WO1983001269A1

WO1983001269A1 - Precast concrete frameworks

Info

Publication number: WO1983001269A1
Application number: PCT/GB1982/000289
Authority: WO
Inventors: Mac Concrete Limited Dow
Original assignee: Taylor, Howard, Peter, John
Priority date: 1981-10-09
Filing date: 1982-10-08
Publication date: 1983-04-14
Also published as: IE53717B1; FI831975A0; EP0090023A1; IE822440L; FI831975L; DK259983A; DK259983D0

Abstract

A precast, reinforced, concrete member (11), intended when in situ to be orientated vertically, the member (11) having a transverse metal insert (10) receiving a load-supporting billet or other member (18). The billet supports a beam (14). The insert (10) preferably has a square section and is rigid with the reinforcement cage. The use of the insert avoids the necessity to cut holes in a mould member which are otherwise necessary to accommodate tranverse, integral, members necessary to support a beam.

Description

PRECAST CONCRETE FRAMEWORKS

The invention relates to precast concrete frameworks. Precast concrete frameworks for use in building and other constructions generally include columns, floor members and beams. Because of architectural and other requirements beams are joined to columns at different points along the lengths of the column depending upon the height of the individual stories of the building. With conventional joints between beams and columns, the column is generally provided with projecting members to enable the beams to be secured thereto and it follows that moulds must be prepared having apertures along their lengths to accommodate the required spacing of the projecting members. Precast concrete moulds are costly and the preparation of specific moulds for each building project has an adverse effect upon the overall cost of the columns. According to the present invention there is provided a precast concrete member, intended when in situ, to be orientated vertically, such as a column or a wall, said member having at least one transversely-extending insert and a load-supporting member received in the insert and and projecting therefrom, so that, when assembled a load such as a beam can be supported therefrom.

Further according to the present invention there is provided a precast concrete member, intended when in situ, to extend vertically, such as a column or a wall, said member having a plurality of recesses spaced over its vertical extent, the surface, defining each recess being formed with at least one transverse aperture accommodating a hollow insert, the inserts each receiving a metal billet projecting therefrom to provide support for a structure carried by said precast concrete member.

.Still further according to the present invention there is provided a precast concrete member, intended when in situ, to have a vertical extent, said member being cast with spaced transverse, hollow, inserts along said vertical extent, each said insert being capable of receiving a transverse member which serves to support a beam or other structural member.

The invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings in which:

Figure 1 is a side elevation showing a column in accordance with the invention at a joint with a transverse beam;

Figure 2 is a section on the line II-II of Figure 1; Figure 3 is a plan view of. the column; Figure 4 is cross-section of a modified billet forming a part of the joint; and

Figure 5 is fragmentary section of a double T beam in accordance with the invention. In order to manufacture a column for use in a joint in accordance with the invention, a conventional mould of prismatic cross-section is provided but it is possible to omit entirely any apertures in the side walls of the mould which would, hitherto, be required to accommodate projecting members providing a basis for a joint with a transverse beam. The mould may include facilities to enable prestressing of the reinforcement or simply means of a conventional nature suitable to locate the reinforcement within the mould prior to concrete pouring. A transverse, square cross-section, insert 10 is located within the mould by clips (not shown) supported by the mould side walls and these clips and inserts are located at required positions where beam joints will be formed in the complete structure. The insert may be welded or otherwise secured to the reinforcement if the column is not to be prestressed and if this modification is provided the overall load-bearing capabilities will be increased.

As will be apparent particularly from Figure 1, the column 11 is formed with recesses 12, at the joint locationregions which will enable the beam 14 of the inverted T section in the completed joint to lie with its end closely adjacent the line of the vertical edge 16 of the column. It will be apparent that the mould will require no modification to accommodate different spacings between joints and the cost of cutting joint member receiving apertures is avoided. Turning now more particularly to the accompanying drawings showing a joint in accordance with the invention when in situ, the insert 10 receives a steel billet or other member 18 of hollow, square, section complementary to the internal cross-section of the insert; if corrosion is unlikely to arise the billet 18 may be loose in the insert although if corrosion is probable then it will be secured either by an appropriate adhesive, by welding or grouting. The billet may be solid as shown in Figures 1 and 2.

To provide a top connection to the beam, a transverse circular section aperture 19 is provided at an appropriate spacing above the insert 10.

The beam has at the end illustrated a lower recess 20 and an upper recess 22 and, as shown, the lower recess has a plate 24 defining its uppermost, horizontal, boundary and this rests on one projecting end portion of the billet. The other portion of the joint is completed by a plate 26 resting in the lowermost, horizontal, boundary of the upper recess 22 whichas shown is secured by welding to one end of reinforcing rods 28 and the plate has a blind hole receiving a tapped bush 30 to which a bolt 32 is screwed in order to retain an angle section member 34 which is secured by a further bolt 36 and a tapped bush 38 at either end of the upper circular cross-section aperture in the. column. More than one bolt and corresponding bush is provided in each limb of the angle section member 34. The billet 18 may be of solid mild steel or of hollow section. If a hollow section is selected, the passage may be filled with concrete 40 as shown in Figure 4. In order to ensure, particularly during erection of a structure that the billet and associated beam are conveniently packed to line and level, particularly beams requiring two billets at each end, the billet as shown in Figure 4 has two aligned apertures 42, 44 which receive a mild steel tube 46 which is tapped internally and this in turn receives a grub screw 48.

