GB1590214A

GB1590214A - Situ cast beams

Info

Publication number: GB1590214A
Application number: GB15414/78A
Authority: GB
Original assignee: Pynford Ltd
Current assignee: Pynford Ltd
Priority date: 1978-04-19
Filing date: 1978-04-19
Publication date: 1981-05-28
Also published as: BE871387A; FR2441032A1; MX149506A; IT1108486B; DE2845443A1; NL7810410A; IT7869390A0; FR2441032B3

Description

(54) IMPROVEMENTS RELATING TO SITU CAST BEAMS (71) We, PYNFORD LIMITED, a British company, of 74 Lancaster Road, Stroud Green, London, N.4., do hereby declare the invention, for which we pray that a patent may be granted to us and the method by which it is to be performed, to be particularly described in and by the following statement:- The invention is concerned with stools for use in the construction of in situ cast beams in the walls of buildings.

Such beams are used in the underpinning and repair of buildings, for example when underpinning a cracked wall, the foundation of which have been subject to subsidence. The beam is inserted in the wall of the building parallel to the plane of the wall and the load will then be redistributed by the beam onto the foundations, which may be renewed at the same time. The beams are also used as lintel beams which are inserted into the wall prior to cutting away the wall beneath the central portion of the beam.

A conventional in situ cast beam is constructed by cutting away the wall and inserting at horizontally spaced positions, props, which in this context are generally, and are hereinafter, referred to as stools. The stools are built in and pinned up to support the wall above. With the intervening wall between the stools cut away, reinforcing rods are inserted, formwork is erected, and an in situ beam is cast incorporating the reinforcement and the stools. Mortar is then packed into the space between the top of the cast beam and the raw wall above between the stools to pin up the beam along its full length.

Since a comparatively large number of stools have to be handled and sacrificed in the construction of the beam, it is desirable that they should be of the cheapest and simplest possible construction and as small and as light in weight as possible although adequately sturdy.

Conventionally the pinning up to the stools is a laborious business and time has to be allowed for the mortar, which is used for the pinning up, to set before the wall between the stools can be cut away and the beam cast. It is known to use, in association with the stools, a screw jack in order to tighten and pin up the stools quickly. This enables the stools to be inserted successively along the wall with each stool being inserted into an aperture cut simultaneously with the removal of the intervening wall between that stool and the immediately preceding stool. Of course the stools can be used in more conventional fashion and inserted in horizontally spaced apertures in the wall before the intervening wall is cut away.

The stools disclosed in our specification No. 827,838 incorporate jacking screws between upper and lower plates of the stool and there is described in our Specification No.

1,497,412 a thin plate screw jack for insertion between the top of the stool and the wall above. However, these earlier proposed screw jacks involve the use of screws which are short by comparison with the height of the stool and, although they are sufficient to enable the stool to be pinned up, the stroke is insufficient to lift the wall above, if cracked, sufficiently to close the cracks to any significant extent. The stitching up and filling of the cracks then becomes a further laborious operation. Furthermore, the earlier integral or plate screw jacks are expensively constructed items and add to the cost of the operation, either in the time required for their recovery during the construction of the beam or in their cost if they are sacrificed by being left within the beam.

In our Cognate British Patent Application No 5474/77, 17315/77,26812/77 and 35705/77, we disclose a stool comprising two body portions each comprising a cylindrical shell filled with a concrete or other load bearing grout. A screw threaded socket is cast into one of the body portions and a screw threaded spindle screws through the screw-threaded socket with its free end engaging rotatably in a socket cast into the other body portion. The spindle carries a fixed nut by which the spindle can be rotated to force the body portions apart, in use to tighten the stool in the wall.

As disclosed in these earlier cognate Applications, the socket in which the free end of the spindle is rotatable is of significant axial length and surrounds the end of the spindle with only a slight clearance. This makes it difficult to use the stool when there is any significant axial misalignment between the two body portions, owing perhaps to the undersurface of the wall above or the upper surface of the wall below being out of the horizontal, and jaming of the end of the spindle in the socket can occur and prevent free rotation of the spindle.

