FR2547844A1 - Bridges with cross-linked (reticulate, lozenged) bearing structure made of steel profiled sections or tubes - Google Patents

Abstract

The invention relates to the construction of road or railway bridges comprising a bridge floor (table) 3, which may or may not contribute to the general flexure of the construction and rests on a cross-linked bearing structure made of steel profiled sections or tubes. This structure comprises at least one girder 11A and two end struts 11B. The girders, attached or separated, comprise upper frames 11Aa, 1ower frames 11Ab fitted with bearing components 11Ac, diagonals 2A, uprights 2B and optionally cross-pieces 2C and crossbracing bars 2D. The end struts comprise end cross-pieces 11Ba and optionally end diagonals 11Bb. This invention has very widespread applications in the field of public works (civil engineering); it can be used in all countries.

Description

The present invention relates to manufacturing, construction and launching processes and the specific components to contribute to the production of cross-linked load bearing bridges in steel sections or tubes comprising an apron resting on at least one cross-linked beam in sections or tubes. of steel, this deck itself being a roadway
b at least one lane for motor vehicle traffic, at least one railway line, with or without sidewalks for pedestrians, or a combination of these various bodies, works that have never been done to date.

 Deck girder bridges are an important category of structures for all types of traffic. The most common bearing structures for these structures are solid-girder beams or box girders whose constitutive material is concrete or, more rarely, steel.

 They are massive and therefore heavy structures whose supports are at around 60 m.

Despite the progress made in the field of prefabrication, the construction processes are very close to the construction site techniques, require significant equipment and personnel resources and are very sensitive to climatic hazards.

These are also techniques that can not be exported, except obviously in the form of know-how and means, but we know that any superiority in this area can be quickly questioned.

 The structures according to the invention have intrinsic advantages which should enable them to impose themselves on the market of medium-span structures, between 60 and 100 m. The reticulated structure allows optimal use of the material, which is concentrated just where it is needed. Steel has the property of resisting in compression as well as in tension or shear.

Steel profiles and especially construction tubes are semi-finished products whose characteristics and tolerances are perfectly defined. The assemblies of such profiles have a very remarkable aesthetic related to the regularity, modularity and the repetition of simple patterns having a shape pleasing to the eye. The works according to the invention are lighter than their traditional counterparts, they require simple and light means of launching, they lend themselves to an industrialization pushed by the reduction and the standardization of the ncmbre of the necessary parts, they make it possible to reduce and to simplify as necessary the operations of the building site which become the continuation of the operations in factory and are similar to mechanical engineering, they make possible the complete export of spare parts similar to that of turnkey factories, they finally allow a significant reduction in construction time, factory operations and transport that can be achieved during the construction of the access roads and since, the advantage is all the more marked that the site is located in a distant country.

 Finally, the possibility of making structures of the order of 100 m without intermediate supports makes these structures particularly suitable for constituting mcyens of crossing of arms or estuaries, where the reduction of the number of supports brings an eccnomony considerable.

 The basic shape of the crosslinked structure is a triangular section beam whose pattern is a right-angled or diamond-shaped pyramid with a top pointing towards the pile or upwards.

 The advantages of this form, for a rigidity to torsion and buckling that is apparent to the box, is an optimal resistance to bending and shearing with regard to the amount of material used, which is the characteristic of all crosslinked structures.

 These beams comprise lower chords, upper chords and diagonals or these amounts connecting the peaks of the pyramids to the vertices and possibly the middle of two or four sides of the base of these pyramids.

They may also include cross members and bracing bars, but these members may be removed when the deck members can play their role.

 The frames, the diagonals and possibly crosses and braces consist of steel profiles and in particular rectangular section tubes, circular or even polygonal.

 The ribs, particularly lower, can be reinforced either from the inside, especially by introduction of tubes or more generally from profiles or mcyen preloading cables, or from the outside by welding reinforcing profiles. It is also possible to reconstruct box-like members by metal construction processes when the service requirements require larger sections or inertia than those of the fabricated tubes. We can finally build the frames using several tubas contiguous, a technique that seems especially justified with rectangular section tubes.

 According to a first variant, called variant 1., the cross-linked beams, and in particular the ribs, are made of mcyen rectangular section profiles, which allows a great simplification of assemblies. Indeed, as the faces are flat, the sections in contact are also, and therefore, even if they are biased relative to the generatrices of the profiles, their execution in the factory is easy.

