Field of the Invention
The present invention relates to a steel bridge having a single or double lane
carriageway. More particularly, the present invention relates to a construction of single lane
or double lane portable steel bridge. Furthermore, this invention also relates to a steel bridge
having a single or double lane carriageway, using detachable panels 3048 mm (10' -0")
long and 2160 mm (7' -1") high between pin hole centers and weighing approx 351 Kg
(normal type) and approx 443 Kg (heavy shear type) as load bearing girders on both sides of
the bridge. Further this invention also relates to a steel bridge having a single or double lane
carriageway along with other associated components to construct through type bridge, which
can be assembled and erected at site with components, that are transportable easily.
Therefore, this steel bridge, single or double lane, is convenient to dismantle, install and is
suitable for transportable easily.
Background of the invention and related Prior Art
In known bridge designs, the webs are constituted by a series of bars arranged in an
N-shaped structure. Some of these bars work in compression whilst others work in tension.
There is a need to provide for the military a temporary deep water port facility for
deep draft ships where adequate port facilities do not exist. This need for a deep water port
facility often occurs under circumstances where existing and available port facilities have
been damaged or do not provide sufficient space to handle cargo being loaded and
unloaded. In addition, there may be a need for a deep water port facility where one does not
currently exist or when operationally the best point of entry is determined to be across an
unimproved shoreline.

Many different requirements can be placed on a military bridge. For instance, it must
be possible to construct and lay the bridge quickly under field conditions with the use of the
minimum number of workmen, and it must also be possible to transport the bridge
components easily to the site at which the bridge is to be layed.
Among other things, these requirements have resulted in the construction of military
bridges from readily transportable lightweight aluminium-beam frameworks which can be
carried easily by personnel. Such aluminium frameworks, however, tend to become
particularly complicated, due to the requirements placed on the load bearing capacity of the
finished bridge. Consequently, a military or army bridge constructed from aluminium in
this way is expensive to produce.
German Patent GB2 540 267 teach collapsible beam structures for use in the
construction of military bridges. Each beam comprises plates which are mutually joined
together by means of dovetail couplings formed in the plates. Two such beams are placed
adjacent one another and connected together with the aid of cross-struts, to form a bridge
element. A plurality of these bridge elements are joined together in a row, with the aid of
bolts which extend between blocks mounted on the side-walls of each beam.
A double lane double-layer inverted tension steel cable bridge described in the
document CN2633942 with low cost and is capable of moving and making heavy cars
oppositely run. The steel cable bridge mainly comprises a tension arched cable, a bridge
cable, a bridge deck, a traffic lane board, a draw rod, a railing, a bracket, a tightwire
anchor, wherein, the tension arched cable is arranged below the bridge cable to form a
tension arched type double-layer structure, and an upper bearing cable is loaded by
utilizing the tensile force of a lower tension arched cable and a connect pole connecting the

upper bearing cable and the lower tension arched cable. When a movable load is on the
bridge, the downward transformation caused by the upper bearing cable automatically
releases the lower tension arched cable. When set up, the upper applied load automatically
reduces or disappears because of the tensile force of the lower layer cable, and the work
sagging of the bridge deck does not surpass the desired measurement of the span.
Therefore, the utility model is convenient to dismantle, install and convey, and is suitable for
the bridge for transportation, construction, and water crossing.
The document CN202187281 have stated a movable bridge type traffic lane. The
movable bridge type traffic lane is assembled by connecting a ramp bridge body, a traffic
lane bridge body, a connecting buckle plate and a marking rod. With the design, the
movable bridge type traffic lane can timely solve the vehicle pass when the road is flooded by
water, so that a traffic jam is avoided.
The document CN201778275 describes a deck structure of a cable bridge, which is
mainly used in dredging engineering of heavier vehicle flows during pre-construction of a
hydroelectric power plant. The cable bridge adopts the structure that an inverse tensional
cable is arranged below a steel beam mounted on a bridge abutment, steel cables extending
to ground anchors on both shores are symmetrically laid on the whole deck, the steel cables
and the steel beam of the bridge are in sliding connection through transverse positioning,
tensioning mechanisms are arranged on the steel cables of the deck, the static deck cross
slope is smaller than or equal to 2 degrees, and the maximum sag of the static deck midspan
is smaller than or equal to the clear span of the cable bridge /40 m.
The other document CN201678942 discloses a pavement inside dual-lane
beam-type bridge end reinforced concrete framework abutment base, which comprises two
parts including an abutment base and a retaining wall base. The abutment base and the