In accordance with the present invention, a stool for use in the construction of an in situ cast beam comprises upper and lower body portions the lower of which is arranged to be supported on the wall below and the upper of which is arranged to be used in load-bearing engagement with the wall above, and one of which includes a screw-threaded socket having a vertical axis: and a screw-threaded spindle which screws through the screwthreaded socket and which includes means for enabling the rotation of the spindle relative to the screw-threaded socket, the other of the body portions or the spindle having an axially facing socket, the socket being arranged to receive, respectively, the end of the spindle or the end of a stub shaft extending from the other body portion, with a clearance between the spindle or stub shaft respectively and the surrounding wall of the socket whereby the other body portion may rock on the end of the spindle to allow the stool to adapt to the shape of the wall above and below.

Preferably, the socket is of short axial length, but the socket may be open ended and the clearance between the spindle or stub shaft and socket alone allowing rocking to take place.

The end of the spindle or the end of the stub shaft may have a chamfered edge or be rounded to facilitate relative movement between the body portion and the spindle.

In the preferred arrangement the engagement between the end of the spindle and the socket should be such that the upper body portion can rock through 10 or even 15 in any direction relatively to the spindle. This angular movement will be determined by the depth of the socket and the clearance between the spindle or stub shaft and socket wall.

The socket preferably has a depth less than one-third of its internal diameter.

The lower body portion may comprises a cylindrical shell filled with a cement, concrete, or other load bearing grout into which the screw-threaded socket is cast, similarly to the manner described in the previously referred to earlier cognate Application. In that case an inner sleeve may be cast into the grout in alignment with the screw-threaded socket to provide an internal axial passageway in which the lower end of the spindle is accommodated when retracted.

Preferably, however, the lower body portion comprises a precast concrete member, in which the screw-threaded socket is embedded, or on which is supported a plate provided with the screw-threaded socket. The plate may be steel plate which may be resin bonded to the precast concrete member or supported by an interposing thin, paper or felt gasket, and the screw -threaded socket may then be a nut welded to the top of the steel plate and in alignment with a hole through the plate.

Alternatively, the plate may be formed by a steel casting in which is integrally incorporated the screw-threaded socket, supported upwardly from the plate, if required, by upstanding webs or shoulders. The precast concrete member will also have a passage in alignment with the socket to receive the lower end of the spindle when retracted.

The precast concrete member may be rectangular in plan and saddle shaped to accommodate on each side reinforcement for the beam. The saddle shaped member will then have a raised central portion with a flat top on which the plate is supported. The upper body portion of the stool may incorporate a steel plate which abuts or is resin bonded to the under-side of a precast reinforced conrete member which may be the same shape as that of the lower body portion, so that both can be formed in the same shape mould.

If the arrangement is such that the socket receives the upper end of the spindle, then the socket may be provided by an annular collar which depends from and is welded to the underside of the steel plate. Alternatively the plate and collar may be a steel casting.

If the arrangement is such that a stub shaft extending from the upper body portion is supported in the socket then the socket may be formed by a nut welded or otherwise fixed at the top of the spindle, the nut being screwed only partially onto the spindle so that the base of the socket is formed by the top end of the spindle. In this case it may be possible to form the lower and upper body portions with substantially indentical castings providing the plates, so that, again, the number of moulds to be used can be significantly reduced. The stub shaft, which may, together with the spindle, be tubular rather than solid, can then be welded, screwed, or otherwise attached to the upper body portion steel plate or casting.

The nut on the screw-threaded spindle is used to enable rotation of the spindle by cooperation with a complementary spanner.

Preferably, the spindle has a left-handed thread so that, when viewed from above, clockwise rotation of the spindle raises the spindle. This is significant in practice because it is much easier, for a right-handed person to operate in a clockwise fashion.

