GB664854A - A method and an equipment for the making of piles of concrete in situ - Google Patents

Abstract

664,854. Piles. SVENSKA ENTREPRENDL AKTIEBOLAGET. May 17, 1949. [Oct. 21, 1948] No. 13170/49. Class 68 (ii). In the casting of concrete piles in situ, a tube 10 temporarily closed at its lower end by a pile point 27 is driven into the ground and concrete is supplied to the inside of the tube 10 through a tube 12 forming part of an assembly which is housed in the tube 10 but is substantially or entirely disconnected therefrom so that the shocks of the driving are not communicated to the assembly. The assembly consists of the tube 12 and a conical lower end which is welded to a ring 13 having a groove to accommodate a rubber sealing ring 15. The ring 13 defines a lower chamber 35 into which the concrete is received, the superincumbent concrete in the tube 12 producing a pressure in the concrete which tends to lift the ring 13 and associated parts. The tube 12 supports, by welded spiders 17, a number of tubes 16 which pass into holes in the ring 13 and serve to position reinforcement rods during the casting of the pile. The rods are dropped through the tubes 16, the ends, which are suitably tapered, jamming in the tapered annular groove 30 in the pile point 27. Rubber sleeves 20 depend from tubes 18 aligned with the tubes 16 and seal against the rods to prevent the upward leakage of concrete. Arms 22 project from the upper end of the tube 12 and are slidably arranged in slits 23 in the tube 10, the assembly being supported for raising and lowering as necessary by a sleeve 24 slidable on the outside of the tube 10 and having radial arms 25 for connection to the lifting wires 26. The tube 10 is first driven into the ground by a weight 34, a wooden impact pad 32 resting on a steel plate 31 to protect the end of the tube. When driving is finished, the assembly is lowered fully and the reinforcement rods 21 are dropped in. The assembly is then lifted to the extent permitted by the slots 23, a protective cover 36 is applied and concrete is supplied to the tube 12 by an eccentrically arranged hopper tube 39. When the concrete fills the tube to the level producing the desired pressure in the chamber 35, the tube 10 is pulled up slowly by the wires 26, more concrete is supplied from the hopper 41 and the tube is again pulled up progressively. A float in the tube 12 is connected by a wire to a scale to give an indication of the conditions in the tube and pile. During the extraction of the tube 10 it may be vibrated to consolidate the concrete. In a modification, the assembly is suppotted by spring means in the tube 10 which lessen the effect of the blows on the assembly. A ring is welded to the tube 12 at a little distance below its top, springs above the ring being compressed as the assembly rises, whilst springs below the ring are compressed as the assembly falls. The springs are threaded on bolts depending from a ring which is detachably secured in the top of the tube 10, this ring being spaced from the impact pad 31 by a rubber or like cushion.