and Apparatus for Raising Girders, Trusses, and the like Members of Lofty Structures.
Year: 1888

page_text: шргоvcu шестой of and Apparatus for Raising Girders, Trusses,
and the like Members of Lofty Structures.
I, GEORGE ANDERSON, M Inst C.E, of Madras, in the Empire of India, District
Engineer to the District Board of Malabar, do hereby declare the nature of this
invention to be as follows
-
My invention relates to raising girders, trusses, and the like members of
lofty structures, such as bridges, to the construction of which it is particularly
applicable
According to the method of bridge-building in use at the present time, it is the
practice to construct expensive scaffolding, or to raise the girders and trusses by
hydraulic power applied beneath them.
For iaising girders in building warehouses and the like, derricks overhanging the
scaffold have generally been employed.
Now according to my present invention I dispeuse altogether with the ordinary
scaffolding
Upon the tops of the bridge-piers, for instance, I construct a vertical superstructure
of a suitable height, from the top of which project, at right angles with the line of
the bridge, two cantilevers, one on each side.
For the actual lifting, I provide jacks and lifting rods of any suitable or well-known
construction.
The girders are floated out to, or put together at, the foot of the piers, one above
and the other below stream
To each end of the girder I fix two bars so as to form with the end thereof a
triangle During the lift, the upper of the said two bars will be in compression and
the lower in tension, their junction being the point to which the lifting rod is
connected.
The lengths of the said rods is so adjusted that the strain during the lift shall be
vertical, and their junction safely above the centre of gravity in the girder.

page_text: As both guders will be lifted at the same time, there will be no lateral strain upon
the superstructure
The above mentioned two bars may be dispensed with when the girders have
square ends
Suitable traversing apparatus is emploved
PHILLIPS & LEIGH,
Agents for the Applicant.
Improved Method of and Apparatus for Raising Girders, Trusses,
and the like Members of Lofty Structures.
I, GEORGE ANDERSON, M Inst CE, late of Madras, but now of Calicut, Malabar,
in the Empe of India, District Engineer to the District Board of Malabar, 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:
My invention relates to raising and placing girders, trusses, and similar members
of lofty structures, and consists in an improved method of, and apparatus for,
effecting such constructional work. It is particularly applicable to the construction
of lofty budges, and for this reason I have selected its employment in the construction
of a lofty bridge across the bed of a stream of variable width as a suitable subject
for illustration.
According to the method of bridge-building in general use at the present time, it
is the practice to construct expensive false works or scaffolding, or to raise the
girders or trusses by hydraulic power applied from beneath For raising girders
in warehouse and similar building, derricks overhanging the scaffolding have
generally been employed
In order that this invention and the means by which the same is to be carried into
practical effect, may be thoroughly understood, I will now describe them in detail,
referring in so doing to the accompanying drawings which are to be taken as part of
this specification and read therewith; and in which
Fig. 1 is a general elevation of the land-piers of a bridge, shewing three stages of
girder-raising as the process is conducted according to my invention.
The left hand girder is waiting to have the lifting chains attached to it: the
centre girder has been lifted about half way, whule the one on the right hand has
not only been lifted, but has been traversed inwards, and placed on its permanent seat
upon the pier-tops.