If the screw-threaded socket is a nut welded to a plate a spanner may be fitted to the nut to enable twisting of the lower body portion to be resisted when the spindle is turned. If a cast ing is incorporated in the lower body portion or other means of fabrication is employed, an alternative means of resisting rotation would be to provide vertical faces parallel to the axis of the spindle that could be engaged by a spanner or by providing a hole into which a tommy bar could be fitted.

It will be noted that the torque required to resist rotation reduces as friction builds up between the lower body member and the supporting wall. To this end the contact surfaces between both the lower and upper body members and the wall or foundation, and between the lower and upper sockets where a thin paper or felt gasket is interposed between them and the lower and upper body members, may be slightly dished or relieved in the centre so that the bearing surface is under greater pressure at a distance from the axis of the spindle, thus maximising the restraining torque when the spindle is rotated relatively to the lower and upper body members.

Although previous beams are usually six courses of bricks deep it is envisaged that these new stools will enable four-course beams to be constructed and it is therefore important for the spindle to be long enough to provide the required lift and yet short enough to enable the lower body member to be as short as allowable for the expected loads. In order that the operator may check on the extent to which the spindle has been screwed out of the screw-threaded socket, a small hole may be formed in the bottom of the steel casting or near the top of the concrete member, extending transverse to the axis of the spindle to intersect the bore through which the spindle extends.By poking a wire or, if conditions allow, by sighting along the hole the operator can tell when the lower end of the spindle is approaching the lower end of the screwthreaded socket, thus allowing him to check that the spindle has not been rotated too far out of the screw-threaded socket.

Either or both of the concrete members may be formed with an enlarged counter-sink into which may locate a collar on the underside and top ride respectively of the lower and/ or upper body portion steel plates or castings to ensure centralisation of these on the conrete members, and to resist the rotation of the numbers when the spindle is rotated.

An example of a stool according to the invention, together with various possible modifications of the individual parts of the stool, will now be described with reference to the accompanying drawings in which: Figure 1 is a section through the wall showing the stool in side elevation; Figure 2 is a section, looking upwards, on the line 11-Il in Figure 1; Figure 3 is a front elevation; Figure 4 is a section on the line IV-IV in Figure 3; Figures 5 are cross-sections and other views showing variations of the upper concrete member; Figures 6 shows, in section, variations of the upperplate or castings; Figures 7 show three different types of spindle which may be used;; Figures 8 show, in section, variations for the lower plate or casting and Figures 9 show, again in section, variations of the lower concrete member.

Figures 1 to 4 show a basic example of the stool according to the invention and the remaining Figures show how variations can be incorporated within the scope of the invention. The stool includes upper and lower concrete members 1 and 2 each of which is rectangular in plan view.

The upper concrete member 1 is also rectangular in cross-section (as shown), but a number of variations are possible, for example as shown in Figures 5a through h.

The lower concrete member 2 is saddleshaped in cross-section so as to enable easy incorporation of longitudinal reinforcing rods 3, shown chain-dashed in Figures 1 and 3.

The lower concrete member 2 also tapers on its side faces as can be seen from Figures 3 and 4 and is slightly waisted, as seen from Figure 4.

Below the upper concrete member is a mild steel plate 4 to which is welded a very short length of the 5 which provides a socket of short axial length. The mild steel plate 4 can be resin bonded to the concrete member 1 if required and there may or may not be, as required, a thin felt or paper gasket interposed between the two in order to overcome the effect of any loading concentrations resulting from irregularities in the surface of the concrete member 1. The lower concrete member 2 likewise has a mild steel plate 6 abutting its surface and to this plate is welded a hexagonal, or other sectioned, nut 7. The nut 7 provides, a screw-threaded socket for receiving a spindle 8. In order to allow for extension of the spindle below the socket both the plate 6 and the concrete member 2 include a central bore.

