Year: 1886

page_text: Date of Application, 14th Apr., 1886.
Complete Left, 9th Dec., 1886.
Complete Accepted, 11th Feb., 1887.
improveme
I, WILLIAM PHILLIPS THOMPSON Fel. Inst. P.A. of the Agency for Foreign Patent
Solicitors, 6 Lord Street, Liverpool in the County of Lancaster and 323 High Holborn,
in the County of Middlesex Civil Engineer, do hereby declare the nature of this
invention to be as follows:-
This. invention relates to bridges in which there are compressive and tension
members, but in place of one tension member, or one chord, there are several chords
preferably formed of eye-bars one above the other and parallel or nearly so.
The principal of two or more tie bars, one taking the strain at the upper part, the
others at lower points, can be used for roofs, which are in fact bridges connecting the
two opposite walls of a building, but except in very large spans must have but a
limited application for such purposes.
In composite bridges having both straight and curved compression girders one
tie bar could take the strain of one of these and another the strain of the other.
WM. P. THOMPSON & Co.,
Agents for the Applicant.

page_text: Improvements in Bridges and similar Structures.
A communication from JOSEPH TOMLINSON, of Ely, Linn County, State of Iowa,
United States of America.]
I, WILLIAM PHILLIPS THOMPSON, Fel. Inst. P.A. of the Agency for Foreign Patent
Solicitors, 6 Lord Street, Liverpool, in the County of Lancaster, and 323 High Holborn,
in the County of Middlesex Civil Engineer, do hereby declare the nature of this
invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
This invention relates to bridges and like siructures, in which chords formed of
eye-bars connected by pins are employed, and the invention consists in a compound
chord, formed of two or more such single chords placed one above another; in providing
compound posts each main member carrying an independent set of suspenders, and
each system of suspenders having an independent anchorage or attachment, in a novel
arrangement of the connections between the main truss or trusses, and the intermediate
truss, by which expansion and contraction are provided for and in various other
features and details hereinafter pointed out and explained.
In the accompanying drawings Figure 1 is a side elevation of a portion of a bridge
constructed in accordance with my invention.
Figure 2 is a top plan of the same.
Figure 3 an enlarged view of the upper and central portion of figure one showing
more plainly the details of construction.
Figure 4a section on the line
of Figure 3.
Figure 5 a section on the line y-y of Figure 3.
Figure 6 a plan view of the chords and saddles.
Figure 7 a side elevation of the shore end of the truss.
Figure 8 a view illustrating the connection between the main trusses and the inter-
mediate truss.
The primary object of this invention is to secure the efficient action of a greater
number of eye bars in the chords and suspenders of long span bridges than has been
practicable under any construction hitherto known, and in the attainment of this end
in the manner hereinafter to be described a more compact and effective arrangement
of the chords than heretofore is also secured.
In prior constructions wherein the chords have been formed of eye bars and pin
connections, the only manner in which adequate strength could be attained has been
by making the eyebars wide and heavy, or by building up the chords of many eyebars
placed side by side and consequently producing a chord of very great width, requiring
wide saddles and bearings and otherwise adding to the difficulties of construction, and
impairing the appearance of the finished work.
These difficulties and objections are obviated by making a compound chord, composed
of pin-jointed eye-bar chords, arranged in series or tiers, one tier above another.
This will be better understood upon referring to the drawings in which A. B.
indicate piers, the latter carrying pierposts or columns c which support the chords D.
The posts or columns e each consists of four posts, a, b, a, b, arranged in pairs, the
C

