IMPROVEMENTS IN SUSPENSION BRIDGES
Year: 1857

page_text: LETTERS PATENT to Rowland Mason 'Ordish, of Saint Mark's Crescent,
Régents Park; in the County of Middlesex, for the Invention of
"IMPROVEMENTS IN SUSPENSION BRIDGES."
Sealed the 1st May 1857, and dated the 7th March 1857..
PROVISIONAL SPECIFICATION left by the said Rowland Mason Ordish
at the Office of the Commissioners of Patents, with his Petition, on the
7th March 1857.
I, ROWLAND MASON ORDISH, of Saint Mark's Crescent, Regent's Park,
in the County of Middlesex, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN SUSPENSION BRIDGES," to be as follows:-
The ordinary suspension bridges are deficient in rigidity as the chains hang
in curves, and each variation in the position of a passing-load produces an.
alteration in the curve of the chain, and in the form of the platform supported
by.it..
I-construct rigid suspension bridges by.supporting each of a series of points
by means of inclined straight chains or ties from one or both piers, which
chains or ties are sustained in a straight position by means of rods or struts
connected or not to the platform, and to curved or bent chains also hung from
the piers.
These points are thus rigidly.supported by the straight chains or ties, and
they carry the platform, which is made sufficiently strong to support itself and
the load between the aforesaid points. The platform itself may also be made
to act-as a strut or tie. The land ties or chains are also made straight, and
supported in a similar manner. The chains or ties may be made of links
jointed together; or they may be wire ropes or rods or plates, welded or

page_text: rivetted, or otherwise connected together; or they may be made in the form of
box girders, or otherwise, as may be most convenient, as they are not required
to be flexible liko the chains of ordinary suspension bridges. By these means
rigid suspension bridges are produced, which aro adapted for railway traffic,
and other purposes.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Rowland Mason Ordish in the Great Seal Patent Office on
the 1st September 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROWLAND
MASON ORDISH, of Saint Mark's Crescent, Regents Park, in the County of
Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by IIer Letters
Patent, bearing date the Seventh day of March, in the year of our Lord
One thousand eight hundred and fifty-seven, in the twentieth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Rowland Mason Ordish, Her special license that I, the said Rowland
Mason Ordish, iny executors, administrators, and assigns, or such others as
I, the said Rowland Mason Ordish, 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 Iuvention for
"IMPROVEMENTS IN SUSPENSION BRIDGES," upon the condition (amongst others)
that I, the said Rowland Mason Ordish, my exccutors or administrators,
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 Rowland Mason Ordish, 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, reference being had to the accompanying Draw-
ings, and to the figures and letters marked thereon, that is to say :-
The ordinary suspension bridges are deficient in rigidity as the chains hang

page_text: in curves, and each variation in the position of a passing load produces an
alteration in the curve of the chain, and in the form of the platform supported
by it.
I construct rigid suspension bridges by supporting each of a series of points
by means of inclined straight chains or ties from one or both piers, which
chains or ties are sustained in a straight position by means of rods or struts
connected or not to the platform, and to curved or bent chains also hung from
the piers. These points are thus rigidly supported by the straight chains or
ties, and they carry the platform, which is made sufficiently strong to support
itself and the load between the aforesaid points. The platform itself may
also be made to act as a strut or tie. The land ties or chains are also made
straight, and supported in a similar manner. The chains or ties may be made
of links jointed together, or they may be wire ropes or rods or plates, welded
or rivetted, or otherwise connected together, or they may be made in the form
of box girders, or otherwise, as may be most convenient, as they are not
required to be flexible like the chains of ordinary suspension bridges. By
these means rigid suspension bridges are produced, which are adapted for
railway traffic, and other purposes.
Figure 1 is an elevation or diagram, shewing the arrangement of chains in
one form of bridge, constructed according to my Invention. A and B are the
piers; C is the platform, which rests on the piers at the two ends, and is
supported at four intermediate points D, E, F, G, by the inclined straight bars
or chains H', H, H³, H*, and I', I, I, I, which are secured to cradles or
saddles on the piers A, B, which saddles are retained by the inclined straight
land ties, bars, or chains J, K. These inclined straight chains H, H, HI³, II*,
11, 1, 1, 1, and J, K, are supported in straight lines, and prevented from
sagging or hanging in curves by means of the curved chains L, M, N, to
which they are suspended by vertical rods a, a, a, a. The platform is mado
rigid, and sufficiently strong to carry the load between the points at which it
is supported by the inclined straight chains.
The effect of this arrangement is that the platform and the load upon it
are carried entirely by the inclined straight chains H', H, H, H, I, I, 1.1*,
and the piers A, B, while the weight of those chains themselves is carried by
the curved chain M. The chains H', H, H, H, I, I, I, 1, being straight,
are not altered in' form by the passage of a load over the bridge. The load
on the curved chain M being constant and unaffected by the load on the
platform, that chain also remains unaltered in form. The whole bridge is thus
nde rigid, and remains unaltered in form during the passage of a load, except-
ing of course the deflection or extension due to the elasticity of the material..