The assemblies are then made by welding, with cu without the interposition of plates to facilitate the docking of the tubes or profiles.

 In variant 1., apart from possible aesthetic considerations, nothing prevents diagonals and possibly crosspieces and braces from being tubes with a circular or polygonal section.

 melon a variant of this first variant, called variant 1.1., the crosslinked beams are formed of sections comprising several patterns, these sections being mounted on the site from flanks manufactured in factory or on site.

The third face of the prism is then generally constituted
slab by steel deck elements derived from the orthctrope, also prefabricated, or any element of generally planar shape and intended to serve as formwork and possibly reinforcement to a concrete slab, but it can also be formed of sleepers and bracing. In this case, the beam is suitable after launch to receive a deck not or partially participating.

 According to another variant of variant 1, called variant 1.2., The cross-beam beam sections are entirely machined at the factory or on site. They then comprise flanks assembled by a memtrure and either crossbeams and braces - with the exception of the end crosspieces, in order to allow the assembly of the upper chords by welding around the entire periphery of said chord - either elements stiffened plates derived from the orthotropic slab, or any element intended to formwork and possibly reinforcement to a concrete slab.

 Although this provision does not lend itself to long-distance transport because of the bulk of the beam elements, it can be justified for sites close to the manufacturing plant, because of the large share of added value in the workshop. .

What characterizes variant 1.1. Is that the mem
lower burr of the beams comprises at least two profiles.

What characterizes variant 1.2., Is that the chord
The bottom of the beams may have only one profile.

 According to a second variant, dencméè variant 2., the crosslinked beams consist of profiles or tubes of any section. To maintain assemblies the simplicity that attaches to the flat sections, the assemblies are made using prefabricated assembly nodes, which is the variant called 2.1.

of variant 2., either by means of prefabricated fastening devices, which constitutes the variant referred to as 2.2., or by direct welding using the so-called "snapdragon" device.

 In the case of variant 2. in general, the use of assembly nodes or piecing devices allows the implementation in chords members of bars of length corresponding to that of the pattern. This arrangement is very favorable from the transport point of view since, at the same weight, the volumes are reduced to those of the bar sections and the assembly nodes or attachment devices.

The assembly nodes are formed by molding or by mechanical welding. They generally comprise male sleeves, or females intended to receive the elements of frames or the diagonals. The sleeves for receiving the chords are, for reasons of simplicity of mnntage, female sleeves in at least two parts having a shape adapted to that of the section of the frame, ie the shape of a
L in the case of ribs with rectangular section and that of a semicircle in the case of ribs with circular section. One of the parts of the knot carries the sleeves intended to receive the diagonals; it is called the active part of the assembly node.

The other part, which generally has no function other than to ensure the longitudinal integrity of the corresponding part.
of the chord, is called passive part of the assembly node.

 To facilitate the mnntage operations, the active part is provided with lugs or other organs to ensure its precise positioning on the chord.

Assemblies made using prefabricated knots have many advantages
- rigorous centering of the tubes
- convergence of the lines of axes
- removal of bias cuts
- easier execution of welds;
- possibility of marry shape section tubes
different
- possibility of creating complex spatial structures;
- possibility of using chords, especially lower,
of circular section, which allow to cash
more severe solicitations.

 With regard to the fastening devices, they are formed from two half-shells matching the shape of the section of the frame, ie an L in the case of rectangular section members and semicircle in the case of ribs with circular sections. They are then formed by folding a sheet of steel of sufficient thickness. When the frame is a polygonal section tube, the half-shells will be formed generally by molding and have an outer face with polygonal section or possibly circular.

 The half-ccquille intended to receive the diagonals is called half-shell active, the other being called passive half-shell. As in the case of assembly nodes, the active half-shell may include a positioning means on the frame.

When the active deí-ccquille has plane faces, that of these faces which receives the diagonals, called face of
Junction, is provided with centering lacquers sheet of sufficient thickness, whose circumference allows to put in place exactly cu the tubes to receive, given the manufacturing tolerances of said tubes or profiles.

 Centering plates are attached to the joining face.

by means of weld points made inside notches1
so as not to interfere with the accuracy and rigor of the centering.

