Structural module

Abstract

A sub-base layer for use in construction, comprises a plurality of connected substantially cuboid modules each having spaced-apart, substantially parallel top and bottom walls joined by a peripheral sidewall defining an enclosed volume. The connection between the modules is effected by a plurality of tie members which prevent lateral movement of the modules relative to one another. The layer is particularly useful as a lightweight replacement for aggregate sub-base layers in foundations, roadways, pavement, carparks, and the like.

1 . A sub-base layer for use in construction, said layer comprising a plurality of connected, substantially cuboid modules each comprising spaced-apart, substantially parallel top and bottom walls joined by a peripheral sidewall defining an enclosed volume, the connection between said modules being effected by a plurality of tie members which prevent lateral movement of the modules relative to one another.  
     
     
         2 . A sub-base layer according to  claim 1 , wherein each module is formed from a top half which includes said top wall and the upper part of said peripheral sidewall, and a bottom half defining said bottom wall and the lower part of said peripheral sidewall.  
     
     
         3 . A sub-base layer according to  claim 2 , wherein the top and bottom halves are each provided with a set of half-pillars extending within the enclosed volume towards one another, whereby the two sets of half-pillars co-operate with one another to form pillars extending between the top and bottom walls to resist vertical crushing of the module.  
     
     
         4 . A sub-base layer according to  claim 2  or  3 , wherein the top and bottom halves are two substantially identical integral plastics moulded components which are fitted one inverted on top of the other.  
     
     
         5 . A sub-base layer according to any preceding claims, wherein the height of the peripheral sidewalls is substantially less than both the width and the length of the top and bottom walls.  
     
     
         6 . A sub-base layer according to any preceding claims, wherein each module further comprises a network of bracing members extending between the pillars within said enclosed volume to resist geometric deformation of said module in a horizontal plane.  
     
     
         7 . A sub-base layer according to  claim 6 , wherein said sidewall and said network are apertured to allow fluid flow both vertically and horizontally through said module.  
     
     
         8 . A sub-base layer according to any preceding claim, further comprising an infill medium disposed within the enclosed volume of one or more of said modules.  
     
     
         9 . A sub-base layer according to  claim 8 , wherein said infill medium is a medium which provides biological and/or chemical treatment of water stored in or passing through the modules.  
     
     
         10 . A sub-base layer according to any preceding claims, wherein said tie members are adapted to clamp together abutting sidewalls of a pair of adjacent modules.  
     
     
         11 . A sub-base layer according to  claim 10 , wherein the peripheral sidewall of each module is provided with a keyway for receiving one half of a tie member.  
     
     
         12 . A sub-base layer according to  claim 11 , wherein said keyway is in the form of a female dovetail groove extending through the height of the sidewall.  
     
     
         13 . A sub-base layer according to  claim 12 , wherein each tie member is an elongate member having a cross sectional outline of a pair of adjoined symmetrically identical trapezoids connected along the shorter of their parallel sides.  
     
     
         14 . A sub-base layer according to  claim 13 , wherein an elongate reinforcing member is disposed within the interior of the tie member.  
     
     
         15 . A sub-base structure comprising at least two sub-base layers according to any preceding claim, said layers being disposed one above the other, and a plurality of reinforcing struts connected between the layers.  
     
     
         16 . A sub-base structure according to  claim 15 , wherein each strut is hollow to provide a fluid passageway through the strut.  
     
     
         17 . A sub-base structure according to  claim 16 , wherein said struts extend between opposed surfaces of two sub-base layers, and wherein said opposed surfaces are provided with formations to engage the struts and retain them in position relative to the modules.  
     
     
         18 . A sub-base structure according to  claim 17 , wherein said opposed faces of the modules are provided with fluid ports in the vicinity of the struts whereby the enclosed volumes in the two levels are in communication via the interior of the hollow struts.  
     
     
         19 . A sub-base structure according to  claim 17  or  18 , wherein each strut is in the form of a hollow cylinder having a central support post and a plurality of planar supports extending radially between the support post and the internal surface of the cylinder.  
     
     
         20 . A sub-base structure according to any one of claims  15 - 19 , wherein said at least two sub-base layers define upper and lower faces of a cage structure having an internal space in which said struts are located, and further comprising one or more side modules disposed perpendicular to the modules in said layers and extending between said upper and lower faces at the periphery of said layers, whereby said side modules define at least a part of a side of said cage structure.  
     
     
         21 . A sub-base structure according to any preceding claims, wherein one or more surfaces of the modules are at least partially covered by a geomembrane or geotextile.  
     
     
         22 . A structural module comprising spaced-apart, substantially parallel top and bottom walls joined by a peripheral sidewall defining an enclosed volume, a plurality of pillars extending within said enclosed volume substantially vertically between the top and bottom walls to resist vertical crushing of the module, and a network of bracing members extending between the pillars within said enclosed volume to resist geometric deformation of said module in a horizontal plane, said top and bottom walls, said sidewall and said network being apertured to allow fluid flow both vertically and horizontally through said module.  
     
     
         23 . A module according to  claim 22 , wherein the geometrical shape of the module is such that a plurality of such modules may be disposed closely adjacent one another along their sidewalls to form an extensive, substantially continuous layer of modules, the module further including means for rigid connection of said module to adjacent modules in said continuous layer.  
     
     
         24 . A module according to  claim 22  or  23 , wherein the module is made of two substantially identical integral plastics moulded components which are fitted one inverted on top of the other.  
     
     
         25 . A module according to any one of claims  22 - 24 , further comprising an infill medium disposed within the enclosed volume  
     
     
         26 . A module according to  claim 25 , wherein said infill medium is a medium which provides biological and/or chemical treatment of water stored in or passing through the modules.  
     
     
         27 . A module according to  claim 23 , wherein said means for rigid connection comprises a keyway in said peripheral sidewall for receiving one half of a tie member.  
     
     
         28 . A module according to  claim 27 , wherein said keyway is in the form of a female dovetail groove extending through the height of the sidewall.  
     
     
         29 . A module according to  claim 27  or  28 , wherein said keyway is tapered along its length to provide a progressively tighter fit for said tie member as it moved into the keyway.  
     
     
         30 . A tie member for connecting a pair of structural modules, said tie member comprising an elongate member having a substantially constant cross sectional outline of a pair of adjoined symmetrically identical trapezoids connected along the shorter of their parallel sides.  
     
     
         31 . A sub-base layer according to  claim 30 , wherein an elongate reinforcing member is disposed within the interior of the tie member.