page_text: The inclined straight.chains.may be made of iron bars or links, extending
from one suspension rod a.to.another, or extending over the:intervals.of.several
suspension rods, or they may be welded together, or otherwise made in single
lengths from each point. in the platform to the points on the piers or towers,
as. may be found convenient. Or, they may be made of wrought-iron plates,
rivetted together into the form of a box, so as to enable them to support
themselves when the suspension rods a, a, are placed at.a considerable distance
apart. On the other hand, wire ropes may be employed for these inclined
straight chains, provided that the wire rope is sufficiently stiff, and the
suspension rods are placed so near together that the wire rope may not
sag: down or curve itself to any injurious extent between the points of
suspension.
Figure 2 is a diagram or side view.of.another :bridge constructed according
to my Invention, with a slightly different arrangement of the chains. In this
.case the,platform is supported at nine intermediate points D', D³, D³, D', D³,
D', D', D, D, by the inclined straight chains H', H³, H³, H*, H³, 1, 1, 1
1, 1, and their junctions or intersections. Thus, the point D' is sustained
by H' and '; D' is sustained by II and I'; D³ is sustained by a vertic:
rod from the intersection of Hand 1'; D'is sustained by a rod from the
intersection of II and 1', and also directly by H and 1. The central point:D'
is sustained by a rod from the intersections of H and I', and of H and 1
The other points are suspended in a similar manner. The inclined straight
chains are supported as before by vertical rods a, a, from the curved chain M.
The straight land ties J, J, K, K, are similarly supported by the curved
chains L, N.
On the right-hand sido of the Drawing is shewn a mode of supporting the
platform C beyond the pier. His an inclined straight chain, and 1º is a
horizontal straight chain, fixed to the abutment. Theso chains support the
point D, and are themselves kept straight by being suspended to the curved
chain N.
Figure 3 is an elevation or diagram, shewing an arrangement of chains
adapted for a bridge of several spans. When one span of a suspension bridge
is loaded while the other spans are unloaded, the weight or strain upon the
loaded chains has a tendency to drag the saddles over the tops of the towers, or
to drag over the towers themselves if the chains are fixed to them. This result
is prevented by the arrangement shewn in Figure 3. P¹, P, P³, P, P, P
may be called the main inclined straight chains to various points, in which
are connected the inclined straight chains H, H, H, H, H, H, H', H, I,
and I, 1, 1, 1, 1, 1, 1, 1, 1, which support the various points in the

