Building construction method and system

Abstract

A building system that includes a plurality of screw piles ( 34, 36 ) positioned in the ground and one or more perimeter beams ( 16 ), wherein at least part of the perimeter beam ( 16 ) has a sloped lower surface ( 66, 68 ). The sloped lower surface of the perimeter beams ( 16 ) can divert swelling soils away from the perimeter beam ( 16 ). The swelling soils can be diverted into voids.

1 . A building system, characterised in that the building system includes a plurality of screw piles positioned in the ground and one or more perimeter beams, wherein the perimeter beams have a lower surface adapted to cleave swelling soil. 
     
     
         2 . A building system as claimed in  claim 1  wherein the lower surface of the perimeter beam is further adapted to divert swelling soil away from the perimeter beam. 
     
     
         3 . A building system as claimed in  claim 1  wherein the lower surface of the perimeter beams comprises a single sloped lower surface or two sloped lower surfaces. 
     
     
         4 . A building system as claimed in  claim 3  wherein at least one of the perimeter beams has a generally V-shaped lower surface when viewed in cross-section or the lower surface of at least one of the perimeter beams comprises a first region extending at a first angle and a second region extending at a different angle. 
     
     
         5 . A building system as claimed in  claim 1  wherein the perimeter beams are positioned on or above the screw piles, or the perimeter beams rest on the screw piles, or the perimeter beams rest on one or more supports or cradles positioned on the screw piles, or the perimeter beams extend around an upper portion of the screw piles and extend above the top of the screw piles. 
     
     
         6 . A building system as claimed in  claim 1  comprising a plurality of precast perimeter beams being positioned above the screw piles. 
     
     
         7 . A building system as claimed in  claim 6  wherein the perimeter beams are supported on one or more supports or cradles positioned on the screw piles and the supports or cradles have a support surface that is complementary in shape to a lower surface of the perimeter beams. 
     
     
         8 . A building system as claimed in  claim 7  wherein the perimeter beams are tied to the supports or cradles. 
     
     
         9 . A building system as claimed in  claim 6  wherein the perimeter beams are tied to pile caps positioned on the upper part of the screw piles. 
     
     
         10 . A building system as claimed in  claim 8  wherein the supports or cradles are provided with one or more shims or adjusting plates to alter or adjust the height of the perimeter beam relative to the top of the screw pile. 
     
     
         11 . A building system as claimed in  claim 10  wherein the one or more shims or adjusting plates comprise angled plates or V-shaped plates. 
     
     
         12 . A building system as claimed in  claim 1  wherein the building system comprises a plurality of screw piles positioned in the ground and a slab constructed on and formed generally above the screw piles, the slab including a perimeter beam, characterised in that at least part of the perimeter beam has a sloped lower surface. 
     
     
         13 . A building system as claimed in  claim 12  wherein the slab includes one or more void formers, and the sloped lower surface of the perimeter beam diverts swelling soil to a region occupied by the one or more void formers. 
     
     
         14 . A building system as claimed in  claim 13  wherein the one or more void formers comprise void formers that are designed to be crushed when subjected to pressure from swelling soils under the slab. 
     
     
         15 . A building system as claimed in  claim 14  wherein the one or more void formers comprise void formers that are designed to crush in a predetermined direction and height when subjected to hydraulic uplift pressures from heaving clay soils under the slab. 
     
     
         16 . A building system as claimed in  claim 15  wherein the perimeter beam is formed by setting out appropriate formwork, positioning the void formers, laying reinforcement and pouring concrete so that it covers the void formers to a predetermined depth to form a continuous upper concrete surface of the slab) and extend around the void formers to form the perimeter beam. 
     
     
         17 . A building system as claimed in  claim 16  wherein the slab includes other beams. 
     
     
         18 . A building system as claimed in  claim 17  wherein the other beam or beams also have a sloped lower surface. 
     
     
         19 . A building system as claimed in  claim 12  wherein the sloped lower surface of the beams is formed by appropriately shaping the ground in the vicinity of the beams and pouring concrete on to the appropriately shaped ground, or by using a appropriate forming element. 
     
     
         20 . A building system as claimed in  claim 19  wherein the beam has a generally V-shaped lower surface and a generally V-shaped forming is placed in the vicinity of beams and concrete subsequently poured into the forming member to form the lower surface of the beams. 
     
     
         21 . A building system as claimed in  claim 20  wherein the generally V-shaped forming member comprises a generally V-shaped metal sheet or plastic sheet. 
     
     
         22 . A building system as claimed in  claim 3  wherein the sloped lower surface of the beams slopes upwardly at an angle of between at least 20° to 45°. 
     
     
         23 . A building system as claimed in  claim 1  wherein each screw pile is fitted with a pile cap such that a structural slip joint is formed between the pile cap and the slab. 
     
     
         24 . A method for constructing a building slab comprising the steps of positioning a plurality of screw piles in the ground, and forming a concrete slab above the screw piles, the concrete slab having a perimeter beam, wherein at least part of the perimeter beam's lower surface-is adapted to cleave swelling soil. 
     
     
         25 . A method as claimed in  claim 24  wherein the perimeter beam has two sloped lower surfaces. 
     
     
         26 . A method as claimed in  claim 25  wherein the two sloped lower surfaces comprise a V-shaped lower surface when viewed in cross-section along the beam. 
     
     
         27 . A method as claimed in  claim 26  further comprising the step of placing pile caps on each of the screw piles prior to forming the concrete slab. 
     
     
         28 . A method as claimed in  claim 27  further comprising the step of positioning slope formers for forming the sloped lower surfaces of the beam prior to forming the concrete slab. 
     
     
         29 . A method as claimed in  claim 28  wherein the slope formers comprise V-shaped sheets or members. 
     
     
         30 . A method as claimed in  claim 29  wherein the slope formers are positioned over one or more of the screw piles. 
     
     
         31 . A method as claimed in  claim 30  wherein holes are formed in the slope formers and the slope formers are positioned by placing the holes over the screw piles and sliding the slope formers down along the shaft of the screw pile. 
     
     
         32 . A method as claimed in  claim 31  wherein pile caps may then be placed onto the one or more screw piles that have the slope formers positioned thereon. 
     
     
         33 . A method as claimed in  claim 32  further comprising the step of positioning one or more void formers prior to forming the concrete slab. 
     
     
         34 . A method as claimed in  claim 33  wherein the one or more void formers comprise crushable void formers. 
     
     
         35 . A method as claimed in  claim 34  wherein, in the finished slab, the one or more void formers are positioned under the slab and interiorly of the perimeter beam. 
     
     
         36 - 43 . (canceled)