GB2473026A

GB2473026A - Lift shaft assembly comprising pre-fabricated concrete sections

Info

Publication number: GB2473026A
Application number: GB0914978A
Authority: GB
Inventors: Steve Perkin
Original assignee: WAYCON PRECAST Ltd
Current assignee: WAYCON PRECAST Ltd
Priority date: 2009-08-26
Filing date: 2009-08-26
Publication date: 2011-03-02
Also published as: GB0914978D0

Abstract

The lift shaft assembly is formed from concrete sections which are assembled to span a plurality of storeys, each storey comprising four side walls 3-5 extending between top 8 and bottom 9 faces, wherein each storey includes ducts 16 extending between the top and bottom faces. Each duct may extend between top 17 and bottom 18 plates recessed into the faces. The ducts of the sections may be aligned in order to receive reinforcing bars 25 that are anchored beneath the bottom storey and tensioned against the top plate of each story. The reinforcing bars may be tensioned against tensioning plates 27, which are located between each top plate and the bottom plate of the storey immediately above. Each storey may include a door section 1 having a door aperture 10 and a spacer section 2 located above the door section.

Description

PREFABRICATED CONCRETE SECTIONS AND

LIFT SHAFTS CONSTRUCTED THEREFROM

TECHNICAL FIELD OF THE INVENTION

This invention relates to lift shafts which are constructed from prefabricated concrete sections. (0

BACKGROUND Co

GB 2 363 110 A discloses a lift shaft which is prefabricated in reinforced concrete sections which are stacked one upon another. Each section has four integrally-formed sides. The sections include alternate door sections and shorter spacer sections, the door sections having a rectangular door aperture formed in one side. The opposed top and bottom faces of the stacked sections are provided with projecting bars and sockets.

The sections are formed by moulding within inner and outer shuttering secured to a vibrating table.

It is also known from GB 2 437 142 A to incorporate a reinforcing post into each corner during casting of the sections.

The post may include a vertical element which is encased in concrete with top and bottom plates which define the top and bottom corner faces of the section. The top plate has a screw threaded socket for receiving a lifting loop or a locating pin, and the bottom plate has a socket for receiving the pin of another such section. One of the locating pins may be significantly higher than the others to assist location during assembly of the lift shaft.

Such assembly methods allow tall lift shafts to be constructed very quickly, but there is currently a limit to the number of storeys which can be built.

The present invention seeks to provide a new and inventive way of constructing lift shafts from prefabricated concrete sections CO which allows a greater number of storeys to erected. (\J

SUMMARY OF THE INVENTION

The present invention proposes a lift shaft assembly formed of prefabricated concrete sections which are assembled to span a plurality of storeys, each storey comprising four side walls extending between top and bottom faces, and in which each storey incorporates ducts extending between said top and bottom faces for insertion of tensioning bars during erection of the lift shaft.

The number of case ducts and tensioning bars required is determined by detailed srucural design, to suit the prescribed loadings from the surrounding srucWre of the building.

The ducts are preferably case into the walls or the corners during casting of the secUons. Each duct preferably extends between op and bottom plates a said top and bottom faces. Preferably a lease one of the op and bottom plates is recessed below the adjacent op or bottom face of the side walls.

During insallaion, the ducts are mutually aligned so that they can receive respective reinforcing bars which may be anchored into footings below the sections. The reinforcing bars may be tensioned against a tensioning pIae Iocaed between the op plate and bottom plate of wo stacked sections. Co (\J

BRIEF DESCRIPTION OF THE DRAWINGS

The following description and the accompanying drawings referred o therein are included by way of non-limiting example in order o illusrae how the invention may be pu into practice.

In the drawings: Figure 1 is a general view of wo bottom sections which form one sorey of a lift shaft assembly in accordance with the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

Fig. 1, shows a door section 1 and a spacer section 2 which together form a single sorey of a twin lift shaft ha spans several soreys of a building. The door section is of standard height, e.g. 2.2 metres, while the spacer section is of a smaller height which is selected from a range of standard heights or specially fabricated o suit the floor spacing of the building.

Where the size or weight of the sections dicae, additional joints may need o be provided so ha each storey is formed from more than wo sections.