page_text: platform. All these inclined chains are supported at intervals by the curved
-chains M, M, M. The land ties or chains J, K, are in like manner sup-
ported by the curved chains L, N. The junctions of the chains Ps and P³,
and of the chains P' and P³, are tied down to the piers A, A, by long rods
or bolts passing down into the inasonry, and shewn by dotted lines.
If the central span only of this bridge be loaded, the piers or the saddles
upon them will be sustained by the two inclined chains P1, Pe, which are
moored.or fixed to the land on each sille. If the left hand span.only be loaded
the saddles will be sustained or retained by the land ties 3,anil by the inclined
chains P, P, and the land ties K. "The strain on the chains P, P³, 'his a
tendency to lift the tower Q and; the pier A on which it stands; the weight
of these parts, including the weight resting upon them, must be sufficient to
resist the upward strain on the inclined chains. In like manner a load on the
right hand span is sustained by the land ties K, and the inclined chains P³, P",
and land ties J,-and resistod by the weight of the tower Qand pier A. The
vertical bolts in the piers which hold down the chains P, P, P, and P³, may
be secured at their lower ends and allowed to move a little from side to side
at the upper part, so as to allow for the slight motion due to the elasticity of
the material, and to the expansion and contraction occasioned by changes
of temperature. The chains, which are conducted to the tops of the towers,
may be attached to or carried over saddles resting on rollers on the towers, or
supported or suspended by means of vertical links to points on the towers; or
the towers themselves may be constructed of iron or other suitable material,
and made to turn or rock upon suitable supports on the piers, so as to allow
for the elasticity and expansion and contraction of the chains. In an ordinary
suspension bridge it is necessary not only to allow for the motion due to
elasticity and expansion and contraction, but also for that caused by the curved
chains being dragged over the towers from the unloaded to the loaded parts of
the bridge.
Figure 4 is an elevation or diagram shewing an arrangement of chains
adaptod for a bridge having an opening in the centre for the passage of ships
or other vessels. R is a central tower standing on two piers S, S'; T is a
portion of the platform between the piers S, S¹, which is capable of being
raised and lowered to allow of the passage of vessels. P¹, P², P³, P², P³, Pº,
P', P, are the main inclined- straight chains. The other parts are indicated
by similar letters to those on the last Figure. When the smaller left hand
span is alone loaded, the strain on the chains is sustained by the land tie J
and the chain P. The strain on the chain P is resisted by the chains P³, I²,
13, 1, and the weight of the platform of the larger span suspended to them,

page_text: and also partly by the pier S. The strain, conducted by the chains P³, I, I, I,
to the saddle on the central tower R, is sustained by the chains P, P', and
the land tie K, and tho weight of the tower Q and pier A'. When the left
hand larger span is alone loaded, the strain on the chains is sustained by the
chain P¹, and the chains P, P', and land tie K, and the weight of the tower
Q' and pier A'.
It is not necessary that the curved chains should be entirely above the
inclined straight chains, as shewn in the Drawings, but they may be partly
below them. The rods a, a, are then made sufficiently stiff for their upper
ends to serve as struts to carry the inclined straight chains above the curved
chain, while their lower ends serve to suspend the inclined straight chains
below the curved chain.
The modes of connecting the chains or bars and constructing the platform
admit of variation. In Sheets II. and III. of the accompanying Drawings,
some of these details are shown on a larger scale. Figure 5, Sheet II., is a
side view or elevation of a portion of the platform and chains of the bridge,
shewn in Figure 3, Sheet I. Figure 6 is a plan of the same; Figure 7 is a
transverse section; and Figuro 8 is a longitudinal section of the same. M' is
the curved chain, and P, P, and H³ are some of the inclined straight chains
which are suspended by the rods a, a, to the curved chain M'. The chains or
bars are united by short links or joint plates c, d, and c, f. One or more of
these plates d and fare made deeper than the others to receive the rods or
bars U, U, which carry the cross girders V. On these cross girders rest the
continuous longitudinal wrought-iron girders W, which support cross girders
X, X, X, carrying the longitudinal bearers Y and the rails Z. The spaces
between the bearers Y may be filled with bearers g and planking & for greater
security. The girders W also form a rail or parapet; on each side of the
bridge i, i, are diagonal ties for the purpose of giving lateral stiffness to the
platform.
Figure 9, Sheet III., is an enlarged side view of portions of the chain M
and P in Figure 5. Figuro 10 is a transverse section of the same. a, a, are
the vertical rods which support the straight chains by means of plates a'
inserted at the junctions of the bars of the chaius. a' is a socket with right
and left-handed screws into which the rods a are screwed; by turning these
sockets the inclined chains can be adjusted until they are straight or nearly
so. The rods a, a, may also have joints to allow of the chains moving or
swinging in a transverse direction without bending the rods.
Figure 11 is an enlarged elevation or side view of the joint c, d, in Figure 5,
and a portion of the platform suspended to it. The various parts are similarly