retaining wall base are combined into a whole through two rectangular shallow piles; an
inverted suspension plate base is arranged on one side on the two rectangular shallow piles,
a suspension connecting beam parallel to the inverted suspension plate base is arranged on
the other side, and one edge of the inverted suspension plate base is suspended outwards; a
telescopic gap ranging from 1 cm to 2 cm is arranged between the suspension connecting
beam and the inverted suspension plate base; two ends of the suspension connecting beam
are suspended outwards, and the lower surfaces of the heads of the suspended parts are
supported on the round shallow piles; and a buttress lower strip-shaped base and a wing
lug wall lower strip-shaped base are connected with the suspension connecting beam in the
direction opposite to the suspension direction of the inverted suspension plate base, and
used as the retaining wall base; the adoption of the base can save 30 percent of the
construction cost of the general rectangular solid abutment base; the piles are shallow, and
the construction is easy; and the base disperses the abutment centralized vertical axial load
and horizontal force load, and belongs to the framework structure.
The invention of CN20131790 states a lane tunnel bridge at a crossing. Left turn
exclusive annular ascent tunnels (1 and 2) are respectively arranged below upper and lower
main roads (7 ana1 8), and the tunnel entrances (3 and 4) are connected with descent roads
(5 and 6); the descent roads (5 and 6) are connected with the upper and the lower main
roads (7 and 8); tunnel exits (9 and 10) are connected with left and right main roads (11)
and (12); tunnel entrances (13 and 14) are arranged in the directions of the left and the right
main roads (11 and 12); left turn exclusive annular descent tunnels (15 and 16) are
arranged below the upper and the lower main roads (7 and 8) and are adjacent to the
tunnels (1 and 2); the exits (17 and 18) of the descent tunnels (15 and 16) are connected
with ascent roads (19 and 20); and the ascent roads (19 and 20) are connected with the
upper and the lower main roads (7 and 8). The lane tunnel bridge ensures that the left-turn

vehicles can run to the main roads along the tunnels, so as to realize turning left and ensure
smooth traffic.
According to the document DE3111874, a two-lane demountable bridge or flyover is
assembled from bridge sections supported on pier rows. These sections consist of orthotropic
plates which have cross-girders which are connected by at least one longitudinal girder and
into which hollow longitudinal ribs of trapezoidal cross-section are let in, and a cover plate
supported by the cross-girders and the longitudinal ribs. They have the width of a traffic
lane and are screwed to one another at the border between the two traffic lanes. The screw
connection in each case connects the cross-girders in a flexurally rigid manner via flange
rows welded on at their ends. Each traffic lane is supported only on one pier row. The flange
plate are located on the front side on the cross-girders and extend away in each case
continuously across all cross-girders of the plate. They extend upwards to on or above the
upper side of the cover plate and downwards to on or below the underside of the
cross-girders and are also welded on the cover plate. The welds are fillet weld. The piers are
arranged below the longitudinal girders which consist of a vertical web plate with a
horizontal lower boom and are reinforced above the piers.
Furthermore, the Patent Application No.882/KOL/2006 discloses the Bailey bridge
which were used and erected by various agencies like Indian Army, Border Security Force,
Indo-Tibetan Border Authorities and so on, to name just a few, in remote areas, particularly
in hilly terrain strewn with ravines, gorges and swift-flowing rivers. The wooden decks
required replacement at regular intervals due to natural decay, wear and tear and pilferage,
which posed a financial burden on the authorities for agencies. Moreover, due to the
National Policy of preserving forest cover and timber wealth, timber decks are becoming
scarce. The foregoing difficulties have been overcome by the present invention which
replaces the timber decks by stiffened deck units of predetermined dimensions. According to

this invention there is provided a single lane portable steel bridge of standard or extra width
with stiffened deck units comprising - (a) panel with panel pin and sway braces; (b) bracing
frame with bracing bolt, chord reinforcement with short chord bolt, and male/female end
post; (c) transoms equipped with transom clamp & raker; (d) said transoms in turn carrying
stringers which may be plain and/or of button type and (e) base plate fitted with bearings on
which rests the bridge structure, characterized in that the said stringer units carry stiffened
steel deck, junction stiffened steel deck at one end of the steel deck assembly, the said steel
decks being held in place by means of kerb unit(s).
The other document IN 201699 describes the girders are connected crosswise by
transoms, which are reinforced steeljoists, resting on the bottom chord of panels and carry
the roadways superstructure. These transoms are tied to the panel chords by suitable
holding means called "transom clamps" and fix the trusses in position at predetermined
distanced apart.
The invention of US5480106 consists of a core plug having at least one gap in the
circumstance of the core plug extending axially entirely through the plug so that the
diameter of the plug may be changed. The plug is provided with an opening on each side of
the gap to receive the end of a bridge. The bridge is provided at each end with a notched
portion capable of going through the opening in the core plug and a wider portion which is
not capable of going through the opening so that when the two ends of the bridge are
installed in the openings in the core plug the wider portion of the bridge biases the ends of
the core plug adjoining the gap outwardly to fit snugly within a steel coil. At the same time
the inner diameter of the steel coil captures the ends of the bridge and holds them firmly in
place.
The document US 6490745 discloses the method for constructing a continuous

