The present invention relates to the field of mobile bridges suitable for highway traffic loads. More particularly, it relates to a transportable, pre-fabricated module which can be combined on site with other similar modules to construct a simple-beam road bridge for spanning between two suspension or support points.
BACKGROUND OF THE INVENTION
Containerized bridge modules can be easily transported and quickly assembled to provide a temporary or permanent roadway across otherwise impassable terrain. Such containerized bridge systems may be deployed in a military or civilian context, for example to expedite disaster relief to inaccessible regions, for providing temporary traffic relief, or as permanent or semi-permanent bridge constructions. In the context of this invention, containerized bridge systems may be used to construct road bridge spans of between 50 ft (15 m) and 300 ft (90 m) or more. As known in the prior art, the concept of containerized bridge modules referred generally to modules which were capable of being transported in shipping containers, or loaded on to pallets such that the palletized modules are transportable by container.
PRIOR ART
It is known to provide elements of floating or pontoon bridges in containerized form. Examples of such systems can be found for example in German patent application DE10021806A1 or international application WO2012/110401 A1. However, the purpose of such containerized pontoon bridges is to provide buoyancy and load distribution over several modules, and they are not suitable for constructing a simple-beam section which can be suspended or supported at its end regions.
UK patent application GB2250046A describes a containerized portable bridge kit for low load class vehicles of approx. MLC5 (Military Load Class), in which bridge section components are arranged such that some of them form a container in which the other components are transported. The components include structural beam components and deck components for fitting on to the structural beam once the latter is assembled. Such a bridge kit requires an extensive assembly procedure before the bridge can be deployed.
German patent DE3810071C1 describes a suspension bridge construction which is described as modular, in which each bridge section, or element, reaches from one suspension/support point to the next. The elements vary in length accordingly, and are assembled from units which can be loaded into containers and have an underspanning which permits an assembled element to have a length up to 36 m. Units may be abutted end-to-end. Transoms join adjacent elements at the suspension points, and each bridge section is assembled from several different parts in modular length. The road deck comprises multiple elements set end to end. Multiple suspension cables are used to enable adjustment of the hanger heights during the launching of the successive bridge elements into position. Bridge modules comprise a superstructure, and are lifted into position and fitted with an underspanning truss substructure. Support is provided at each junction between successive bridge elements. For long spans, such a method requires long bridge modules which are cumbersome to transport and maneuver. The necessity for a superstructure on the bridge modules restricts the number of ways in which the bridge elements can be combined to provide different bridge configurations, and the underspanning arrangement makes it difficult to assemble the elements.
BRIEF DESCRIPTION OF THE INVENTION
The invention described in this application seeks to overcome the above and other difficulties inherent in the prior art. In particular, the invention aims to provide a bridge beam module according to claim 1 and a method of constructing a bridge according to claim 15. The bridge beam module is easily and quickly deployed and attached to other similar modules to form a simple-beam bridge span which can be launched using standard methods. Since the medial portions and the deployed lateral portions of the road deck serve as the upper chord of the simple beam structure, by transmitting axial load along the length of the simple beam structure, a superstructure is not required, and the bridge beam modules can be combined in many different ways to provide different roadway configurations. The size and configuration of the bridge beam module of the invention are such that it can not only be transported as a standard shipping container, but can also be quickly deployed to provide an uninterrupted roadway width of as much as 25 ft (7.5 m), which is sufficient to accommodate two lanes of road traffic. Using bridge beam modules such as the module described here, it is possible to erect a self-supporting, single-span, simple beam bridge which can be up to 200 ft (60 m) or more in length, with an uninterrupted road-deck plane which can be 20 ft (6 m) or even 25 ft (7.5 m) wide, in a matter of hours.
The invention and its advantages will further be explained in the following detailed description, together with illustrations of example embodiments and implementations given in the accompanying drawings, in which:
FIG. 1 shows in schematic side elevation a first example of a simple-beam road bridge span comprising a single simple-beam assembly of bridge beam modules according to the invention.
FIG. 2 shows in schematic side elevation a second example of a pier-supported road bridge span comprising two simple-beam assemblies of bridge beam modules according to the invention.
FIG. 3a shows in schematic side elevation a third example of a suspended road bridge comprising four simple-beam assemblies of bridge beam modules according to the invention.
FIG. 3b shows in schematic side elevation a fourth example of a supported single-span road bridge comprising six bridge beam modules and underspanning, according to the invention.