page_text: two posts of each pair connected by diagonal bars or latticing, e, and the two compound
posts thus formed being connected by ties, d, which also form spacing pieces.
By this construction a very strong tower or support is produced and one which
affords a wide footing and wide seats on bearing surfaces for the saddle, thus ensuring
the distribution of the superposed weight over a large surface or area.
As shown in figure 3 the outer columns b, b, are made somewhat shorter than the
intermediate columns a, a, in order to produce the necessary curvature or arching form
at the top of the compound post or column for the saddle, E, to rest upon.
As best shown in figures 1 and 3, the chords, D, consist each of a series of
eve bars arranged side by side in groups the ends of the bars in one group extending
between those of the adjoining groups, and joined thereto by pins, passing through the
eyes of the overlapping ends, as usual, and two or more of such single chords are
placed one above another as in figure 3, to produce the compound chord D.
The different tiers of single chords extend from the saddle on the pier posts, to
different distances, as shown in figure 1, the upper chord extending to the ends of the
main truss; the second one to points nearer the pier posts, and the lower one to points
still nearer the pier posts, thus proportioning the strength of the chord as a whole, to the
load or stress, it has to carry at different points in its length.
The number of tiers or single chords may of course he varied as required, three
being represented in the drawing.
From each post a, b, a, b, independent sets of suspenders, F run downward at proper
angles, to support the lower chord G, and the compound posts H, H.
Each compound post or column H consists of two posts or columns a, b, latticed or
connected by short diagonal braces or bars.
From the top of each single main member of the compound post or column a set of
suspension rods F runs downwards to the lower chord G at the foot of the next post or
column in the same system of bracing, and so on to the ends of the main truss, on each
side of the pier posts.
The pier
has built in it a number of anchorages J, sufficiently far apart to
correspond with each set of suspenders, at their connections with the shore end of
the lower cord of the main trusses, as best shown in Figure 7.
As shown in figure 3 the saddle E, is composed of eye bars, g, h, i, extending over
and formed to fit firmly on the flat tops of the separate members b, a, a, b of the
pier posts. They are firmly connected together and to the suspenders by the pins j.
The edges of the ends of each tier of eye-bars are formed to rest firmly on each
other thus forming webs to sustain and distribute the stresses transfered to them from
the eye-bar chords and suspenders, over the top surfaces of the pier posts leaving the
spaces usually required for the vertical extension of the posts to be occupied by
eye-hars.
By thus arranging the tensile members over the pier posts, their action is more
direct and efficient than it could be if separated, and so spread at greater distances
apart.
From the eye-bars g and i, longer eyebars extend to connect with short eye-bars f
which connect the upper ends of the two members of the compound posts H, and also
form members of the chord D. By this arrangement, and, by passing the connecting
pins j, through the vertical extensions k, of the members of each compound post or
column H, as well as through the eye-bars, each member of each compound post is
made to transmit the weight it has to carry, independently of the other or others, and
caused to adapt and adjust itself to the load or stress it is required to bear.
As illustrated in Figure 2 the saddle E, of each of the main trusses are spread apart
or separated more widely than the bodies of the chords, which is for the purpose of
giving lateral strength and stability to the structure. This separation is maintained
by cross girders or stretchers K, extending across the bridge from saddle to saddle as
indicated in figures 3 and 6.
In order to give the proper directions to the chords D from the saddles to the ends
of the main trusses, the eye-bars h, of the middle section of each saddle are bowed or
curved as illustrated in Figure 6, and to prevent collapsing under strain or tension,