composite steel girder bridge, comprising : placing a continuous steel girder over
predetermined spans; providing a heating source over the upper and lower parts of said
steel girder in order to provide an artificial temperature gradient along the steel girder;
casting and curing a concrete slab and composing the concrete slab on said continuous steel
girder having said temperature gradient; and offsetting tensile stress in the concrete slab
due to dead and live load, through the compressive stress occurring on the upper part of
said steel girder and said concrete slab, by removing the artificial temperature gradient after
said composing is completed.
An arrangement for projecting cantilever sections of multi-sectional bridge
supporting structures of steel and concrete and/or prestressed concrete forming a
superstructure which is supported on bridge piles, comprising at least one traveling
auxiliary beam movably carried on and arranged above said superstructure for spanning
between superstructure sections, two concreting scaffolds each comprising a supporting
part having crossbeams and rollers arranged above said superstructure, said rollers riding
on rails positioned above said superstructure, a platform suspended from said supporting
part of said scaffolds and arranged below said superstructure for carrying castings for
extending said projecting superstructure sections, a transport device movably carried on
said auxiliary beam so as to support therefrom said concreting scaffolds for transporting
said scaffolds between superstructure sections and from completed sections to a bridge pile
for beginning construction of the next section, said supporting part of each concreting
scaffold having longitudinal girders arranged adjacent said auxiliary beam, said crossbeams
of said supporting part being connected to said longitudinal girders and arranged below
said auxiliary beam, a pair of retractable supporting blocks supporting said auxiliary beam
on a pile next succeeding a completed superstructure section, said supporting blocks being
alternately retractable to allow passage of said crossbeams of said supporting part when
said scaffold is transported to said next succeeding bridge pile, and said platform of said

scaffolds comprising a bending resistant lattice formed by a plurality of longitudinally
extending platform girders and a plurality of platform cross-beams extending transverse to
said platform girders, each of said platform girders, each of said platform crossbeams
having inner and outer parts, said inner parts being movable with respect to said outer parts
to permit the formation of openings in said platform corresponding to the width of a bridge
pile to allow said platform to pass said pile as it is transported to the next section which has
been described in the document US4103861.
In order to avail further benefit and overcoming existing difficulties, the present
invention is developed to produce steel bridge with large torsional and flexural rigidity, with
improved response to the applied loads and with a prolonged life expectancy.
Summary of the invention
The present invention relates to construction of single lane or double lane portable
steel bridge of unique design, using detachable panels 3048 mm (10'-0") long and
2160 mm (7' -1") high between pin hole centres and weighing approx 351 Kg. (normal type)
and approx 443 Kg. (heavy shear type) as load bearing girders on both sides of the bridge
along with other associated components to construct through type bridge, which can be
assembled and erected at site with components, that are transportable easily.
At present, similar portable steel bridge is being manufactured by us, which can
span to bridge a gap of 200 ft. max. Presently need is felt for designing portable bridges of
longer span i.e. more than 200 ft.
Accordingly, the panels, which are also 3048 mm (10' -0") long, but 1448 mm
(4' -9") high between pin hole centres (weighing approx. 283 Kg.), used to construct present

portable bridges will not be able to sustain the load from such heavy bridge and a new panel
as described above has been designed to take care of such heavy loading and has been used
in newly developed/invented single lane & double lane portable steel bridges.
Detailed description of the invention with accompanying drawings
Although the disclosure hereof is detailed and exact to enable those skilled in the art
to practice the invention, the physical embodiments herein disclosed the invention which
may be embodied in other specific structure. While the preferred embodiment has been
described, the details may be changed without departing from the invention, which is
defined by the claims.
It is therefore an object of the present invention to provide a steel bridge having a
single or double lane carriageway.
The principal object of the present invention is to provide a steel bridge having a
single or double lane carriageway, using detachable panels 3048 mm (10' -0") long and
2160 mm (7' -1") high between pin hole centers and weighing approx 351 Kg. (normal type)
and approx 443 Kg. (heavy shear type) as load bearing girders on both sides of the bridge.
The other embodiment of the invention is to provide a steel bridge having a single or
double lane carriageway along with other associated components to construct through type
bridge, which can be assembled and erected at site with components, that are transportable
easily.
The other embodiment of the invention is to provide this steel bridge, single or double
lane, is convenient to dismantle, install and is suitable for the bridge for transportable
easily.