The spindle 8 may, as shown, be tubular or may be solid. The upper end portion 9 of the spindle is preferably not screw-threaded, unlike the lower portion 10 which has to engage in the nut 7. Preferably, the screw threads are left-handed to ease operation for a right-handed operator. The upper portion 9 is a loose fit within the socket 5 so that the upper concrete member 1 together with the associated plate 4 can be tilted relative to the spindle 8 so that irregularities in the opening into which the stool is fitted can be accommodated without the spindle jamming in the socket 5 and causing undue bending forces on the spindle.A nut 11 which may or may not be screw-threaded, is welded to the spindle adjacent its top end and, by use of an appropriate spanner on the nut 11 the spindle can be turned in a, preferably, clockwise direction as seen from above, to raise the spindle out of the lower concrete member 2.

In order to prevent undue twisting forces being transmitted to the lower concrete member 2 via the nut 7 and the plate 6 a second spanner can be positioned on the nut 7 to counteract the turning force on the spindle. The lower plate 6 is preferably resin bonded to the lower concrete member 2 again with or without an intermediate gasket.

In Figures 1 to 4 the stool is shown tightend in the horizontal slot cut in a 9" solid wall with the lower concrete member 2, resting on the wall below and with the spindle tightened up to take the weight of the wall above via the upper concrete member 1. It will be appreciated that there will be a number of the stools tightened into the wall in this way at for example one metre centres along the wall.

When the tightening has been completed, reinforcement will be inserted and appropriately supported, typical reinforcement being shown in Figure 1 as longitudinal rods 3 conventionally wired to stirrups (not shown).

Formwork is then erected at the exposed surface of the wall in front of the stools and at the rear surface of the wall if this is necessary, (for if the beam is constructed below ground level no formwork is generally required at the rear surface of the wall as the beam can be concreted against the existing ground or hardcore), and a concrete beam (shown in chain dashed lines in Figures 1 and 3) is cast, encapsulating the reinforcement and stools. The top of the beam is about 50 mm. short of the wall above and, when the beam has set, this gap is pinned up with earth damp mortar. When this mortar has set the underpinning is complete.

The various examples of the upper concrete member shown in Figures 5 all have a rectangular plan. The example shown in Figure 5a is substantially the same as that shown in Figures 1 to 4 and has a rectangular cross-section. The example shown in Figure Sb has a dished upper surface 12 in order that mortar which is used to bed the stool to the wall above does not squeeze out of the gap between the concrete member and the wall when the jack is tightened as readily as it does when a planar surface is provided on the top of the concrete member. The same example also includes steel reinforcement elements 13.

The example shown in Figure Sc is substantially similar to the bottom conrete member shown in Figures 1 to 4 in that it has a saddleshaped cross-section so that reinforcement for the beam can be provided at the positions indicated. The example shown in Figure Sd includes a dished top surface, is saddle-shaped in cross-section and also includes a countersunk recess 14 in its lower surface which can be used to co-operate with an extension from the plate or casting to provide for positive location of the plate or casting on the concrete member.

Preferably, the recess includes at least one flat side to resist turning of the plate relative to the concrete member.

Figures 5e, f, g and h show two further variations of the upper concrete member. In Figures 5e,f and g an upper member is shown with two substantially V-shaped tapering notches 15 positioned axially on the concrete member so as to lie between the two skins of brickwork when a beam is being built-in in a cavity wall. The widest part of each of the notches corresponds approximately to the width of the cavity and the taper of the notches provides for drainage of any moisture internally of the cavity. This can be important when the beam is being constructed immediately below the damp proof course in the wall. Figure 5h shows a second possibility also to provide drainage, in this case however the drainage being provided with a longitudinal channel the bottom of which tapers upward from the ends towards the middle to provide drainage ramps 16.Of course, these drainage channels and notches as shown in Figure 5e,f, g and h can be incorporated in any of the concrete members shown in Figures 5a through d.

Figures 6a through e illustrate 5 possibilities for the upper casting. That shown in Figure 6a is substantially the same as that shown in Figures 1 to 4. The example shown in Figure 6b has a plate into which a circular tubular collar 51 is partly recessed (into the surface of the plate) either by means of complementary screw-threads or as a press fit. In addition, the collar can be welded at its point of juncture with the bottom surface of the plate to provide additional security. The example of Figure 6c is intended for use when the socket provided for tilting of the upper concrete member relative to the lower concrete member is provided on the spindle.