FIG. 4 shows in schematic side elevation an example of a launching method for the road bridge span of FIG. 1.
FIG. 5 shows a first schematic perspective view of a simplified example of a truss arrangement of a bridge beam module according to the invention.
FIG. 6 shows a second schematic perspective view of the truss arrangement of FIG. 5 showing upper and lower chord members and articulation of lateral truss members.
FIG. 7 shows in schematic end elevation an example of a bridge beam module according to the invention in its extended state (deployed configuration).
FIG. 8 shows in schematic end elevation the bridge beam module of FIG. 7 in its retracted state (transport configuration).
FIG. 9 shows in schematic side elevation the bridge beam module of FIG. 7 in its extended state (deployed configuration).
FIG. 10 shows in schematic side elevation the bridge beam module of FIG. 8 in its retracted state (transport configuration).
FIG. 11 shows a schematic cross-sectional view of an example of a contact zone of two abutting upper chord members (road deck ends) of adjacent bridge beam modules 2 in the same simple-beam bridge span, illustrating an elastic deformation zone of steel in the vicinity of the contact zone.
FIG. 12 shows a schematic cross-sectional view of the example contact zone of FIG. 11, illustrating an axial retaining arrangement for resisting a parting of the two abutting upper chord members of the simple-beam bridge span.
FIG. 13 shows a schematic cross-sectional view of the example contact zone of FIG. 11 or 12, illustrating a locating dowel arrangement for transferring shear forces between the two abutting upper chord members (road deck ends) of the simple-beam bridge span.
FIG. 14 shows a schematic cross-sectional view of an example of a contact zone between the two abutting upper chord members (road deck ends) of two abutting simple-beam bridge spans, illustrating an axial retaining element for resisting an axial parting of the two abutting simple-beam bridge spans and a transom element for supporting the two ends of the two abutting simple-beam bridge spans.
FIG. 15 shows a schematic cross-sectional view of the contact zone of the abutting upper chord members (road deck ends) of the abutting simple-beam bridge spans of FIG. 14, illustrating an elastic deformation zone of steel in the vicinity of the contact zone in relation to the supporting transom.
FIG. 16 shows a schematic plan view from below of the ends of two upper chord members (road deck ends), illustrating a reversible locating dowel arrangement and a corresponding transom arrangement.
DETAILED DESCRIPTION OF THE INVENTION
The invention will now be described in detail with reference to the drawings. Note that the drawings are intended merely as illustrations of embodiments of the invention, and are not to be construed as limiting the scope of the invention. Where the same reference numerals are used in different drawings, these reference numerals are intended to refer to the same or corresponding features. However, the use of different reference numerals should not necessarily be taken as an indication of a particular difference between the referenced features.
As shown in FIG. 1, a simple-beam bridge span 1 can be used to construct a clear-span road bridge across a space 5 such as a river, the simple-beam bridge span being supported at its end regions 4, for example on prepared foundations or excavations in the soil or rock. In the example, the road bridge span 1 provides a more or less contiguous road surface for vehicles or other traffic to pass unimpeded across a road deck 6 inserted between road sections 3.
The single simple-beam bridge span 1 illustrated in FIG. 1 comprises four bridge beam modules 2 arranged and secured end-to-end to each other. Truss members 8 transmit shear stress between the upper and lower chord members 6 and 7. The upper chord members 6 are abutted end to end with one another such that axial compression stress is transmitted axially along the whole road deck of the bridge, thereby fulfilling the function of the upper chord of the simple beam structure 1 as a whole. The lower chords 7 are connected by ties 9 to transmit tension load between the lower chord members 7 of adjacent bridge beam modules 2, such that the tied lower chord members 7 fulfill the function of the lower chord of the simple beam structure 1 as a whole. In the illustrated example, each bridge beam module 2 may be 40 ft (12 m), 30 ft (9 m) or 20 ft (6 m) long, for example, and the overall bridge span 1 may thus be 160 ft (48 m) long. As will be described below, each 40 ft (12 m) long bridge beam module is configured such that it can be transported and handled as a standard 40-foot shipping container.
