Apparatus and method for slipforming a shaft

Abstract

The invention relates to a slipform apparatus (12, 14, 16) and method (50) of operating a slipform apparatus for constructing a primary slipform structure (22) from one side thereof. The slipform apparatus comprising a platform (12) having a plurality of work levels (28, 30, 32), and a lift device having at least one cable (14). The platform (12) is suitable for suspending from above by said cable (14) and the lift device is operable to raise or lower the platform (12). The plurality of work levels (28, 30, 32) are provided around a perimeter of the platform (12) and surround a central space (33) through the plurality of work levels (28, 30, 32). The method includes suspending the platform (12) from above using the lift device (14, 16), performing a rebar installation operation comprising raising the platform (12) using the lift device (14, 16) and installing at least one rebar cage (18, 20), using the lift device (14, 16) to lower the platform (12) to abase of the at least one rebar cage (18, 20), and performing a concrete slipform operation of the at least one rebar cage (18, 20) comprising raising the platform using the lift device (14, 16).

1 . A slipform apparatus for constructing a primary slipform structure from one side thereof, comprising a platform having a plurality of work levels, and a lift device having at least one cable, the platform being suitable for suspending from above by said at least one cable and the lift device being operable to raise or lower the platform, wherein the plurality of work levels are provided around a perimeter of the platform and surround a central space through the plurality of work levels. 
     
     
         2 . A slipform apparatus according to  claim 1 , wherein a safety barrier is provided between each work level and the central space. 
     
     
         3 . A slipform apparatus according to  claim 1 , wherein each of the plurality of work levels around a perimeter of the platform comprises a regular shape. 
     
     
         4 . A slipform apparatus according to  claim 1 , wherein the lift device is provided above the platform and said at least one cable is connected to the platform. 
     
     
         5 . A slipform apparatus according to  claim 4 , wherein the platform further comprises a portion thereof for constructing a secondary slipform structure of the primary slipform structure, the portion extending through the plurality of work levels. 
     
     
         6 . A slipform apparatus according to  claim 5 , wherein the portion of the platform comprises a part-ring shape which is suitable for forming the secondary slipform structure as a vertical tubular structure within the primary slipform structure. 
     
     
         7 . A slipform apparatus according to  claim 5 , wherein the portion of the platform comprises at least a part thereof which is planar which is suitable for forming a flat internal vertical face of the primary slipform structure. 
     
     
         8 . A slipform apparatus according to  claim 5 , wherein the portion is suitable for forming the secondary slipform structure comprising a duct or void in a side wall of the primary slipform structure. 
     
     
         9 . A slipform apparatus according to  claim 5 , wherein the safety barrier is provided between the central space and the portion of the platform for constructing the secondary slipform structure. 
     
     
         10 . A slipform apparatus according to  claim 9 , wherein the lift device comprises one or more winches or strand jacks, each winch or strand jack having a respective cable. 
     
     
         11 . A slipform apparatus according to  claim 10 , wherein the or each winch or strand jack is interconnected by a Grillage framework. 
     
     
         12 . A slipform apparatus according to  claim 10 , wherein the platform has shuttering depending therefrom for containing poured concrete of the primary slipform structure until it has set, said shuttering being on one or both sides of the primary slipform structure. 
     
     
         13 . A slipform apparatus according to  claim 12 , wherein the platform includes inner shuttering and outer shuttering, wherein the inner shuttering depends from a first work level, and the outer shuttering depends from a second work level via cabling. 
     
     
         14 . A method of operating a slipform apparatus to construct a primary slipform structure in a shaft from one side thereof, the slipform apparatus comprising a platform having a plurality of work levels around a perimeter thereof and surrounding a central space through the plurality of work levels, and a lift device to raise or lower the platform, the method including:
 suspending the platform from above using the lift device;   performing a rebar installation operation comprising raising the platform using the lift device and installing at least one rebar cage;   using the lift device to lower the platform to a base of the at least one rebar cage; and   performing a concrete slipform operation of the at least one rebar cage comprising raising the platform using the lift device.   
     
     
         15 . A method according to  claim 14 , wherein said rebar installation operation further includes using one of the plurality of work levels to install vertical reinforcing bars and another of the plurality of work levels to install horizontal reinforcing bars. 
     
     
         16 . A method according to  claim 14 , wherein said concrete slipform operation further includes using one of the plurality of work levels for pouring of the concrete and another of the plurality of work levels to finish the set concrete. 
     
     
         17 . A method according to  claim 14 , and further including preparing a diaphragm wall of the shaft using the platform prior to performing said rebar installation operation. 
     
     
         18 . A method according to  claim 17 , wherein said preparing the diaphragm wall comprises installing a waterproof barrier thereto. 
     
     
         19 . A method according to  claim 14 , and further including assembling the platform at a base of the shaft prior to operation thereof. 
     
     
         20 . A method according to  claim 14 , wherein the lifting device comprises one or more winches or strand jacks having a respective cable, the method further including:
 connecting each respective cable between the platform and a top of the shaft, and   operating the one or more winches or strand jacks to raise or lower the platform.   
     
     
         21 . A method according to  claim 20 , wherein the or each winch or strand jack is interconnected by a Grillage framework. 
     
     
         22 . A method according to  claim 14 , wherein said rebar installation operation further includes installing more than one rebar cage wherein a subsequent rebar cage is installed by lowering the platform and then raising the platform using the lift device and installing the subsequent rebar cage. 
     
     
         23 . A method according to  claim 14 , wherein the platform further comprises a portion thereof extending through the plurality of work levels, the method further including constructing a secondary slipform structure of the primary slipform structure using the portion. 
     
     
         24 . A method according to  claim 23 , wherein the portion of the platform comprises a part-ring shape, the method including constructing the secondary slipform structure from rebar as a vertical tubular structure using the part-ring shape portion, said vertical tubular structure being within the primary slipform structure. 
     
     
         25 . A method according to  claim 24 , and further including constructing the vertical tubular structure during said rebar installation operation or during said concrete slipform operation. 
     
     
         26 . A method according to  claim 25 , and further including performing said concrete slipform operation of the vertical tubular structure. 
     
     
         27 . A method according to  claim 23 , wherein the portion of the platform comprises at least a part thereof which is planar, the method including constructing a flat internal vertical face of the primary slipform structure using the planar portion. 
     
     
         28 . A method according to  claim 23  any of  claims 23  to  27 , and further including constructing the secondary slipform structure comprising a duct or void in a side wall of the primary slipform structure. 
     
     
         29 . A method according to  claim 14 , wherein the platform has shuttering depending therefrom on one or both sides of the primary slipform structure, the method further including using said shuttering to contain the poured concrete on one or both sides of the primary slipform structure until it has set. 
     
     
         30 . A method according to  claim 29 , wherein the platform includes inner shuttering and outer shuttering, wherein the inner shuttering depends from a first work level, and the outer shuttering depends from a second work level via cabling.