Road-bridge module and bridge construction method

Abstract

A bridge module is described which, when in its retracted configuration, is shaped and dimensioned as a standard ISO container, and which, when in its deployed configuration, can be secured end-to-end with other similar modules to form a simple-beam bridge span having a substantially trapezoidal cross-section. The module comprises a road deck which forms the upper chord of the simple beam structure and a lower chord. The shear loading in the simple beam structure is transmitted between the upper and lower chords by means of parallel inner truss elements and angled outer truss elements. The road deck comprises a medial road deck portion and two lateral road deck portions which are hinged at to fold down into a retracted configuration for transport. The angled outer truss elements may be articulated to permit this retraction and to facilitate deployment. In its retracted state, the bridge module fits within a rectangular cuboid.

1 . A longitudinal bridge beam module configured for being abutted end-to-end with one or more similar bridge beam modules to form a simple beam road bridge span suspended or supported at end-points of the road bridge span so as to support a vertical load on the road bridge span, wherein:
 the bridge beam module comprises a longitudinal upper beam chord member and a longitudinal lower beam chord member;   the upper beam chord member comprises a road deck extending in a road deck plane along the length of the bridge beam module;   the upper beam chord member comprises a medial road deck portion extending in the road deck plane along the length of the bridge beam module, and first and second lateral road deck portions, each of which lateral road deck portions extends along the length of the bridge beam module;   the bridge beam module comprises displacement means for displacing the first and second lateral road deck portions of the upper beam chord member between a deployed configuration and a retracted configuration of the bridge beam module;   in the deployed configuration, the said first and/or second lateral road deck portions are substantially coplanar with and adjacent to the medial road deck portion; and   in the retracted configuration, the bridge beam module has a substantially cuboidal shape of between  2 .4 m and 2.5 m in width and between 2.5 m and 2.6 m or 2.9 m in height, the medial road deck portion forming an upper surface of the cuboidal shape and each of the first and second lateral road deck portions forming at least a part of a longitudinal side wall of the cuboidal shape.   
     
     
         2 . The bridge beam module according to  claim 1 , wherein the displacement means comprise rotation or hinge means for rotating the lateral road deck portions between the deployed and retracted configurations. 
     
     
         3 . The bridge beam module according to  claim 2 , wherein the rotation or hinge means are configured for a rotation of the lateral road deck portions through substantially 90 degrees. 
     
     
         4 . The bridge beam module according to  claim 1 , comprising shear truss members for transmitting shear load between the upper and lower beam chord members. 
     
     
         5 . The bridge beam module according to  claim 4 , comprising angled shear truss members configured to support the lateral road deck portions when in the deployed configuration, wherein the angled shear truss members comprise retraction means for retracting the angled shear truss members within the rectangular cuboid when in the retracted configuration. 
     
     
         6 . The bridge beam module according to  claim 5 , wherein the retraction means comprises a plurality of articulation joints. 
     
     
         7 . The bridge beam module according to  claim 6 , wherein the articulation joints are arranged such that the shear truss members fold into the volume of the rectangular cuboid. 
     
     
         8 . The bridge beam module according to  claim 1 , wherein:
 the medial and lateral road deck portions have a first thickness over a majority of an area in the road deck plane;   the medial and lateral road deck portions each comprise thickened end regions each having a second thickness, greater than the first thickness;   each of the end regions comprises a contact face for providing an abutting contact with an end region of the said similar bridge beam module, wherein the contact end region has a height which is smaller than the second thickness.   
     
     
         9 . The bridge beam module according to  claim 8 , wherein the first thickness is between 8 mm and 15 mm, or more preferably between 10 mm and 12 mm, the second thickness is at least 20 mm, and the height of the contact face is between 5 mm and 20 mm, or more preferably between 10 mm and 15 mm. 
     
     
         10 . The bridge beam module according to  claim 1 , comprising a tie element for linking the lower chord member to the lower chord member of the said similar bridge beam module. 
     
     
         11 . The bridge beam module according to  claim 1 , comprising a container lift engagement element located substantially at each of the vertices of the rectangular cuboid. 
     
     
         12 . The bridge beam module according to  claim 1 , having a length substantially equal to 10 ft, 20 ft, 30 ft or 40 ft. 
     
     
         13 . The bridge beam module according to  claim 1 , configured to be reversibly abuttable to the said similar bridge beam module. 
     
     
         14 . A simple-beam bridge span comprising two or more bridge beam modules according to  claim 1 , wherein the two or more bridge beam modules are abutted and tied end-to-end. 
     
     
         15 . The simple-beam bridge span of  claim 14 , wherein the lower chord members of the two or more bridge beam modules are provided with securing points for securing an underspanning structure of the simple-beam bridge span. 
     
     
         16 . A bridge comprising a first simple-beam bridge span according to  claim 14  and a second simple-beam bridge span according to  claim 14 , wherein an outer lateral edge of a first lateral road deck of the first simple-beam bridge span abuts an outer edge of a second lateral road deck of the second simple-beam bridge span to form a substantially continuous planar road deck having a width substantially equal to the sum of the widths of the road decks of the first and second simple-beam bridge spans. 
     
     
         17 . A method of constructing a road bridge comprising the steps of:
 providing a first and a second bridge beam module according to  claim 1 ;   displacing the first and second lateral road deck portions of each of the first and second bridge beam modules from the retracted configuration to the deployed configuration;   abutting an end of the upper beam chord member of the first bridge beam module to an end of the upper beam chord member of the second bridge beam module such that the first and second upper beam chord members are substantially co-planar, and such that a compression load in one of the first or second upper beam chord members is transferred axially to the other; and   securing an end of the lower beam chord member of the first bridge beam module to an end of the lower beam chord member of the second bridge beam module such that a tension load in one of the first or second lower beam chord members is transferred axially to the other.   
     
     
         18 . The method according to  claim 17 , further comprising the step of securing a common underspanning structure to securing points of the lower beam chord members of the first and second bridge beam modules.