In Figure 6c the steel plate includes a stub shaft 17, which may again be either solid or tubular, the lower end of which is rounded or chamfered. The top surface of the plate may be dished, (as shown) to allow for variations on the surface of the concrete member.

Figure 6d shows a steel casting which, on its upper surface has a lug 18 to fit countersinking on the upper concrete member 1, for example as shown in Figure 5d. The lug preferably includes one flat side for cooperation with the flat side in the countersinking of the concrete member 1 to prevent turning.

The socket 5 is provided integrally in the casting and is additionally supported by generally triangular-shaped strengthening webs 19. Preferably, the depth of the socket is less than one third the diameter of the socket.

The example shown in Figure 6e is again a steel casting, but this time the steel casting includes a stub shaft 171 and a lug 181 for cooperation with the concrete member 1.

Preferably, the length of the stub shaft is less than one third of its diameter and the stub shaft is again chamfered or rounded at its end.

Figure 7a shows substantially the same spindle as shown in Figures 1 to 4, but in this case the upper part 9 of the spindle also includes a screw-thread so that the nut can be screwed on to the position shown before it is actually welded to the solid tubular spindle.

Figure 7b shows an alternative in which the spindle includes a nut 111 welded to its top end, the nut being positioned so as to provide a socket for a stub axle extending from the upper plate or casting. Figures 7c and d show detail of a third possibility in which the socket is provided by an upper casting partly re cessed into the upper concrete member, the socket having both ends open so that the spindle can extend right through it and into a bore 20 also formed in the upper concrete member.The spindle has a reduced portion 91 which extends into the socket and which also enables the positioning of a pack of washers 21 on the top of the wider part of the threaded spindle, the shoulders provided at the narrowing of the spindle being chamferred or round to allow tilting of the spindle relative to the upper casting and thus tilting between the upper and lower concrete members.

Figure 8a shows a lower socket and plate substantially the same as shown in Figures 1 to 4. Figure 8b shows how the plate and socket can be formed by a steel casting which in cludes strengthening webs 22 as in the case of the upper casting. Additionally, a pair of aligned holes 23 can be formed in the sides of the socket so. that the extent to which the spindle has been screwed out of the socket can be judged. This might be achieved alternatively by forming a plastics patch on the spindle of a distinctive colour so that when the plastics material appears to the top of the socket the user knows that a given length of thread is still within the socket and that only a given number of further rotations is allowable before the threads of the spindle and socket are disengaged and thus unsafe.Alternatively a portion of the thread could be cut from the spindle which can be viewed to mark the length of the thread engaged. Figure 8b also shows that one or more of the strengthening webs can be provided with an aperture 231 for a tommy bar to be inserted to resist turning when the spindle is being rotated.

In Figure 8c there is shown an alternative steel casting which includes a lower lug 24 for cooperation with countersinking in the lower concrete member. Figure 9a shows a further possibility for the lower concrete member in which the top surface is countersunk 25 to receive a lug of the lower plate or casting (such as shown in Figure 8c) the lower member also including a pair of aligned bores 23 crossing the central bore through the concrete member to allow for sighting of the bottom of the spindle as it is rotated out of the socket.

Figure 9b shows a further possibility in which the socket is provided integrally with the lower concrete member, the threaded socket being tapped in a square bar 71 the flats of the square section providing resistance to move ment between the socket and the concrete member and also providing for the coopera tion of a spanner to resist turning of the lower concrete member when the spindle is rotated.

It will be appreciated that there are numer ous modifications which may be made to the various parts of the stool such that rocking of the spindle or stub shaft within the compile mentary socket is possible to provide for mis alignment between the upper and lower sur faces of the aperture cut in the wall.