The other embodiment of the invention is to provide this steel bridge, single or double
lane, which is structurally stable, sturdy and capable of withstanding stress and strains
from design traffic load.
Another embodiment of the present invention is to using the bridge in different
manner enhance the possibilities of above. It has been found, as a result of investigations,
that this bridge has the advantages of reasonable structure, short construction period.
The other embodiment of the invention is to provide the steel bridge, single or double
lane, in which any one or more of the constituent components can be readily replaced
substituted with ease in the event of wear and tear due to atmospheric corrosion, or due to
craks or breakage on account of natural causes like earthquake.
The foregoing advantageous features will be described in detail and other will be
made apparent from the following detailed description of a preferred embodiment of the
invention that is given with reference to the two figures of the drawings.
FIG. 1 is a partial view in perspective showing panel in accordance with the invention.
FIG.2 is a view in transverse cross-section showing a panel in the bridge in
accordance with the invention.
The steel bridges, single or double lane, which comprise of following items/
components in combination -
(a) Detachable panels forming load bearing girders on both sides of the bridge;
(b) Bracing frames for holding the formed girders firmly in place;

(c) A plurality of transoms laid across the bottom chords of panels connecting
and spacing the main girders apart and at the same time carrying the
steel-decked roadway for allowing flow of traffic;
(d) A plurality of base plate and bearing assembly provided at both ends of the
bridge on which the terminals or ends of the aforesaid girders rest,
characterized in that the load-bearing girders are composed of a number of modular units
called panels (1) pinned together at ends and placed one after another to form multiple bays
each of 10 ft. length, if necessary and/or desired, and the entire structure is reinforced for
safety reasons by addition of chord-reinforcements (15) to the top and bottom of each row.
Load-bearing capacity of the girders are increased by adding extra panels alongside,
called herein as "truss", and row of panel put on top of panels, hereinafter called "storey".
These girders are connected crosswise by transoms, which are reinforced steel
joists, resting on the bottom chord of panels and carry the roadways superstructure. These
transoms are tied to the panel chords with bolts and fix the trusses in position at
predetermined distances apart.
End posts, male and female, are provided for connecting female and male lugs,
respectively, at tne end panels of each truss of the bridge for distributing the shear forces
due to end reaction of the bridge. These end posts attached to the ends of each truss of
bridge girder are supported on bearings which rest over base plates placed on the ground at
each end of the span. Such base plates are intended to spread the load from the bearings
evenly over an area of the ground.

Apart from above, sway braces are fitted diagonally between the transoms, and
vertical braces are also provided in between the transoms, to achieve greater rigidity of the
structure, as a whole.
A plurality of curb angles of varying lengths is fixed to the steel decks. The steel
decks serving as the road surface have serrated, honey-comb or ribbed structure to prevent
skidding of vehicles during passage over the bridge. These decks are of varying dimensions
and used in varying numbers for completion of the road surface.
The panel is made of high tensile steel, which along with other steel components are
shot-blasted to ensure removal of rust and mill scale. Then the components are given a
priming coat, usually a coat of red lead or red oxide-zinc chromate primer. The priming coat
is followed by two coats of finishing paint to specific customer requirement. If so desired, the
complete bridge may be supplied in galvanized condition and/or coated with special paint
like epoxy or poljyurethane to ensure prolonged resistance to adverse superincumbent
conditions.
The invention will now be described with reference to the accompanying drawings
i.e. an isometric view of the panel (Fig. 1) and an isometric view of the bridge assembly using
the panel (Fig.2).,.
Referring to Fig.2, it may be observed that panels (1) are joined end to end forming
the girders. Each pair of girders is firmly held in place by means of bracing frame (6). The
ends of panels are attached to post end (7), secured by panel pins (2). The bases of the post
ends (7) are made to place on base plate (11) carrying a plurality of bearing (10). Four such
base plate (11) and bearing (10) assemblies are provided at two ends of the bridge. Steel
decks (12) are placed on and secured to transoms (14) which are fixed to the girders by