page_text: lettered to those shown in Figures 5, 6, 7, and 8. Figure 13 is an elevation
or side view of one of the saddles on the central tower of the bridge shewn in
Figure 4, Sheet I. Figure 14 is a vertical transverse section of the same;
Figure 15 is an end view of the saddle, shewing sections of the inclined
straight chains. jis the saddle which may be of cast iron supported on
rollers k, k, k, resting on a flat plate placed on the tower of the bridge.
m, n, o, are a series of wrought-iron plates to which are bolted the inclined
straight chains II, H, H; P, and also the chains or bars p, p, whose opposite
ends are connected to a similar series of plates on a saddle at the other side
of the tower. The saddle j has a stop or projection i formed or fixed upon it,
which comes in contact with the plates o, and prevents the saddle from being
forced towards the centre of the tower by the strain upon the inclined chains.
The saddle is capable of moving a little on the rollers & so as to allow for the
expansion or contraction due to changes of temperature or the elasticity of
the material. It will be obvious that the details of the saddles and con-
nections and the construction of the platform admit of variation. As already
berein-before mentioned, tho construction of the chains may be varied, and
they may consist of wire ropes, if preferred. The so-called inclined straight
chains may be slightly curved without materially affecting the rigidity of the
structure, but this curvature should never exceed that which would occur in
them, if they were unsupported by the curved chains, and sustaining the
maximum loads; and I prefer to make them very nearly or quite straight.
The so-called vertical rods may also be inclined at various angles, if desired.
When the whole length of one of these bridges is loaded, the inclined
straight chains will be slightly extended by the tension upon them, and the
whole platform and system of chains between the piers will be slightly deflected.
The consequence will be that if the curved chains are anchored in the ordinary
manner, some strain in addition to that produced by the weight of the inclined
straight chains (which is constantly borne by the curved chains) will be pro-
duced in them. This increase of strain may, however, be prevented or relieved
by carrying the curved chains over saddles in the abutments, and mooring
them to heavy weights resting on the ground instead of to fixed points. When
the extra strain comes on the curved chains, these weights will rise a little
and allow the chains to deflect to the required amount, and they will return
to their seats or resting places as soon as the load has passed off the bridge.
When only a portion of the bridge is loaded, the curved chains will accom-
nodate themselves sufficiently by a slight variation in their curvature. A
portion or the whole of the weight of the platform may be suspended by the
curved chains, if desired, by connecting the vertical rods a to the platform, or

page_text: by, independent:curved. chains-supporting the permanent load of the platform!
only, and, allowing the inclined: straight chains. to receive. the variable strain.
produced. by the. load. passing, over, the bridge. In this case it will be the
more: necessary to employ weights for mooring" the curved. chains, or other
means,,to, relieve the curved chains: from the strain which would be brought-5
upon them by the deflection due to the extension of the straight chains:
Having now.described the nature of the said.Invention, and in what manner.
the same. is to be performed, I wish it to be understood that what I'claim. is,
constructing; suspension bridges, in such manner. that the weight of the load,,
or. of: the load and the platform; is: sustained by inclined straight or nearly: 1
straight chains, extending from. the towers or piers and meeting or intersecting
each other, and: which are themselves! sustained or suspended in the.required..
form by curved chains, as-herein-before described.
In: witness whereof,, I,, the said Rowland Mason Ordish, have hereunto.
set my hand and: seal, this Thirty-first day of. August in the year of 1
our Lord.One.thousand eight.hundred and fifty-seven..
Witness;
ROWLAND MASON: ORDISH (L:s):
EDWARD INGRAM. WOODHEAD; -
8, Denbigh Street, Pimlico, London!'