AU2012101074A4 - A component tunnel ceiling structure and method of installing the same - Google Patents

Abstract

A component tunnel ceiling structure including anchor members projecting from opposite inner walls of the tunnel, suspension rods suspended from the anchor members, removable guide wires adapted to be fastened onto free ends of the suspension rods, the guide wires adapted to guide and pass the suspension rods through apertures provided in one or more ceiling sections, wherein the guide wires are removed and suspension plates are fixed to the ends of the suspension rods protruding from the apertures to position the ceiling sections against the tunnel wall. A method of using the same.

Description

Editorial Note 2012101074 There are 9 pages of Description INNOVATION PATENT APPLICATION A COMPONENT TUNNEL CEILING STRUCTURE AND METHOD OF INSTALLING THE SAME. FIELD OF THE INVENTION This invention relates to tunnel construction in particular but not exclusively to a tunnel ceiling for use as a smoke duct and a method of installing the ceiling. BACKGROUND OF THE INVENTION Tunnel construction is a highly specialised field of engineering endeavour. Tunnels conveying rail, traffic and transport in general for long distances have to provide safe and adequate levels of ventilation. This is critical where there is a possibility of a breakdown in traffic flow and especially if there is a fire in the tunnel. The construction of smoke ducts by suspending a ceiling from the roof of a tunnel to form a passage way for the extraction of smoke in the event of fire is known prior art. Current methods of erecting a ceiling in a tunnel involve the construction of one or more supporting ledges known in the industry as corbels along each side of the tunnel wall and placing a series of ceiling panels on top of the corbels. The ceiling panels spanning between and supported by the opposite corbels are typically made from reinforced concrete or other fire-rated and structurally sound material. Ceiling panels are also generally required to be separated from the corbels so that they can move independently in the event of thermal expansion caused by a fire or the expansion or contraction of the tunnel wall under normal conditions. Prior art corbels are generally made of reinforced concrete and are fixed to the tunnel wall by means of anchor members protruding from the tunnel walls. Corbels can also be fabricated from steel and bolted to the wall using the anchors. Steel corbels however require protection with fire retardant material to prevent failure when exposed to extreme heat in the event of a tunnel fire. Concrete corbels are typically constructed by fixing formwork to the tunnel wall, fixing reinforcing steel in place, placing concrete into the formwork and then, after the concrete has reached the requisite strength rating, removing the formwork. The problem with this method is that it is very labour intensive and time consuming. As an example, pursuant to engineering design criteria, ceiling panels cannot be installed onto the concrete corbels until they have been cured to a twenty eight (28) day design strength rating. This time delay is a major disadvantage to the construction project and costs as a whole. Another method of constructing a corbel is by manufacturing a precast concrete corbel and bolting it to the tunnel wall by using anchors protruding from the tunnel wall. The problem with this method is that precast corbels are manufactured well in advance of when they are required to be erected in order for them to have reached their required design strength. As such, they need to be manufactured with a predetermined tolerance of anchor fixing positions to ensure accurate placement on the anchors protruding from the tunnel wall. It is very difficult to ensure the accuracy of the fixing positions in precast corbels when taking into consideration variances that may occur on site when installing the anchors protruding from the tunnel wall. As a result, the voids through which the anchors are fixed need to be oversize and later grouted. These issues make the erection of precast corbels very time consuming and labour intensive. In most cases, to accommodate the abovementioned problems, the erection of the corbels is carried out as a separate process. The erection of the ceiling slabs is then a further process following the installation of the corbels. OBJECT OF THE INVENTION There is therefore a need for a novel and innovative component tunnel ceiling structure and a method of installing the same which also seeks to overcome or ameliorate the limitations and disadvantages of the prior art or to at least provide the public with an alternative and useful choice. STATEMENT OF INVENTION In one aspect the invention resides in a rapid installation component tunnel ceiling structure including in combination: anchor members projecting from opposite inner walls of the tunnel; suspension rods suspended from the anchor members; removable guide wires where necessary adapted to be fastened onto free ends of the suspension rods; wherein the guide wires further adapted to guide and pass the suspension rods through apertures provided in one or more ceiling sections, and wherein the guide wires are removed and suspension plates are fixed to the ends of the suspension rods protruding from the apertures to position the ceiling sections against the tunnel wall. Preferably, the suspension rods include one or more threaded extension rods. Preferably the suspension rods also referred to as hanging rods are suspended from the anchor members by means of a pivot block or shackle allowing for movement in at least two directions. Preferably, the suspension plates are fixed to the suspension rods or extension rods by a nut. Preferably, the suspension plates optionally incorporate an integrated threaded insert, wherein the plate is adapted to be screwed directly onto the suspension or extension rods. Preferably, each ceiling section comprises a platform member having walled ends specially adapted to form a boxed cavity when positioned against the tunnel wall, into which concrete can be poured to form a structurally confluent and integral corbel with the tunnel wall and wherein multiple ceiling sections can be erected without depending on concrete of previously poured corbel cavities reaching their requisite design strength. Preferably, the ongoing erection of ceiling sections is not reliant on the poured concrete reaching a predetermined design strength. Preferably, a reinforcing frame is positioned in the boxed cavity such that the corbel thus formed is a reinforced concrete structure. Preferably, the anchor members are threaded studs projecting horizontally from the tunnel walls by which the corbel is also bolted to the tunnel wall.