 When the active half-shell does not have a flat outer face, is fixed on it by welding one or more planar junction faces, which are said in this case reported folded sheet of sufficient thickness. These reported junction faces are also provided with centering plates.

 Nothing prohibits, when the active half-shell has flat faces, to provide it with junction faces reported, this in particular to facilitate assemblies by cutting off slants bias or ensure better convergence of the axes of the bars, which is a desired condition in crosslinked construction.

 There is no prohibition to marry in the same structure assembly nodes and fastening devices, for example to put assembly nodes on the lower chord, which ensures a good balance of disgcnales during the mnntage and upper hoop fasteners which permit easier handling of the upper ends of the diagonals for adjustment in position.

 There is no prohibition on making assembly nodes or attachment devices comprising two active parts, which would make it possible, for example, to produce multilevel spatial structures.

Nothing prevents the fixing of centering plates
(Fig. 29 to 33) on the docking plates (Fig. 3) or even on the joint faces of the frames, if these are planar.

 There is nothing to prevent the replacement of joint faces (Figures 31 to 33), in the case of flat-face frames, with anchor plates, which are themselves equipped with centering plates.

 In both variants 1. and 2. described above, the stiffened plates derived from the orthotropic slab comprise a steel decking, stiffening buckets and two half-spacers formed of a Z-shaped profile whose upper part receives the decking. and whose lower part is intended to be welded to the homologous element of the following plate to form a U-shaped profile whose opening is equal to that of the stiffening buckets.

 During assembly, the remainder of the entroise and the two free edges of the plate are welded to the upper chord. The top of the spacer is then closed by a cover of the same thickness as that of the decking.

Parts and operations of machining or assembly represent
in the figures are identified by reference to the nomencla
detailed description below.

1 Member
He covers-joint
1a Active half-shell
Passive half-shell
the reinforcement
IF Platinum of solidarity
2 Diagonal, amount, crosses, bracing
2A Diagonal 23 Amount
2C Traverse
2D Bracing
3 Apron
3A Decking
33 Auget
3C Spacer
3Cb Half spacer profile
3Cc Opercule
4 Fastening device
4A junction face
4Ab Junction face reported
43 Centering plate
4Ba Notch
4D Berth
5 Assembly node
5B Active part
5C Passive part -5D isranchon
8 Welding Il Overall work
11A Beam
llA choir upper
11Ab Lower Chord 11Ac Support Piece
113 Spacer
11Ba Crossbeam
11Bb Diagonal of about - Figure 1 shows an example of a basic element in the case of
variant 1, when the upper face of the beam is
triangulated itself - Figure 2 shows the same basic element when the face
upper beam is a stiffened part plate element
cipante.

- Figure 3 shows a cross section corresponding to the
figure 1.

FIGS. 4, 5 and 6 show successively the diagram of
appeared from a prefabricated flank and two possible forms of
prefabricated flanks, that corresponding to figure 6
to remove the low docking plates.

- Figure 7 shows the assembly diagram of a completed section
at the factory according to variant 1.2.

FIG. 8 shows the example of reinforcement of a chord
by means of an inner tube with a circular section joined to the
two ends of the chord tube by means of plates.

FIGS. 9, 10 and 11 show three modes of assembly of
two twin tubes for lower chord, to ensure
the integral transmission of efforts respectively cashed
by external profiles and reinforcing tubes.

Figure 12 shows the principle of assembling two sections
lower chord consisting of four section tubes
rectangular contiguous; the hidden walls of the tubes must
be considered as reinforcements of the tube formed by the walls
apparent, their continuity must therefore be ensured by welding,
what the recesses in the tubes allow.

 Figure 13 mcntre a box-shaped reconstituted chord.

FIG. 14 shows a reconstituted half-chord derived from
Figure 6.

FIG. 15 shows an example of a spatial structure formed at
using three adjoining beams.

- Figure 16 shows another example of. spatial structure
formed using three contiguous beams. It will be noticed that,
in this case, the tops of the pyramids are directed to the
above.

- Figures 17 and 18 give the principle of the assembly of
two stiffened plates, at the right of the spacer.

- Figures 19 and 20 give the principle of the assembly of
diagonals on an upper (or lower) chord with
docking plate, in cross-section and in elevation.

- Figures 21 and 22 give the principle of the assextl2ge of
diagonals on a lower (or higher) chord with
access plates, in cross section and in elevation.

