P/00/0 12 Regulation 3.2 AUSTRALIA Patents Act 1990 ORIGINAL COMPLETE SPECIFICATION INNOVATION PATENT Invention Title: "RAPID LOAD CAPACITY TEST" The following statement is a full description of this invention, including the best method of performing it known to me/us: 1 TITLE: RAPID LOAD CAPACITY TEST BACKGROUND OF THE INVENTION: 1. Field of the invention: 5 [0001] This invention relates to a rapid load capacity test. [0002] The invention relates, but is not limited to, a load capacity test for the foundations of buildings; and more particularly, to the load capacity of piers or piles supporting the foundations. [0003] Through out the specification, the term "piles" will be used to 10 include both piers or piles, whether driven into the ground (e.g. by a pile driving machine), screwed into the ground, or cast in-situ. 2. Prior art: [0004] Piles, having (typically hollow) steel shafts, are used to support building constructions, more typically building slabs, and are screw-driven 15 into the soils below the slabs to be constructed. [0005] Screw piles have at least one helical screw- or flyte around the shafts, usually adjacent the digging point at the lower end of the shafts. The helical screws- or flytes may be provided at spaced locations along the shafts, to spread the load transfer from the piles to the surrounding 20 soil. [0006] Engineers are always concerned that the load-bearing strength of the piles is sufficient to support the building constructions, in both static and dynamic-load conditions. In cyclonic areas, wind forces can apply both lateral and vertical-uplift loads on a building construction, and so the 25 load-bearing strength of the piles is not the only factor to be taken into account when specifying the piles and their locations under the building. [0007] To enable the engineers to establish the load bearing capacity of the piles at a particular site, they typically have at least one test hole drilled to determine the soil profile and load capacity. However, as the soil 30 structure may markedly vary within 30 cm (or less) of the test hole e.g. with an increased sand or clay content, the engineer must assume the soil structure is uniform over the site. 13900791 S:\NrPortbl\FAKDocs\GADAMS\1 390079_1.DOC 2 [0008] As structural failure is a greater concern than structural cost to the engineer, the resultant specification of the piles, and their location, is likely to be much greater than is necessary to achieve the desired load bearing capacity. 5 [0009] Alternatively, if the test hole indicated the soil structure is stronger / more stable than the remainder of the site, the "over-specification" based in the test hole may actually result in "under-specification" for the balance of the site. [0010] Many geographical areas in Australia, including Adelaide, have 10 reactive soils, typically containing an high clay content. It is not unknown for such reactive soils to be liable to vertical "heave" exceeding 30cm between fully dry and fully wet. [0011] The 'heave" of the reactive soils has resulted in damage to building foundations, and to vertical displacement of a building relative to adjacent 15 facilities / utilities. [0012] It has been known, however, that the "heave" of the reactive soils e.g. following rain after a long period of drought, has been so large as to raise the piles in the soil. 20 OBJECTS OF THE PRESENT INVENTION: [0013] It is an object of the present invention to overcome, or at least ameliorate, the problems of the prior art. [0014] Other preferred objects will become apparent from the following description. 25 SUMMARY OF THE PRESENT INVENTION: [0015] In one aspect, the present invention resides in a method for testing the load-bearing capacity of piles driven into the ground, the method including the steps of: 30 a) placing a load capacity test rig adjacent a pile driven into the ground; b) connecting a load-applicator on the test rig to the pile; c) applying an up-lifting load to the pile by the load-applicator; 1390079_1 S:NrPortbl\FAKDocs\GADAMS\1 390079_1.Doc 3 d) measuring the up-lifting load; and e) calculating the load-bearing capacity of the pile from the up-lifting load. [0016] Typically, the measured up-lifting load will be approximately 70% of the calculated load-bearing capacity of the pile. 5 [0017] In a second aspect, the present invention resides in apparatus for testing the load-bearing capacity of piles driven into the ground, the apparatus including: a test rig having a frame supportable on the ground adjacent the pile to be tested; 10 a load-applicator