Both sections 1 and 2 are of recanguIar shape with front and rear walls 3 and 4, joined by a pair of end walls 5 and 6 which CO together define an internal vertical shaft 7. The four walls 3 o 5 extend between op and bottom faces 8 and 9 of the section. In the case of the spacer section 2 the four walls are continuous with no gaps, but in the case of the door section 1 the front wall has a gap forming a door aperture 10 providing access o the shaft 7. The door aperture thus completely divides the front The junction between the walls 3-6 form four corners 12-15 extending between the op and bottom faces 8 and 9. Each corner incorporates a duct 16 extending between the op and bottom faces, e.g. a steel tube, which is case into the concrete section. The number of ducts and tensioning bars is determined by detailed structural design. The tube 16 is secured to rectangular top and bottom plates 17 and 18, the edges of which extend a short distance along the outer faces of the wall sections, thereby proecing them from damage during handling of the sections. One or both of the plates 17 and 18 may be recessed a shore distance below the op face 8 of the adjacent wall sections, bu in this example only the op plate 17 is recessed. The op plate 17 incorporates an internally screw-threaded socket 19 which is secured o a lifting anchor 20 embedded within the case section while the bottom plate 18 incorporates a plain socket 21. During insallaion of a section the threaded sockets 19 each receive a lifting loop 22 which is used W lift the section into position, as shown for the spacer section 2. When the section is in place the lifting loops are unscrewed and replaced with locating dowel pins 23 which are CO screwed into the sockets 19, as shown for the door section 1. (\J

When the next section is lowered into position the upwardly projecting dowel pins 23 are received in the bottom sockets 21 of the next section when it is lowered into position, thereby providing positive location of the sections. One of the four dowel pins 23 may be significantly longer than the other three o assist location during lowering of a section.

The lift shaft is formed of door and spacer sections which are stacked one upon another o span the required number of soreys in the building. Prior to insallaion of the bottom door section 1 lengths of threaded reinforcing bar 25 are anchored into concrete footings a 26 in alignment with the ducts 16. The bottom section is then lowered over the bars 25. A tensioning plate 27 is then placed over the projecting top portion of each bar 25 abutting the top plate 17, and the bar is tensioned against the plate 27 by means of nuts 28. Another length of threaded bar is then secured to the top of the first length by means of splicing tubes or couplers 30, and the next section 2 can then be lowered over the tensioning bars. The couplers 30 enter the ducts 16 whereas the tensioning plates 27 are received in the recesses formed between the opposing top and bottom plates 17 and 18 of adjacent stacked sections 1 and 2.

The bars 25 are similarly tensioned during the installation of each section using further tensioning plates 27 and nuts 28.

By clamping the sections together by means of the tensioned bars 25 it is possible to construct shafts which are taller and CO stronger than has hitherto been possible. (\J

Whilst the above description places emphasis on the areas which are believed to be new and addresses specific problems which have been identified, it is intended that the features disclosed herein may be used in any combination which is capable of providing a new and useful advance in the art.

Claims

CLAIMS1. A lift shaft assembly formed of prefabricated concrete sections which are assembled W span a plurality of soreys, each sorey comprising four side walls extending between op and bottom faces, and in which each sorey incorporates ducts extending between said op and bottom faces for insertion of tensioning bars during erection of the lift shaft.
2. A lift shaft assembly according o Claim 1 in which each duct extends between op and bottom plates a said op and bottom faces. (0

Q
3. A lift shaft assembly according o Claim 2 in which a CO lease one of the op and bottom plates is recessed below the adjacent op or bottom face of the side walls.
4. A lift shaft assembly according to any preceding claim in which the ducts are muwally aligned and receive respective reinforcing bars.
5. A lift shaft assembly according o Claim 4 in which the reinforcing bars are anchored into footings beneath the bottom sorey.
6. A lift shaft assembly according o Claims 2 and 5 in which the reinforcing bars are each tensioned against the op plate of each sorey.
7. A lift shaft assembly according o Claim 6 in which the reinforcing bars are each tensioned against a tensioning plate located between each op plate and the bottom plate of the sorey immediately above.
8. A lift shaft assembly according o any preceding claim in which each sorey includes a door section including a door aperture and a spacer section with no door apertures located above the door section.
9. A lift shaft assembly which is subsanially as described with reference o the drawing. Co (\J