WHAT WE CLAIM IS: 1. A stool for use in the construction of an in situ cast beam the stool comprising upper and lower body portions, the lower of which is arranged to be supported on the wall below and the upper of which is arranged to be used in load-bearing engagement with the wall above, and one of which includes a screw threaded socket having a vertical axis; and a screwthreaded spindle which screws through the screw-threaded socket and which includes means for enabling the rotation of the spindle relative to the screw-threaded socket, the other of the body portions or the spindle having an axially facing socket arranged to receive, respectively, the end of the spindle or the end of a stub shaft extending from the other body portion, with a clearance between the spindle or stub -shaft respectively and the surrounding wall of the socket whereby the other body portion may rock on the end of the spindle to allow the stool to adapt ,to:the shape of the wall above and below.

2. A stool according to claim 1, wherein the socket is-of short axial length.

3. A stool according to claim 2, wherein the axial length of the socket is less than or equal to one third of the diameter of the socket.

4. A stool according to any of the preceding claims, wherein the end of the spindle or the end of the stub shaft respectively has a chamfered or rounded edge to facilitate relative movement between the other body portion and the spindle.

5. A stool according to any one of the preceding claims, wherein the one body portion comprises a precast concrete member in which the screw-threaded socket is embedded.

6. A stool according to any one of claim 1 to 4, wherein the one body portion comprises a precast concrete member which is

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

steel casting, but this time the steel casting includes a stub shaft 171 and a lug 181 for cooperation with the concrete member 1.

Preferably, the length of the stub shaft is less than one third of its diameter and the stub shaft is again chamfered or rounded at its end.

Figure 7a shows substantially the same spindle as shown in Figures 1 to 4, but in this case the upper part 9 of the spindle also includes a screw-thread so that the nut can be screwed on to the position shown before it is actually welded to the solid tubular spindle.

Figure 7b shows an alternative in which the spindle includes a nut 111 welded to its top end, the nut being positioned so as to provide a socket for a stub axle extending from the upper plate or casting. Figures 7c and d show detail of a third possibility in which the socket is provided by an upper casting partly re cessed into the upper concrete member, the socket having both ends open so that the spindle can extend right through it and into a bore 20 also formed in the upper concrete member.The spindle has a reduced portion 91 which extends into the socket and which also enables the positioning of a pack of washers

21 on the top of the wider part of the threaded spindle, the shoulders provided at the narrowing of the spindle being chamferred or round to allow tilting of the spindle relative to the upper casting and thus tilting between the upper and lower concrete members.

Figure 8a shows a lower socket and plate substantially the same as shown in Figures 1 to 4. Figure 8b shows how the plate and socket can be formed by a steel casting which in cludes strengthening webs 22 as in the case of the upper casting. Additionally, a pair of aligned holes 23 can be formed in the sides of the socket so. that the extent to which the spindle has been screwed out of the socket can be judged. This might be achieved alternatively by forming a plastics patch on the spindle of a distinctive colour so that when the plastics material appears to the top of the socket the user knows that a given length of thread is still within the socket and that only a given number of further rotations is allowable before the threads of the spindle and socket are disengaged and thus unsafe.Alternatively a portion of the thread could be cut from the spindle which can be viewed to mark the length of the thread engaged. Figure 8b also shows that one or more of the strengthening webs can be provided with an aperture 231 for a tommy bar to be inserted to resist turning when the spindle is being rotated.

In Figure 8c there is shown an alternative steel casting which includes a lower lug 24 for cooperation with countersinking in the lower concrete member. Figure 9a shows a further possibility for the lower concrete member in which the top surface is countersunk 25 to receive a lug of the lower plate or casting (such as shown in Figure 8c) the lower member also including a pair of aligned bores 23 crossing the central bore through the concrete member to allow for sighting of the bottom of the spindle as it is rotated out of the socket.

Figure 9b shows a further possibility in which the socket is provided integrally with the lower concrete member, the threaded socket being tapped in a square bar 71 the flats of the square section providing resistance to move ment between the socket and the concrete member and also providing for the coopera tion of a spanner to resist turning of the lower concrete member when the spindle is rotated.

It will be appreciated that there are numer ous modifications which may be made to the various parts of the stool such that rocking of the spindle or stub shaft within the compile mentary socket is possible to provide for mis alignment between the upper and lower sur faces of the aperture cut in the wall.