on the frame; a connection apparatus to connect the load-applicator to the pile; and measuring and/or indication apparatus to measure an up-lifting load applied to the pile by the load-applicator and/or to calculate, or to indicate, the load-capacity of the pile. 15 [0018] Preferably, the frame has a base supportable on the ground; and the frame substantially surrounds a shaft of the pile to be tested. [0019] Preferably, the load-applicator is a hollow ram hydraulic jack. Alternatively, the load-applicator includes hydraulic jack(s), pneumatic jack(s), mechanical screw jack(s), or the like, mounted on the frame; 20 where the jack(s) may be operably connected to a lifting-head, lifting yoke, or the like. [0020] Preferably, the connection apparatus includes at least one lifting rod or bar connected to the load-applicator at an upper end of the at least one lifting rod or bar; and 25 a lower end of the at least one lifting rod or bar is releasably coupled to the shaft of the pile, at or adjacent the upper end of the shaft. [0021] Preferably, the at least one lifting rod or bar is coupled to the shaft by a screw-threaded connection, a bayonet-type connection, a wedge type connection; or the like. 30 [0022] Preferably, the measuring and/or indication apparatus includes a sensor to measure the hydraulic pressure applied to the load-applicator, the gauge or indicator connected to the sensor indicating the hydraulic 1390079_1 S:NrPortbI\FAKDocs\GADAMS\1 390079_1.DOC 4 pressure, the measured up-lift force applied to the pile and/or the calculated load-bearing capacity of the pile. BRIEF DESCRIPTION OF THE DRAWING: 5 [0023] To enable the skilled workman to fully understand the invention, and to enable that person to put the invention into practice, preferred embodiments will now be described with reference to the accompanying drawing, in which: FIG. 1 is a schematic side view of the testing of a blade pile in accordance 10 with a first embodiment of the present invention. [0024] Any annotations on FIG. 1 are by way of illustration only, and are not limiting to the scope of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS: 15 [0025] The blade pile 10 schematically illustrated in FIG. 1 is representative of all screw- or blade piles, where a hollow steel shaft 11 is terminated at a digging point or tip 12, and one or more pairs of screws or blades 13 are provided on the shaft. The skilled addressee will be aware that the pairs of screws or blades 13 may be provided at spaced intervals 20 up the shaft 11; and that stabilising fins (not shown) may be provided about the shaft 11 to increase the lateral stability of the pile 10. [0026] A load-bearing capacity test apparatus 20, to test the load-bearing capacity of the pile 10, has a transportable test rig 30 which can be moved from pile to pile 10 to be tested on-site. 25 [0027] The test rig 30 has a frame 31, with a substantially annular base plate, or feet 32, at the lower end of a plurality of spaced steel struts 33, which support a substantially annular pad 34 at their upper ends. The base plate, or feet 32, are arranged to enable the test rig 30 to be slid laterally into co-axial alignment with the pile shaft 11. 30 [0028] A hollow hydraulic ram jack 40 is mounted co-axially on the annular pad 34. The ram jack 40 is connected to a (high-pressure) hydraulic pump 50 via hydraulic hoses 51, 52 and pressure gauge 53. 13900791 S\NrPortb\FAKDocs\GADAMS\1 390079_1.DOC 5 [0029] The hydraulic ram jack 40 has an annular cylinder 41 and an annular piston rod 42. [0030] A lifting rod 60 is received co-axially within a central passage 43 through the piston rod 42 (and cylinder 41 ). The lifting rod 60 is screw 5 threaded at least at its respective upper and lower ends 61, 62. [0031] The upper end 61 of the lifting rod 60 is secured to the distal end of the piston rod 42 by an abutment washer 63 and high tensile nut 64. [0032] The lower end 62 of the lifting rod 60 is connected to the upper end 14 of the pile shaft 11 by a releasable coupling apparatus 70. 