page_text: Fig 2 is a transverse elevation of a mid-stream pier, its superstructure, cantilevers
and lifting and traversing apparatus, shewing a pair of girders-one for the
up-stream, and the other for the down-stream side of one bay-in the process of
being raised
Fig 3 is a detail side elevation, i.e, looking across the stream, of the cantilevers,
and lifting and traversing apparatus.
Fig 4 is a detail front elevation, ie, looking up or down stream, of a cantilever
and lifting and traversing apparatus
Fig 5 is a plan corresponding therewith.
A, A are the piers; and B. B, the girders.
C, C are removable super structures of proper strength and height erected upon the
pier-tops
D, D are transverse cantilevers upon the top of a superstructure having a
tramway d land longitudinally thereupon
The projection of a cantilever is according to the diameter of the base of a pier,
so that when the traverser is run out, it will bring the axis of the lifting jack vertically
over the point of attachment of the lifting chain to the girder
E, E are platform-traversers adapted to be moved along the tramways d, in either
direction, independently of each other Their area is sufficiently large to afford safe
working space for the lifting and traversing gang
F, F are beams laid parallel with each other across the platform E, for the purpose
of furnishing bearings at a convenient level above the platform for G, the retaining
pin, to rest upon The platform itself is also used for the purpose of supporting a
second retaining pin G¹.
H, H are lifting jacks or hoisting apparatus of any convenient type standing upon
the platform-traversers E, E.
I, I are beams carried by the lifting jacks, and adapted to receive the full weight of
the girders to be raised, and of
K, the lifting chain, through
L, the lifting pin
The lifting chain may be of any convenient construction The one which I have
illustrated in the drawings is the one which I consider to be as well adapted as any
other to the purpose of my invention
The chain consists of a number of metal
links connected by pins or boits 1. Holes are made in the chain at regular
intervals to receive the pins G, G' and L
The method of attaching the lifting chains to the girder-ends depends upon the
shape of the latter.
It they are square, or in other words, if the extreme ends of the girder, when the
latter les ready for being lifted come vertically under the lifting jack, then the chains
are attached to the top corners of the girder, when not only will the pull be straight,
but the points of attachment of the lifting chains to the girder will be safely above
the centre of gravity in the girder. But it not unfrequently happens that the girder-
end does not present any point adapted for use as a point of attachment, inasmuch as
none of the end may come vertically under the lifting jacks, without being beneath,
or at any rate too near, the centre of gravity.
Now my invention provides in the manner next described for the lifting chains
working in a vertical line, and the points of attachment being sately above the centre
of gravity in the girder, irrespective of either the length of the latter, or of the
shape of its ends
For the sake of illustration I have shewn the girder ends b as sloped.
It is self-evident that the lifting chains would not pull vertically if they were
attached to the top corners 6'; and that, if they were attached to the bottom
corners, the point of attachment would be beneath the centre of gravity in the
girder It therefore becomes necessary to establish points of attachment e vertically
under the jacks and above the said centre of gravity. This I accomplish by the
use of tension and compression bars, or pairs of bars, M and N, at each end of
the girder, and springing respectively from the top and bottom corners of the girder,