WHAT WE CLAIM IS: 1. A stool for use in the construction of an in situ cast beam the stool comprising upper and lower body portions, the lower of which is arranged to be supported on the wall below and the upper of which is arranged to be used in load-bearing engagement with the wall above, and one of which includes a screw threaded socket having a vertical axis; and a screwthreaded spindle which screws through the screw-threaded socket and which includes means for enabling the rotation of the spindle relative to the screw-threaded socket, the other of the body portions or the spindle having an axially facing socket arranged to receive, respectively, the end of the spindle or the end of a stub shaft extending from the other body portion, with a clearance between the spindle or stub -shaft respectively and the surrounding wall of the socket whereby the other body portion may rock on the end of the spindle to allow the stool to adapt ,to:the shape of the wall above and below.

2. A stool according to claim 1, wherein the socket is-of short axial length.

3. A stool according to claim 2, wherein the axial length of the socket is less than or equal to one third of the diameter of the socket.

4. A stool according to any of the preceding claims, wherein the end of the spindle or the end of the stub shaft respectively has a chamfered or rounded edge to facilitate relative movement between the other body portion and the spindle.

5. A stool according to any one of the preceding claims, wherein the one body portion comprises a precast concrete member in which the screw-threaded socket is embedded.

6. A stool according to any one of claim 1 to 4, wherein the one body portion comprises a precast concrete member which is

supported on or supports a plate on which is provided the screw-threaded socket.

7. A stool according to any one of claim 1 to 4, wherein the one body portion comprises a precast concrete on which is supported or which supports a casting, with which the screw-threaded socket is integrally formed.

8. A stool according to claim 6, wherein the screw-threaded socket is provided by a nut welded to the steel plate in alignment with a hole through the plate.

9. A stool according to any one of the preceding claims, wherein the other body portion comprises a precast concrete member in which is embedded the socket for receiving the end of the spindle.

10. A stool according to any one of claims 1 to 8, wherein the other body portion comprises a precast concrete member on which is supported or which supports a plate on which is mounted the socket for receiving the end of the spindle.

11. A stool according to claim 10, wherein the socket is formed by a short length of tubing welded to the plate.

12. A stool according to any one of claims 1 to 8, wherein the other body portion comprises a precast concrete member which is supported on or which supports a plate to which is welded a stub shaft.

13. A stool according to any one of claims I to 8, in which the other body portion comprises a precast concrete member which is supported on or which supports a casting including integrally formed therewith the socket for receiving the end of the spindle.

14. A stool according to any one of claims 1 to 8, in which the other body portion comprises a precast concrete member which is supported on or which supports a casting which includes, integrally formed therewith, a stub shaft.

iA A stool according to any one of the preceding 'claims, wherein the means for rotating the spindle comprises a nut threaded on the spindle and fixed thereto.

16. A stool according to claim 1, wherein the socket for receiving the end of the stub shaft comprises a nut threaded partly onto the end of the screw-threaded spindle and fixed thereto.

17. A stool according to claim 1, wherein the socket is formed in the other body portion and is open at both ends, the spindle including a portion extending through the socket and having mounted thereon means for abutting the adjacent end of the socket to allow rocking of the other body portion relative to the spindle.

18. A stool according to claim 17, wherein the means abutting the end of the socket comprises an assembly of washers.

19. A stool according to claim 1, substantially as described with reference to Figures 1 to 4 or with reference to Figures l to 4 when modified by any of Figures 5 to 9 of the accompanying drawings.

20. A method of constructing an in situ cast beam in the wall of a building utilizing a number of stools in accordance with any one of the preceding claims, the method involving inserting and tightening the stools at hori zontally spaced portions in the wall and, with the intervening wall cut away, inserting reinforcement, errecting formwork, casting an in situ beam containing the reinforcement, and pinning up the wall above between the stools.

21. A method according to claim 20, substantially as described with reference to Figures 1 to 4 or with reference to Figures i to 4 as modified by any one of Figures 5 to 9 of the accompanying drawings.