10 [0033] In the embodiment illustrated in FIG. 1, the coupling apparatus 70 includes a screw-threaded nut insert 71 secured in the upper end 14 of the pile shaft 11. [0034] In an alternative embodiment, not shown, lugs or fingers may be provide on the exterior of the upper end 14 of the pile shaft 11, or 15 internally in the upper end 14 of the pile shaft 11, and be releasably engaged by a complementary bayonet-type coupling at the lower end 62 of the lifting rod 60; or vice versa. [0035] In other alternative embodiments, one or more transverse locking pins may releasably connect the lower end 62 of the lifting rod 60 to the 20 upper end 14 of the pile shaft 11; the lifting rod 60 and pile shaft 11 may be screw-threadably coupled together; or a wedge-type connection e.g. with balls or rollers in an annular coupling head, may couple the lifting rod 60 and the pile shaft 11. [0036] The skilled addressee will appreciate that there are many possible 25 releasable coupling methods to connect the lifting rod 60 to the pile shaft 11. [0037] The skilled addressee will also appreciate that the hollow hydraulic ram jack 40 may be substituted by one or more hydraulic-, pneumatic- or mechanical screw jack(s), which may be connected to the upper end 61 of 30 the lifting rod 60 by a lifting-head, lifting-yoke or like device to spread the load between the jacks. [0038] The skilled addressee will further appreciate that two or more lifting 1390079_1 S:\NrPortbl\FAKDocs\GADAMS\1 390079_1.DoC 6 rods may interconnect the lifting-head, lifting-yoke or like device to a coupling apparatus connectable to the upper end 14 of the pile shaft 11. With this arrangement, it is preferable that the coupling apparatus be releasably connectable to the exterior of the pile shaft 11. 5 [0039] In a further alternative embodiment not illustrated, the lifting rod (or rods) may be connected to (e.g. the distal end of) a lever arm, or rocker arm, pivotally mounted on the frame 31 and selective raised by one or more jacks. [0040] In use, the test rig 30 is located with the lifting rod 60 co-axially 10 aligned with the pile shaft 11. The lower end 62 of the lifting rod 60 is coupled to the upper end 14 of the pile shaft 11 by screw-threaded engagement between the lower end 62 of the lifting rod 60 and the nut insert 71. [0041] The hydraulic pump 50 is operated to supply hydraulic fluid, of 15 increasing pressure, to the hydraulic lift jack 40, causing the piston rod 42 to apply a lifting load to the lifting rod 60, which transfers the lifting load to the pile shaft 11. [0042] The operator monitors the hydraulic pressure via the gauge 53, and can calculate the lifting force being applied to the pile 10. By use of 20 the conversion uplift-force = 70% (load-bearing capacity), the operator can calculate the load-bearing capacity of the pile 10. (The skilled addressee will appreciate that the gauge can be calibrated to directly indicate the uplift force applied to pile 10 and/or the load-bearing capacity of the pile 10; or that the hydraulic pressure may be measured by a 25 sensor, where the output is fed to a computer for calculation / display / recordal of the load-bearing capacity for each specific pile. [0043] The operator can either determine the absolute load-bearing capacity of the pile 10; or test to ensure the load-bearing capacity of the pile is within design limits e.g. 8 tonnes. 30 [0044] When the particular pile 10 has been tested, the hydraulic pressure is reduced and the test rig 30 is disconnected from the pile. It can now be easily moved about the site to test another selected pile 10. This means 1390079_1 S\NrPortbl\FAKDocs\GADAMS\1 390079_1.DOC 7 that several piles 0 can be quickly tested on a site to determine the soil structure(s) on the site, and their load-bearing characteristics. [0045] By use of the test method and apparatus of the present invention, the engineer can quickly, and accurately, establish the load-bearing 5 capabilities of the soil structures at multiple locations across a site, rather than simply relying on a single test result as representative of the whole site. This means that an engineer may be able to specify lighter construction piles and/or fewer piles to achieve the design load for the piles supporting the building construction. 10 [0046] In addition, if the testing method provides markedly varying measured load-bearing capacities, the engineer can immediately request that additional piles be tested e.g. in a location where the largest variations occur. The additional tests can be quickly, and relatively inexpensively, carried out. 15 [0047] The engineer is more confident that the foundation design, supported by the piles, is appropriate for the building construction, as changes in the soils structure / characteristics can be compensated for e.g. where the site covers both reactive and no-reactive soils. [0048] Various changes and modifications may be made to the 20 embodiments described and illustrated without departing from the present invention. 25 30 1390079_1 S\NrPortbl\FAKDocs\GADAMS\1 390079_1.DOC