Preferably, there are secondary anchor members which co-operate with the reinforcing frame to further secure the corbel to the tunnel wall. Preferably, when the reinforced concrete corbel has cured to a predetermined strength, the suspension plates, any nuts and threaded extensions can be removed. Preferably, there is gap adjustment means between the corbels and the platform member, wherein spacer members or shims can be inserted to fill any gaps between a corbel and the platform member to accommodate any contraction of the platform members. Preferably, the gap adjustment means comprises a horizontal threaded bolt and blind nut in the platform member and corbel which is tightened to compress any spacers located there between such that a unitary ceiling section is formed. In another aspect, the present invention resides in a method for installing a ceiling in a tunnel using the ceiling structure hereinbefore described which includes the steps of: (a) raising one or more ceiling sections into a position adjacent to the tunnel wall using a raising means, the ceiling section having one or more apertures; (b) inserting guide wires into the apertures of the ceiling sections; (c) raising the ceiling section further, wherein the suspension or extension rods pass through the ceiling section and the walled ends come into contact with the tunnel wall to thereby form a boxed cavity; (d) removing the guide wires and replacing the same with one or more suspension plates; (e) removing any temporary brackets and connecting the anchors to the corbel such that the corbel is pulled against the tunnel wall; (f) tightening the suspension plates onto the ends of the suspension or extension rods to a predetermined tension; (g) releasing the raising means; (h) pouring concrete into the boxed cavity having one or more anchor members and over a reinforcing frame if required to form a corbel structurally integral with the tunnel wall; (i) repeating steps (a) to (g) for the next abutting ceiling section; (j) on the concrete curing to a predetermined strength, removing the suspension plates, nuts and extension rods; and (k) filling any remaining voids.

BRIEF DESCRIPTION OF THE DRAWINGS In order for the invention to be better understood reference will now be made to the accompanying drawings, wherein; Figure 1 shows a preferred suspension rod assembly according to the invention. Figure 2 shows the suspension rod of Figure 1 in use. Figure 3 shows corbel ends of Figure 2 in situ. Figure 4 shows detail of the ceiling section according to the invention. Figure 5 shows a preferred pivoting bracket means according to the invention.

