figure 4 shews the plan of connecting the roadway with the girders. 0, 0,
represents a plate of iron strengthened at the upper and lower edge by means
of angle iron, and is similar to a wrought-iron girder. This plate, which
extends across the line from one girder to the other, is firmly rivited to the
plate f,f (see Figure 4), so as to form a rigid connection between the road-
way and the two girders. p represents a plate of iron strengthened in a
manner similar to that already described, and is intended to support the
longitudinal sleepers, the plate p being attached to the part o by angle iron,
as shewn.
I would remark, with regard to the tension rods or plates, that it may be
somewhat difficult, when steel is the material to be employed, to obtain plates
of sufficient breadth in one piece, in which case I propose to make them of
a series of plates of steel riveted together as shewn at Figures 8, 9, and 10,
Figure 8 being a plan, Figure 9 an end view, and Figure 10 an edge view.
In each of these views, d, d, represent a series of steel plates riveted together
so as to break joints with each other, the whole of the steel plates being
riveted upon a single wrought-iron plate d', equal in breadth to the series of
steel plates composing the tension bar. Note, I would remark that this
form of tension bar I intend more particularly for bridges of large span, when
strength with durability and lightness are required.
Another modification of my Invention is shewn at Figure 11, which
represents a side elevation of a girder constructed in a manner somewhat
similar to the one already described, with the exception that in place of using
iron tubes, as shewn at a, a, Figures 1 and 2, I employ beams of timber.

page_text: The top or compressing part of the girder is in this case composed of beams
of timber, 1, 1, as shewn in section at Figure 12. These pieces of timber,
which in this case are six in number, are arranged side by side, and jointed in
such manner that not more than one joint occurs in any section which can be
taken transversely through the girder, that is to say, the joints, which are
what is technically termed but-joints, are intended to be as far apart as possible.
The pieces of timber thus arranged are then firmly secured by means of three
wrought-iron plates, m, m³, m, and bolts as shewn. The form of these plates,
which are placed opposite to each "strut," will be seen on referring to
Figure 11. It will also be observed, that the centre plate m' (see Figure 12)
is sunk or let into the two middle beams, and the lower part of the plate
is made to fit into a slot cut in the upper part of the plate f¹; and
secured thereto by pieces of angle iron h¹, h¹. The vertical plate f¹ is also
firmly attached to the vertical outside plate g, g, by angle iron g', g'. The
plate for the centre part of the girder extends to the top, as shewn by dotted
lines (see Figure 11), and the ends of the several pieces of timber 1, 1, are
made to abut against each side of the centre plate.
Sheet 2.shews the application of my compound tension bar to a suspension
bridge as a substitute for the chain. The tension bar, when steel is to be
employed, is formed by two parallel series of steel plates firmly riveted to the
under side of a single but continuous wrought-iron plate, as shewn at Figure 1,
which represents an end view of the tension bar, full size, A, A, being the
parallel series of steel plates riveted to the under side of a wrought-iron plate
B by means of rivets C, C, in such manner as to break joints with each other,
the joints being what are technically termed but-joints. The wrought-iron
plate B is rendered a continuous plate by the application of short plates which
lap over the joints, and are riveted to the plate B, as shewn at 7, Figures 3
and 4. Figure 2 represents a side elevation of a portion of a suspension
bride, Figure 3 a.transverse section, and Figure 4 a plan view, shewing the
mode of attaching the suspension rods to the compound tension bar, which is
effected by means of a saddle or T piece made to pass through a slot in the
wrought-iron plate B. The upper end of the suspension rods, being made in
the form of a double joint, are attached to the lower end of the saddle piece
by means of a pin, which will be clearly understood.
Figures 13, 14, and 15 (Sheet 1) represent the mode of constructing beams
according to my Invention, the principal object being to gain great strength
with lightness. Figure 13 shews a side elevation and transverse section of a
beam constructed according to my Invention, and consists in the application
of a steel plate riveted to the under side of the beam, so as to form the

page_text: tension flange. The beam in this case is cast with a series of openings a, a,
and semicircular lateral projections b, b, at those places where the rivets for
attaching the steel plate to the beam pass through. Figure 14 shews
another modification of my improved beams, and consists in riveting an
angular plate of steel on each side of the lower part of the beam, so as to
form the tension flange. Figure 14 represents a flat plate of steel riveted to
the under side of the lower flange, for the purpose of increasing the strength
of the tension flange. This arrangement is intended to be applied more
particularly to beams that are too weak for the purpose intended, or such as
may require to be strengthened.
Having thus described the nature of my Invention, and the manner in
which the same is to be performed, I would have it understood that I do not
confine myself to the precise details herein-before described, so long as the
peculiar character of my Invention be retained, as the same may be varied in
many particulars without departing from my Invention. But that which I do
claim as my Invention is,―
First, the application of a tension bar, consisting of plates of steel, or.
wrought-iron, or wrought-iron and steel riveted together, to and for the
purposes herein-before described.
Secondly, I claim the general arrangement and combination of parts herein-
before described, when constructing bridges, girders, and beams.
In witness whereof, I, the said Charles de Bergue, have hereunto set
my hand and seal, this Twelfth day of April, in the year of our Lord
One thousand eight hundred and forty-nine.