FIG. 2 shows an example of a pier-supported road bridge span comprising two simple-beam assemblies of bridge beam modules according to the invention. A first simple-beam span 11 comprises three bridge beam modules 21, which may be of 40 ft (12 m) each in length, for example. The first span 11 is supported at one end 4 on the ground, and at its second end by a pier 10. As will be described below, a transom element (not shown) can be provided to transmit the load from the road deck 6 to the pier 10. The road decks 6 of adjacent bridge beam modules 21 are abutted end to end such that axial compression stress is transmitted axially along the whole road deck 6 of the bridge span 11, thereby fulfilling the function of the upper chord of the simple beam structure 1 as a whole. Ties 9 are fitted between the lower chord members 7 of adjacent bridge beam modules 21 to transfer tension load between the adjacent lower chord members 7, thereby fulfilling the function of the lower chord of the simple beam structure 1 as a whole.
The bridge of FIG. 2 also comprises a second simple-beam bridge span 12, comprising three bridge beam modules 22, 22′ arranged in a similar fashion to those of the first simple-beam span 1i and supported at one end on the ground 4 and at the other end on the pier 10. In this example, the pier 10 supports the road decks 6 of the first and second simple-beam spans 11 and 12. By providing support at the upper chord member 6, the abutment joint 20 between the ends of the adjacent simple beam spans 11 and 12 can be arranged to allow for a modest vertical angular movement of the spans relative to each other while still maintaining the abutment and therefore a transmission of axial load between the upper chord members 6 of the adjacent bridge spans 11 and 12. Note that the second bridge span 12 in the illustrated example comprises two bridge beam modules 22 of 40 ft (12 m) each in length and one 22′ of 30 ft (9 m) in length. The overall length of the bridge is thus 230 ft (69 m). The bridge beam modules of the invention may advantageously be supplied in various predetermined lengths in order to facilitate construction of different bridge lengths by combining bridge beam modules 2 of different lengths. The lengths may advantageously be chosen as lengths which correspond to standard shipping container lengths, and may thus be provided in lengths of multiples of approximately 10 ft (3 m). As will be described below, the width and height of the bridge beam modules 2 are also advantageously chosen to correspond to the width and height of a standard ISO container (8 ft, or 2.438 m and 8 ft 6 in, or 2.591 m respectively), and the modules 2 may be provided with the eight lash-lift points required for standard container freight. Such lash-lift points may be formed as an integral part of the module, or they may be fitted to the module. The beam bridge modules 2 thus each have cross-section dimensions 22, 23 of a standard shipping container and a length of substantially 10 ft, 20 ft, 30 ft or 40 ft, when fitted with end elements comprising the standard corner fittings of standard shipping containers, corresponding to standard container lengths of 10 ft, 20 ft, 30 ft or 40 ft.
FIG. 3a shows how a suspension bridge may be constructed as four simple-beam spans 1 of bridge beam modules 2 according to the invention. Overhead support is provided by ropes or chains 12, via pylon elements 13. The bridge load is transmitted to the ropes 12 by transoms 11 located under each junction between adjacent simple-beam spans 1. In the illustrated example, four beam spans 1 are shown, each comprising three bridge beam modules 2 of 40 ft (12 m) in length, giving a total bridge length of 480 ft (144 m). As with the examples of FIGS. 1 and 2, the bridge beam modules 2 of each simple-beam bridge span 1 are arranged such that their upper chord members 6 (i.e. the road deck) abut in an axial-load transmitting fashion, and their lower chord members 7 are tied by connecting members 9 in a tension load transmitting fashion, thereby fulfilling the functions of upper and lower chord members of the respective simple-beam bridge span 1 as a whole. Note that no ties 9 are required between the lower chord members 7 of adjacent bridge spans 1, in order to permit an angular movement in the vertical plane between the road deck 6 of the end module 2 of one bridge span 1 and the road deck 6 of the abutting end module 2 of the adjacent bridge span 1.
FIG. 3b shows a single-span example of a road bridge 1 assembled from six 40 ft (12 m) bridge modules 2 of the invention. Such a span 1 could support itself and carry significant traffic load, thanks to the large depth (vertical separation of the upper and lower chords of the simple beam) of the modules 2. In this example, however, an underspanning 17 has been added, which can provide additional load-bearing capacity for the bridge 1. Each module 2 may be provided with attachment or engagement means for securing the underspanning structure 17 to the lower chord member of the module.