page_text: the lift.
e,
or from near those points. They unite to form the points of attachment which
junction will bring the former into compression, and the latter into tension during
The bar, or bars, N are long enough to throw the point of attachment safely above
the centre of gravity, and the bar, or bars, M are long enough to throw the point
of attachment far enough out from the girder to bring the said point vertically under
the jack.
If a square ended girder is too short to bring its top corners vertically under the
lifting Jacks, then I provide proper points of attachment by means of bais M and N
as above described and this said tension-and-compression-bar-device may be applied to
any shaped girder which does not contain within itself points of attachment at once
vertically under the Jacks and safely above the centre of gravity in the girder
I will now explain the way in which my invention is worked, by way of describing
the several stages of raising and placing a pair of bridge-girders
1. The girders completely erected and ready for lifting are brought down alongside
the piers upon the top of which they are to be placed, or they may be erected in situ
alongside the said piers upon a suitable platform, natural or artificial
The left hand
girder in Fig 1 destined for the first above water span is shown as having been rolled
down onto a staging O consti ucted across the stream
2 By the time that the girders are ready for the span the two superstructures C
for the piers of that bay, with the cantilevers, platformi traversers, jacks, and framing,
should also be ready
3. The lifting chains K are carefully put together (preferably in right lines upon
the ground, so that all risk of their doubling or kicking whilst the lift is on shall be
obviated), and lifted into working position The pins L, G, and G₁ are then passed
through the respective chains K. the latter attached to the girder ends (or to the
tension and compression bars if they are required), and the beams F and I
adjusted.
4. The Jacks are simultaneously put into operation, and the girders lifted as far as
the lift of the jacks permits As the retaining pins G and Gaie carried up with
the lifting chains, they are packed up by means of union wedges, or other suitable
packing, so that they shall take the respective loads of the chains and girders when-
ever the jacks stop, and transfer them direct to the cantilevers without shock, and so
far preventing risk of accident from the snapping of the lifting pins or collapso of
the Jacks When the Jacks lave got to the end of their respective lifts
they are run down, and the hifting pins fitted into lower holes in the respective
chains, ready for a second lift, and so on, until the girder has been raised to the
required height.
5 The suspended girders are next traversed inwards, by operating the respective
traversers accordingly, and laid upon their respective seats.
For general work when there are several spans to he bridged, three sets of super-
structures, cantilevers, traversers, Jacks, beams, chains, pins, and tension and
compression bars, should be provided, so that when the first pair of girders has
been lifted and placed, the tackles for the next pair (e on the second and third
piers) will be ready for lifting and placing the second pair of girders, while the
tackle from the first pier is being moved therefrom and erected upon the fourth
pier, so as to be ready for lifting the thud pair of girders by the time that the
tackle on the third pier shall be disengaged from the second pan A more
extensive supply of tackle than that enumerated above may, of course, be provided,
if it be desirable to lose no time at all in shifting from one pier to another
I wish it to be distinctly understood that my invention is not confined to the
precise details as the same are illustrated in the accompanying drawings
For instance, the screw Jacks H H may be replaced by any suitable lifting
power, the construction of the lifting chains K be modified, and the lifting and
retaining pins replaced by equivalent devices so long as the discharge of the
respective functions required by my invention of the several parts used, as said
functions have been described, shall be provided for.

page_text: The practical advantages derivable from the use of my invention, as compared
with the use of the usual methods of building lofty bridges, are as follows
-
1. The erection of the girders may be proceeded with in many cases
on, the
ground, or on a scaffolding just above the water level alongside the piers, and the
girders erected under such conditions will cost much less than if erected upon a high
and narrow scaffolding
2 The erection of several girders may be carried on on the ground simultaneously,
instead of having to wait for the completion of high and expensive false works in
one, two, three, or more spans, before trying to place the girders over these or the
remaining spans
3. The construction of superstructure, cantilever, lifting tackle, and pins, tension
and compression bars, required by my invention is so simple that it can, as a
rule, be completed and taken down and put up again at a corresponding rate in a
few hours.
4. The pile-work for carrying the staging near the water lever for erecting the
girders upon will be much lighter, and consequently less expensive than if it had to
carry false works fifty, or a hundred, or a hundred and fifty feet high
5. Great economy inasmuch as by the use of my invention, the usual lofty and
expensive false constructions generally used hitherto, would be cut down to the
erection of a temporary staging just above the water level on which the girders could
be erected, or even this staging could be dispensed with altogether, and the girders
floated on barges alongside the piers.
The application of my invention to bridge construction has been described above
in such detail that its use for raising and placing girders, trusses, and the like
members of lofty structures, other than bridges, will be readily understood by
practical men
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is,
1. The combination of superstructure, cantilever, traverser, lifting power and
chain upon each of a pair of piers, and adapted for the purpose of raising and
placing a girder or pair of girders upon said piers, as set forth
2 The combination with a bridge pier or equivalent member of any span-
structure, of one super-structure, two cantilevers and traversers, and lifting tackle,
as set forth
3 The combination with a lifting chain and a girder-end, of tension and compression
bars, as and for the purpose set forth.
4 The combination of two superstructures, cantilevers, traversers, lifting powers
and chains, respectively situated at two points on the same level above the girder-seat,
and adapted thereby to the work of raising the said girder and traversing it on to its
seat as set forth
L1000