DETAILED DESCRIPTION OF THE DRAWINGS Referring now to Figure 1 there is shown a preferred suspension or hanging rod assembly according to the invention. The hanging rod 10 is suspended from the threaded anchor member 12 anchored in the tunnel wall 14 by means of a joiner nut or coupler 12a and a pivot block 16 or shackle which allows the rod to move in at least two directions. This facilitates location of rods in the apertures of the ceiling section (not shown). The suspension rod includes a threaded extension rod 18 joined to it preferably by an internal threaded sleeve 20. There is also shown suspension plate 22 and nut, 24. The extension rod 18 may also have a square or hexagonal end 18a to facilitate its later removal by use of a tool. Figure 2 shows detail of the suspension or hanging rod in use according to the invention. The suspension rods 26, 28 are guided and inserted into the apertures 30, 32 in the corbel end 34 of the ceiling section by means of guide wires 36, 38 which preferably have guide rods 40, 42 for inserting into the apertures. The guide rods are temporarily connected to the ends of the suspension rods by threaded caps 44, 46. On raising the corbel ends to the walls of the tunnel, the guide wires are unscrewed and replaced with suspension plates and nuts (both not shown) which are tightened to a predetermined tension. The corbel ends form a hollow boxed cavity with the tunnel wall 48 into which concrete is poured over a reinforcing frame 50. On the concrete reaching its design strength the suspension plates and the extension rods may be removed and the voids are grouted over. Figure 3 shows a corbel end 35 located in place against the tunnel wall 48. Tensioning the nuts 52, 54 and 53, on the extension rods 56, 58 and anchor member 60, pulls the corbel end 35 tightly against the tunnel wall 48. Concrete is then poured over the reinforcing frame 64 in the boxed cavity 66 formed which also seals in place the anchors 60, 62 and suspension rods 57, 59. Also shown is compressible spacer 68 or shim, between the platform 70 and the reinforced corbel thus formed allowing for expansion or contraction of the platform 70 independently from the corbel end 35. Referring now to Fig.3a anchor member 60 protrudes through formed oversize void in the corbel end 35.A flanged recess former 55 provides enough depth so that the anchor member 60 does not protrude past any predetermined distance from the outer face of the corbel end 35.The flanged end 55a of the flanged recess former 55 can be positioned to the outer face of the corbel end 35 but with sufficient concrete cover as required extending the effective anchorage length of anchor member 60. The flanged recess former 55 also has a flanged base 55b that allows a slotted washer 55c to rest against. The anchor member 60 can be in two parts and joined by a joiner nut 60a. The first part of anchor 60 will be fixed into the tunnel wall 48, whereas the second part of the anchor member 60 can be secured to the first part by means of the joiner nut 60a and to the corbel end 35 by tensioning the nut 53 against the slotted washer 55c which sits against the flanged base 55b of the flanged insert 55. The second part of the anchor member 60 may also have a square or hexangonal end 60b to facilitate its tightening into the joiner nut 60a. Referring now to Figure 4 there is shown detail of a ceiling section 72 comprising a ceiling platform member 74 which is supported between opposite walled corbel ends 76, 78 which form a boxed cavity when positioned against the tunnel wall (not shown). Concrete poured over the reinforcing frame 80 in the boxed cavity results in a reinforced corbel integrated with the tunnel wall. Figure 5 shows a preferred pivoting bracket means to secure the platform member 82 to a corbel 84. In this arrangement, the platform member rests on top of the upper surface of the corbel for the purpose of the erection phase. The bracket 86 is fixed to the platform member and is tied down by a turn buckle or threaded hold fast pivotally attached to an eye embedded in the corbel. Another temporary bracket 86a is used to hold corbel 84 in its most contracted position relative to the platform member 82 until it has been raised into position. Any lateral displacement of the platform member (shown by Figs. Sa - 5c) required to accommodate construction tolerances of the tunnel is enabled after the removal of the temporary bracket 86a while still connecting the platform to the corbel. Detail of the pivoting bracket means per se is shown in Fig.5e. In this drawing, the bracket portion 86 and the eye 92 is embedded in the platform and the corbel (both not shown) by feet members 94 ,96. The threaded hold fast is tensioned down by nut 90 having an arcuate base 90a to accommodate the angular displacement of the hold fast 88 as the platform 82 expands Fig.5a or contracts Fig.5c from its resting position Fig.5b. on the corbel 84.This bracket assembly as shown in Fig. 5e, is later removed prior to the placement of concrete. It will be obvious that a plurality or series of abutting ceiling sections along the length of a tunnel will form an upper ceiling with the tunnel roof which can be utilised as a smoke duct or a storage space or passage way for utilities such a electrical, communication and gas conduits and pipes. This proposal has been developed by the present inventors to provide an innovative solution that will save overall project time and costs as well as providing a much safer and less labour intense method of constructing the smoke duct slab & corbel. This proposal includes the following fundamental advantages, among others: * The smoke duct slab & its associated corbels can be erected together in one operation - erection time will be reduced by at least 50% when compared to the combined operations of erecting corbels and then smoke duct slabs individually (without even considering time lost waiting for insitu concrete and/or grout to reach design strengths); " The corbel fixing method provides for vertical, horizontal and lateral movement, accommodates tunnel construction tolerances, and is secured only to the anchors already designed for the structure -there is no additional propping required nor any additional fixings over and above those already required for the structure in its final design state out of tolerance anchor positioning can also be easily accommodated; * The temporary connections fixing the corbel to the smoke duct slab during the erection phase are easily removed (for re-use) after the corbel is secured allowing the smoke duct slab to move independently from the corbel; * The possible elongation of the tunnel to tolerances advised can be provided for within the design of this proposal - the assembled units are raised into position in their most contracted position before the release of the temporary brackets allows the corbel to be secured against the tunnel wall; * The use of insitu concrete to complete the final design state of the platform member and corbel has been removed from the critical path the use of normal grade concrete instead of high early strength concrete is achieved because the erection and installation of the units is no longer dependant on the placement of concrete nor the requirement for it to reach its design strength earlier than 28 days; * With fewer operations required in the platform and corbel erection, there are less activities, less tunnel construction traffic and congestion, and fewer men on site, all resulting in a reduced safety risk -installation processes are conducted from beneath the unit and can be easily achieved from elevated platforms - there is no need to have people on top of the units, potentially out of sight, during the erection process; e The placement of insitu concrete to the erected units can be carried out from a much safer working platform when compared to the option of forming and casting the corbels insitu. It will of course be realised that while the foregoing has been given by way of illustrative example of this invention, all such and other modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of this invention as is herein set forth. In addition to the above, it should be appreciated that throughout the specification the terms "comprising" and "containing" shall be understood to have a broad meaning similar to the term "including" and will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. This definition also applies to variations on the terms "comprising" and "containing" such as "comprise", "comprises", "contain" and "contains".