FIG. 4 shows an example of how the road bridge span of FIG. 1 may be launched using a conventional “beak” or “nose” 18 and stand 19 to support a distal end of the bridge span 1′ as the latter is propelled across the space to be bridged. Three bridge beam modules 2 are shown already joined to each other (upper chord members 6 abutted, lower chord members 7 connected with ties 9), and a fourth bridge beam module 2′ is positioned on rollers 15 by crane 16, ready for connecting the part-assembled simple-beam span 1′. Using this method, successive bridge beam modules 2 can be added to the rear of the simple-beam bridge span 1′ as it is propelled out across the space to be spanned.
FIG. 5 shows an example of a truss arrangement which can be used to transmit shear stress between the plane 34 (indicated by dashed lines) of the upper chord member 6 of a bridge beam module 2 and the plane 35 (indicated by dashed lines) of its lower chord member 7. The planes 34 and 35 are substantially parallel and horizontal. In this example, four truss planes are shown. Two inner truss planes 32, shown with heavy lines for clarity, are arranged substantially vertically and perpendicular to the planes 34 and 35 of the upper and lower chords which comprise the simple-beam structure of the module. Two outer or lateral truss planes 30 are inclined at an angle to the vertical so as to enable the upper chord member 6 of the module 2 to be implemented with a significantly greater width than its lower chord member 7, while still ensuring the transmission of load from the lateral regions of the wider, upper chord member 6 to the narrower lower chord member 7. The inner truss planes 32 are shown comprising truss brace elements 33, while the outer truss planes are shown comprising angled truss brace elements 31.
FIG. 6 shows the truss plane arrangement of FIG. 5 in relation to the upper chord member (road deck) 6 and the lower chord member 7 of the bridge beam module 2. The road deck 6 comprises a central or medial road deck portion 6M and two lateral road deck portions 6L, one on either side of the medial road deck portion 6M. As will be described below, the lateral road deck portions 6L are hinged to the medial road deck portion 6M by hinges 14 so that they can be folded down out of the plane 34 of the upper chord when the bridge beam module is in its transport configuration. The medial road deck portion 6M is supported on the truss brace elements 33 of the two inner truss planes 32. Each of the lateral road deck portions is supported by the truss brace elements 31 of the angled truss plane 30 at or near its outer edge, and by the hinge 14 at its inner edge. In order to allow the lateral road deck portions to fold down for transport, the truss brace elements 31 may be provided with articulation means (illustrated symbolically in FIG. 6 with black dots 36). Note that lower chord member 7 is shown in FIG. 6 as a single contiguous block. In fact the structure of the lower chord member 7 may be an open braced structure or any other suitable structure. It may comprise two lateral girders braced together with diagonal bracing elements, for example. In such a case, the ends of the lateral girders can be provided with connection points or holes for connecting the ties 9 mentioned above. The lateral girders can also serve as rails for engaging with rollers or wheels over which the bridge beam modules 2 and/or the bridge spans 1 are launched.
FIGS. 7 to 10 show an example implementation of a road module 2. The medial and lateral road deck portions are shown strengthened with ribs or similar reinforcing structures 25, and each of the truss brace elements 31 is provided with three articulation axes 38, 36 and 37 which allow the truss brace element 31 to fold back on itself when the lateral road deck portion 6L is rotated down from its deployed state (as shown in FIGS. 7 and 9) to its retracted state (as shown in FIGS. 8 and 10). Note that in FIG. 10 the folded-down lateral road deck portion 6L has been rendered invisible (dashed line) in order to permit a side view of the folded truss brace elements 31 which would otherwise be obscured by the folded-down lateral road deck portion 6L. Each truss brace element 31 is shown comprising a first part 311, articulated to the lower chord member 7 at first articulation joint 38, a second part 312 extending between the first articulation joint 38 and a second articulation joint 37, and a third part 313, extending from a fixing 26 on the underside of the lateral road deck portion 6L to the second articulation joint 37. The three articulation axes 38, 36 and 37 are parallel and horizontal (i.e. parallel to a longitudinal axis of the bridge beam module 2) so as to allow the required articulation of the truss brace element 31. As shown in FIGS. 8 and 10, the articulation is arranged such that the folded truss brace elements 31 do not interfere with the (fixed) truss brace elements 33 of the inner truss planes 32. Also visible in FIGS. 9 and 10 are connection points 27 for attaching the ties 9 mentioned above. The articulations may be provided with locking or blocking means (not shown) for ensuring that the truss brace elements 31 remain straight and strong when the lateral road deck portions 6L are in their deployed state.