FIG. 23 shows by way of example a cross section of a
a work with two piers, each with a rib
lower formed of two contiguous tubes.

- Figure 24 gives the principle of an assembly node to
female sleeves, after assembly - Figures 25, 26, 27 and 28 show the principle of knots
two-piece assembly for receiving members
lower cu upper rectangular section cu circular.

- Figures 29, 30, 31, 32 and 33 give the principle of
fasteners for receiving lower frames
upper cu with rectangular section cu circular.

FIG. 34 details the principle view of a work comprising
two beams.

- Figure 35 gives a perspective of a book with
two beams - Figures 36, 37, 38, 39, 40, 41, 42 and 43 show the phases
successive stages of the construction and launching of a structure
supporting structure made of steel profiles
Fig. 36: Floor assembly of the first sections.

 Fig. 37: Launch of the first sections.

Fig. 38: Floor assembly of the following sections and
fastening to the first sections.

 Fig 39: Launching a beam.

Fig. 10: Descent of the beam and lateral displacement on
support.

Fig. 41: Assembly of two beams by means of plates
between beams.

Fig. 42: Completion of the deck by fastening the plates
under pavements;
Fig. 43: Installation of prefabricated sidewalks and guard
ccrps, sealing, and the diaper
rolling, painting of the work.

- Figures 44 and 45 give the principle of the manufacture of a
beam section according to variarrte 1.1.

 Fig. 44: Manikin assembly of prefabricated sides.

 Fig. 45: Solidarization by means of stiffened plates.

- Figures 46 and 47 give an example of basic element according to
variants 2.1. and 2.2.

 Fig. 46: Base element with assembly nodes.

 Fig. 47: Base element with fastening devices.

- Figures 48, 49, 50 and 51 give the principle of realization
a beam according to variant 2.

Fig. 48: Assembly on form of the possible reinforcements of
the lower chord.

Fig. 49: Placing diagonals with the help of
sleeves knots or centering plates
fasteners.

 Fig. .50: Laying the upper chords.

Fig. 51: Set up and welding of the assembly nodes
or fastening devices.

 We now consider successively the operations carried out in the factory (referred to above as manufacturing), transportation from the factory to the site and finally the operations carried out on the site (denominated above construction and launch).

 In the case for example of a structure according to variant 1.1.

cControl two beams whose lower chord is formed of two tubes contiguous with internal reinforcement, we can distinguish the following successive phases
I. Operations.made in the factory (manufacture)
Fabrication of chord tubes (Fig. 1) and cutting
throughout the project.

Ib) Cutting reinforcing tubes (Fig. 8), manufacturing
and welding the plates to the reinforcing tubes (Fig. 10).

Ic) Introduction of reinforcing tutes in the tubes
lower chords, welding plates to
extremities of the lower chord tubes (Fig. 10).

Id) Manufacture of diagonal tubes and execution of
cuts: bias (Fig. 3), possible manufacture of
berths (Fig. 3).

Ie) Mannequin assembly of the flanks (Fig. 4 and
5 or 6), diagonally welded to the ribs
with the interposing of any plates.

If) cutting decking plates- (Fig. 2) in
holding count of the position in the book
under pavements, on beams, between beams (Fig. 23).

Ig) Manufacture and decoupling of stiffening buckets
of the orthotropic slab (Fig. 2).

Ih) Manufacture and cutting of: L-sections for
banks of the structure (Fig. 23).

Ii) Production and cutting of Z-sections for 1t2
spacers of the orthotropic slab (Figures 2 and 18)
adapted to the width of the decking boards
(Fig. 23).

Ij) Decopage of: Lids for closure of-s between
toises (Fig. 18), adapted: to the width of the plates
decking (Fig. 23).

Ik) Fabrication of stiffened plate elements (Fig. 2
and 23).

II. Transport from the factory to the shipyard
II.A) Flanks (fig.4).

 II.B) Tight plates (Fig. 2).

 II.C) Opercules (Fig. 18).

III. Operations carried out on the site (construction and
launch) III.1) Sidewall dummy assembly (Fig. 44) III.2) Solidary beam section manufacture
by means of stiffened plates - <fig. 45) III.3) Floor assembly of the first sections (Fig. 36).

 III.4) Launch of the first sections (Fig. 37).

111.5) Floor joining of the following sections and fixing
to the first (Fig. 38).