Claims (5)

1. A component tunnel ceiling structure including in combination: anchor members projecting from opposite inner walls of the tunnel; suspension rods suspended from the anchor members; removable guide wires where necessary adapted to be fastened onto free ends of the suspension rods; the guide wires further adapted to guide and pass the suspension rods through apertures provided in one or more ceiling sections, wherein the guide wires are removed and suspension plates are fixed to the ends of the suspension rods protruding from the apertures to position the ceiling sections against the tunnel wall.

2. The tunnel ceiling structure as claimed in claim 1 wherein each ceiling section comprises a platform member having walled ends specially adapted to form a boxed cavity when positioned against the tunnel wall, into which concrete can be poured to form a structurally confluent and integral corbel with the tunnel wall and wherein multiple ceiling sections can be erected without depending on concrete of previously poured corbel cavities reaching their requisite design strength.

3. The tunnel ceiling structure as claimed in claim 2 wherein a reinforcing frame if required can be positioned in the boxed cavity such that the corbel thus formed is a reinforced concrete structure.

4. The tunnel ceiling structure as claimed in any of the above claims wherein the suspension rods are suspended from the anchor members by means of a pivot block or shackle allowing for movement in at least two directions.

5. A method for installing a ceiling in a tunnel using the component ceiling structure hereinbefore described, which includes the steps of: (a) raising one or more ceiling sections into a position adjacent to the tunnel wall using a raising means, the ceiling section having one or more apertures; (b) inserting guide wires into the apertures of the ceiling sections; (c) raising the ceiling section further, wherein the suspension or extension rods pass through the ceiling section and the walled ends come into contact with the tunnel wall to thereby form a boxed cavity; (d) removing the guide wires and replacing the same with one or more suspension plates; (e) removing any temporary brackets and connecting the anchors to the corbel such that the corbel is pulled against the tunnel wall; (f) tightening the suspension plates onto the ends of the suspension or extension rods to a predetermined tension; (g) releasing the raising means; (h) pouring concrete into the boxed cavity having one or more anchor members and over a reinforcing frame if required to form a corbel structurally integral with the tunnel wall; (i) repeating steps (a) to (g) for the next abutting ceiling section; (j) on the concrete curing to a predetermined strength, removing the suspension plates, nuts and extension rods; and (k) filling any remaining voids.