means of bolt (4). These decks are held in place without any lateral displacement with the
help of holding down bolts. Steel decks are of varying dimensions, namely, long, short and
end decks. Accordingly, the curb angles (13) are also made of varying lengths.
The steel bridge of the invention in which end posts, male and female, are provided
for being connected to the female and male lugs at the end panels of each truss of the bridge
for distributing the shear forces due to the end reaction of the bridge. The said end posts
attached to the ends of each truss of bridge girders are supported on bearings which rest
over base plates placed on the ground at each end of the span and is intended to spread the
load from the bearings evenly over an area of the ground.
The normal panels are generally used in constructing the bridge. But heavy shear
panels may sometime be required in place of the normal panels at both ends of the bridge
for one, two, three bays etc., as per requirement at each end, depending upon the load
carrying capacity & span of the bridge.
The advantages and novel features of the invention will become more apparent from
the following detailed description when taken in conjugation with accompanying drawings
and these drawings are illustrative in explaining the constructional details of the system of
the invention. Such drawings are shown in two sheets.
Although, a particular exemplary embodiment of the invention has been disclosed in
detail for illustrative purpose, it will be recognized to those skilled in the art that numerous
variations or modifications of the disclosed invention, including the rearrangement in the
configuration of the scheduling aspects of the present invention as well as its method of use
being amenable to modifications on account of emerging needs in different types of settings
are possible.

As can readily be understood, the invention is not limited to the examples of
construction described in the foregoing and a large number of modifications may
accordingly be contemplated without thereby departing either from the scope or the spirit of
the invention.
It is obvious that the invention is not limited exclusively to the embodiments
illustrated and that many modifications can be made in the form, the disposition, and the
nature of some of the elements used in carrying the invention into effect, provided that these
modifications do not conflict with the provisions contained in each of the following claims.

We claim :
1. The steel bridges, having a single or double lane carriageway, which comprise of
components in combination -
a) Detachable panels forming load bearing girders on both sides of the bridge;
b) Bracing frames for holding the formed girders firmly in place;
c) A plurality of transoms laid across the bottom chords of panels connecting and
spacing the main girders apart and at the same time carrying the steel-decked road
way for allowing flow of traffic;
d) A plurality of base plate and bearing assembly provided at both ends of the bridge on
which the terminals or ends of the aforesaid girders rest,
characterized in that the load-bearing girders are composed of a number of modular units
called panels, pinned together at ends and placed one after another to form multiple bays
each of 10 ft. length, if necessary and/or desired, and the entire structure is reinforced for
safety reasons by addition of chord-reinforcements to the top and bottom of each truss.
2. A steel bridge, having a single or double lane carriageway, as claimed in Claim 1 in
which load-bearing capacity of the girders are increased by adding extra panels alongside.
3. A steel bridge, having a single or double lane carriageway, as claimed in Claim 1 in
which girders are connected crosswise by transoms, which are reinforced steel joists, resting
on the bottom chord of panels and carry the roadways superstructure.

4. A steel bridge, having a single or double lane carriageway, as claimed in Claim 1 in
which sway braces are fitted diagonally between the transoms, and vertical braces are also
provided in between the transoms, to achieve greater rigidity of the structure.
5. A steel bridge, having a single or double lane carriageway, as claimed in Claim 1 in
which a plurality of curb angles of varying lengths is fixed to the steel decks, which are
serving as the road surface have serrated, honey-comb or ribbed structure to prevent
skidding of vehicles during passage over the bridge.
6. A steel bridge, having a single or double lane carriageway, as claimed in Claim 1 in
which end posts, male and female, are provided for being connected to the female and male
lugs at the end panels of each truss of the bridge for distributing the shear forces due to the
end reaction of the bridge.
7. A steel bridge, having a single or double lane carriageway, as claimed in Claim 1 in
which said end posts attached to the ends of each truss of bridge girder are supported on
bearings which rest over base plates placed on the ground at each end of the span and is
intended to spread the load from the bearings evenly over an area of the ground.
8. A steel bridge, having a single or double lane carriageway, where in substantially
as hereinbefore described and illustrated with particular reference to the accompanying
drawings.

ABSTRACT

The present invention relates to a steel bridge having a single or double lane
carriageway. More particularly, the present invention relates to a construction of single lane
or double lane portable steel bridge. Furthermore, this invention also relates to a steel bridge
having a single or double lane carriageway, using detachable panels 3048 mm (10' -0")
long and 2160 mm (7' -1") high between pin hole centers and weighing approx 351 Kg
(normal type) and approx 443 Kg (heavy shear type) as load bearing girders on both sides of
the bridge. Further this invention also relates to a steel bridge having a single or double lane
carriageway, along with other associated components to construct through type bridge,
which can be assembled and erected at site with components, that are transportable easily.
Therefore, this steel bridge, single or double lane, is convenient to dismantle, install and is
suitable for transportable easily.