 III.6) Launch of a beam (Fig. 39>.

III.7) Descent of the beam and lateral displacement
on supports (Fig. 40).

111.8) Assembly of two beams by means of elements of
stiffened plate (Fig. 41)
III.9) Completion of the deck by fastening the plates under
sidewalks (Fig. 42).

 III.10) Finishes of work (fig 43).

In the case of a structure according to var-iante 2.2, comprising for example three crosslinked beams, chaeune it having a lower chord formed of a circular tube, two upper chords formed of a rectangular section tube and diagonals formed of circular section tubes, the following successive phases can be distinguished
I. Factory Operations (Manufacturing)
I.a ') Manufacture and cutting of sections of
lower chord (Fig. 47).

I.b ') Manufacture and cutting of sections of
upper chords (Fig. 47).

 I.c ') Production and cutting of the diagonal tubes (Fig. 47).

 I.d ') Manufacture of fasteners (Fig. 47).

 I.e ') (absent).

 I.f ') (identical to I.f)) (Figs 47 and 23).

 I.g ') (identical to I.g)) (Fig. 23).

 I.h ') (identical to I.h)) (Fig. 23).

 I.i ') (identical to I.i)) (Figs 47, 18 and 23).

 I.J1) - (identical to I.j)) (Figs 18 and 23).

 I.k ') (identical to I.k)) (Figs 47 and 23).

II. Transport from the factory to the shipyard
II.A11) Lower chord tubes (Fig. 47).

 II.A'2) Upper chord tubes (Fig. 47).

 II.A'3) Diagonal tubes (Fig. 47).

 II.A'4) Fastening devices (Fig. 47).

 II.B ') (identical to II.B)) (Fig. 47).

 II.C ') (identical to II.C)) (Fig. 18).

III. Operations carried out on the construction site (construction
and launch):
III.1.1) Manikin construction of the pyramids (Fig. 49:
by means of the fastening devices (Figures 30 and 31:
III.1'.2) Laying the upper chords (Fig. 50).

III.1'.3) Installation of passive half-shells (Figures 30, 31 and 5
III.1'.4) Overall setting and welding of devices
attachment (Fig. 51).

 III.2i to 12 ') (analogous to 111.2 to 12)) (Figs 36 to 43).

 The object of the invention can be achieved anywhere in the world. It can take straight or biased shapes or any other form. It can receive all types of traffic.

 It is particularly interesting for the equipment of developing countries since its realization is entirely made from prefabricated elements and that it does not require any heavy industrial infrastructure.

 The launching device is particularly simple and can be reused a significant number of times, it is moreover interchangeable with respect to the realized works.

 Welding operations are carried out in the best possible conditions (in the factory, on the ground, on structures from above).

 The laying of sidewalk plates, when corbelled, requires only support material, ~ which has not been shown.

 Only the painting of the structure requires the presence of personnel under the deck or structures.

 This type of structure allows significant time savings and can ensure in economic conditions crossing either medium gaps or difficult sites (including aquatic) over long distances.

Claims (9)

REVEi: DI CATIONS 1. Bridges characterized in that they comprise a bearing structure réti  abutment in profiles or steel tubes formed of lower chords and  diagonals and possibly uprights, supporting a  apron, whose manufacture, construction and launch can be fully industrialized. Bridges according to claim 1, characterized in that the assemblies  between sections or tubes of steel, of any shape, are  made by direct welding in the form of "wolf jaws". 3. Bridges according to claim 1. characterized in that the profiles used for the chords have flat faces and that the  Assernhlages are flat welded sections. 4. Bridges according to claim 1. characterized in that the assemblies  between sections or tubes of steel, of any shape, are  made using prefabricated fastening devices having at least one junction face and allowing the mounting of structures to  from elementary bars. Bridges according to claim 1, characterized in that the assemblies  between sections or tubes of steel, of any shape, are  made using prefabricated assembling nodes allowing the assembly of structures from elementary bars. Bridges according to claim 1, characterized in that the bars  more solicited are reinforced by juxtaposition of several profi  the. 7. Bridges according to claim 1. characterized in that the most stressed bars are reinforced from the inside. Bridges according to claim 1, characterized in that the bars  more stressed are reinforced from the outside.  are reconstituted in the form of prismatic boxes.  Bridges according to claim 1, characterized in that certain bars