FIGS. 7 to 10 also show (dashed lines 21) the outline dimensions 22, 23, 24 (width 22, height 23, length 24) of a rectangular cuboid shape which has the dimensions of a standard freight container. In fact the length of the road deck 6 can be slightly smaller than the corresponding standard length of a standard freight container. Standard container type lash fittings can be integrated (or fitted, for example using adapter elements) to the road deck 6 and the lower chord member 7. Such container fittings are not illustrated in the figures.
Also indicated in FIG. 9 are the thickened end portions 40 of the medial and lateral portions of the road deck 6. The road deck 6 may be constructed of steel plate having a thickness of 8 mm to 15 mm (typically 11 mm), for example, the ends of the road deck 6 may be strengthened where they abut the road deck 6 of the next bridge beam module 2. The thickened portions 40 may be 40 mm to 60 mm thick, for example, and will be described in more detail with reference to FIGS. 11 to 15.
FIG. 11 shows a simplified cross-section illustration of a contact zone 41 between the ends 40 of two abutting upper chord members (road decks 6) of a simple-beam bridge span 1, illustrating an elastic deformation zone 44 of steel in the vicinity of the contact zone. The abutting end regions 40 of the upper chord member 6 (road deck) are machined with a chamfer 45 or otherwise shaped such that the contact faces 41 have a contact height 42 which is substantially less high than the thickness 43 of the thickened end region 40 of the road deck 8. Thus, for example, the end region 40 may have a thickness 43 of 30 mm to 60 mm, while the contact face 41 has a height 43 of 5 mm to 20 mm or more preferably 10 to 15 mm. This relatively small snug-fitting contact surface means that the steel in the regions 44 adjacent to the contact surfaces 41 can deform elastically so as to allow a homogeneous distribution of stress transmission between neighboring road decks 6. It also allows for a modest amount of angular movement between adjacent road decks 6 which may be useful during assembly. It can also reduce work-hardening effects at the abutting junction between road decks 6 of adjacent simple beam bridge spans 1, which may otherwise arise due to repeated loading and recovery cycles when the bridge is in use. Each simple-beam bridge span will bend under load, so a load traveling across the bridge will give rise to angular movement between the road deck ends of end modules 2 adjacent bridge spans 1.
FIG. 12 shows a coupling arrangement for holding two adjacent road deck ends 40 together to prevent or resist any axial parting motion of the two road deck ends. A simple fishplate arrangement 46 may be used, for example, with bolts or lugs 47 which engage with corresponding holes in the thickened end 40 of the road deck end.
Shear forces can be transmitted between the abutting ends 40 of two road decks 6 by simple friction (for example by a suitable shaping of the road deck ends) and/or by means of dowels 48 as shown in FIG. 13. The dowel 48 may be fixed to the left-hand road deck end 40 of FIG. 13, for example, and engage with a corresponding female engagement location 49 of the right-hand road deck end 40. This engagement arrangement may also serve to prevent or resist transverse movement of the road decks ends 40 relative to each other across the plane 35 of the road deck 6. The engagement arrangement (e.g. dowel) may also be tapered or otherwise shaped (as shown in FIG. 13) to help guide the positioning of the road deck ends 40 into their abutment configuration.
FIGS. 14 and 15 show a transom arrangement for supporting the road deck ends 40 of adjacent modules 2 at the junction between two simple-beam bridge spans 1. In this case, the ends 40 of the road decks rest on a load transfer block 50 of a transom 11. An axial retention plate 46′, which may be secured to the transom 11, prevents axial parting of the road deck ends 40. The transfer block 50 advantageously has a curved upper surface so that the contact area between the three contacting elements 40, 40, 50 is kept small, such that the contact zone 41 can accommodate modest movement between the three contacting elements without any significant surface friction.
FIG. 16 shows in plan elevation a schematic view from below of the ends of two upper chord members (road deck ends), illustrating a reversible locating dowel arrangement and a corresponding transom arrangement. The bridge beam modules 2 are configured such that they can be fitted end-to-end with other similar bridge beam modules, irrespective of which way round the module is. FIG. 16 shows an example of how the dowel engagement arrangement (and, in the case of an inter-span connection, a transom 11) can be configured in order to achieve such a reversible connectability. The reversibility of the modules may be understood as a rotational symmetry of the abutment connections about an orthogonal (i.e. vertical) axis passing through a central point of the road deck plane of the module.
Patent Application
20160289904