page_text: h
filling pieces or blocks, m, are interposed between the respective eye-bars / as shown
in said figure.
The pier posts and main trusses at both ends of the bridge being thus constructed,
an intermediate truss L is provided to fill the space between the ends of said main
trusses. This intermediate truss, may be of any approved construction, single or
double, or partly double and partly single intersection.
The truss Lis connected to the main trusses, in the manner illustrated in Figure 8 to
provide compensation for expansion and contraction, without the use of oblique posts
such as have been necessary under former constructions.
As shown in said Figure and in Figure 1 the main truss terminates with the
suspenders F and lower chord G, the latter projecting beyond the last compression
member or post H. of the truss, and the suspenders running down to the outer end as
shown.
The central truss L is formed with its upper chord longer than the lower chord and
the suspenders M, at each end run upward to the outer extremity of the upper chord at
about the same angle as the suspenders F, or substantially so, thus giving the appear-
ance of a continuous and uniform design.
The extremities of the two trusses that is to say the outer end of the lower chord
of the main truss, and the outer end of the top chord of the middle truss are connected
by vertical posts N, connected to each with pin connections and constituting movable
compression members.
It will thus be seen that instead of suspending the middle truss by vertical eyebars
from the upper chords of the main truss as heretofore the middle truss is supported
from the lower chords of the main truss. Under this arrangement it is of course
necessary to employ slotted filling struts to control or regulate the extent of move-
ment of the end posts N.
It will of course he understood that the curvature of the saddle is not an essential
feature of this construction, and in some structures may not be desirable and in structures
of moderate dimensions the saddle can be formed with one length of eye-bars.
Some features herein set forth are of course applicable to other structures.
Having now particularly described and ascertained the nature of the said invention,
and in what manner the same is to be performed, as communicated to me by my foreign
correspondent I declare that what I claim is :
1. In a bridge or like structure, a chord composed of two or more substantially
parallel eye-bar chords placed one above another, and connected at the ends by pins
passing through the web extensions of the compound posts, whereby the tension on
the upper tiers of the compound chords is not affected by the tension of the lower
parallel tiers as set forth.
2. In a bridge or like structure, a flexible chord, composed of two or more eye-bar
chords placed one above another and connected together at the ends of the eye-bars by
pins passing through web extensions of the supporting posts, and pinned to a saddle
composed of plates or eye-bars pinned together horizontally and arranged in tiers one
upon another, and upon the top of the pier-posts as set forth.
3. In combination with a compound column or pier post, consisting of posts, b, a, a, b,
the saddle E. composed of eye-bars, g, h, i, connected at their ends by pins, substantially
as set forth.
4. In a bridge or like structure, the combination of a compound or double post and
independent sets of suspenders running from each main member of the compound post.
to the lower chord and vertical member to be sustained.
5. In a bridge or like structure, the combination of a series of sets of eye-bar
suspenders and a separate anchorage for each series of sets of eye-bar suspenders,
substantially as explained.
6. In a bridge, the combination of main trusses, an intermediate truss and vertical
posts connecting the lower chords of the main trusses, and the upper chord of the
intermediate truss, and adapted to move with the chords to which they are connected
as the longitudinal members of the bridge expand or contract.

page_text: 7. In a bridge, the combination of pier posts, saddles composed of eye-bars or plates,
resting upon said posts, and arranged in tiers, one tier above another; flexible
compound chords composed of two or more eye bar chords placed one above another,
connected by links substantially perpendicular thereto, and attached to the saddles, a
platform, and suspenders connecting the platform and the chords all substantially as
described and shown.
8. In a bridge the combination of chords composed of two or more single eye-bar
chords placed one above another, compression lower chords, compound posts extending
from said lower chords to the eye-bar chords, and independent set of suspenders,
extending from the top of each main member of the compound posts to the lower chords
substantially as set forth.
9. The herein described bridge consisting of suitable piers, columns or posts mounted
upon the piers, compound eye-bar chords, extending from the pier posts in the
direction of the bridge, compression chords extending from the pier in the same
direction, compound compression posts or members extending from compression chords
to the eye-bar chords, and suspenders extending from each main member of the
compound posts to the chords, substantially as shown and described.
10. In combination with piers A, B and posts C, compound eye-bar chords D,
saddles composed of eye-bars or plates, suspenders F lower chords, G and compound
posts H all combined and arranged substantially as set forth.
11. In a bridge such as described and shown, the combination of lower chords G,
compound posts H. having vertical extentions k, and chords C, composed of eye-bar
chords joined together and connected with the vertical extensions by pins j.
12. In a bridge or like structure a saddle composed of eye-bars or plates pinned
together in sectional lengths the bars or plates of the middle section curved inwardly,
spaced apart and connected to the end sections by pins at right angles to the convergeni.
chords, and arranged in tiers to bear one upon another on the top of the pier posts, as
set forth.
WM. P. THOMPSON & Co.,
Agents for the Applicant.