The apertures 42, 44 are ^:countersunk to facilitate fillet welding at 50. The welds are ground flush to enable smooth insertion and adjustment of the billet in the insert 10. The grub screw 48 enables the billet to be positively engaged with a beam immediately the latter is placed in situ. The grub screw 48 will be turned so that it moves upwardly and the projecting portion will engage in an aperture in the plate 24 and in a recess in the underface of the beam 14. The grub screw can also be used to provide a fine, levelling, adjustment of the beam. Although the invention has been described primarily in relation to precast concrete columns, it is also possible to incorporate inserts and billets in other vertical structures. One example of such a structure is a doubletee beam which is used as a wall.,unit. Such beams have two parallel ribs and a single wide flange having an extent in accordance with loading and or space requirements. The moulds for such beams are costly and since it is conventional practice to prestress the reinforcement, the natural shortening of the beam on removal of the initial stress makes it very difficult, as well as costly because of the need to cut the mould, to incorporate projections which serve to support other parts of the structure such as floors, lintels and so on.

Figure 5 illustrates the use of inserts 10 incorporated in a rib 52 and a transverse flange 54 of such a Tee beam. As will readily be seen the inserts are welded to the reinforcement rods 56 and hence accurate location will be provided without any measures incorporated which are additional to those conventionally used for locating reinforcement within moulds. Although in the description hereinbefore set forth, the inserts are shown singly, it will be appreciated that such inserts can be provided at given locations in groups, so that beams extending at right angles to one another can be supported. The inserts will then be welded together initially before incorporation into the reinforcing cage or cages. The inserts and corresponding billets may have sections other than the square section illustrated.

The provision of a separate reinforcing member cage to support and firmly anchor the insert or inserts is possible and will be desirable where the pre-cast concrete member is also pre-stressed.

Recesses as shown at 12 ensure that beams mounted in the billets cannot twist under load.

The cost savings for moulds by use of the construction in accordance with the invention are considerable and especial advantage is gained with a cast concrete member having a pre-stressed reinforcement.

Claims

1. A precast concrete member, intended when in situ, to be orientated vertically, such as a column or a wall, said member having at least one transversely-extending insert and a load-supporting member received in the insert and projecting therefrom, so that when assembled a load such as a beam can be supported thereon.

2. A precast concrete member, intended when in situ, to extend vertically, such as a column or a wall, said member having a plurality of recesses spaced over its vertical extent, the surface defining each recess being formed with at least one transverse aperture accommodating a hollow insert, the inserts each receiving a metal billet projecting therefrom to provide support for a structure carried by said precast concrete member.

3. A precast concrete member, intended when in situ, to have a vertical extent, said member being cast with spaced transverse, hollow, inserts along said vertical extent, each said insert being capable of receiving a transverse member which serves to support a beam or other structural member.

4. A member according to claim 1, claim 2 or claim 3 wherein the or each insert is of metal.

5. A member according to any one of the preceding claims wherein the or each insert is positively held in the precast concrete member.

6. A member according to any one of the preceding claims wherein the insert and the billet or other transverse loadsupporting member received therein are of square crosssection.

7. A member according to any one of the preceding claims wherein the billet or other transverse, load-supporting member incorporates means enabling poεitive engagement with a supported beam or other transverse structural member.

8. A precast concrete member in accordance with any one of the preceding claims in the form of a double T beam used as a column or wall section.

9. An assembly including a vertical precast concrete member and a beam or other structural member carried by the precast member, said concrete member having at least one transversely-extending, hollow, insert receiving a transversely-extending member projecting beyond the insert so as to support an end portion of said beam or other structural member.

10. An assembly according to claim 9 wherein the or each insert of the concrete member lies within a portion thereof, of reduced transverse dimension.

11. An assembly according to claim 9 or claim 10 wherein the or each transversely-extending member engages in a recess of the beam or other structural member.

12. An assembly according to claim 11 wherein contact between the transversely-extending member and the beam is through a metal plate.

13. An assembly according to any one of claims 9 to 12, comprising an auxiliary support connection between the transversely-extending member and the vertical, precast member.

14. An assembly according to claim 13, wherein the auxiliary support connection comprises a transverse member extending through and secured to the vertical concrete member, an angle member secured to said transverse member and a tapped bush welded to reinforcement of the beam, said angle member also being secured to the tapped bush by a bolt.

15. A method of manufacturing a pre-cast concrete member intended for vertical orientation when in situ and having transverse support means for carrying a beam or other transverse member, said method comprising the steps of providing a mould, locating a reinforcement cage within the mould, locating a hollow, metal, member within the mould with ends thereof within the outline of the mould, pouring the concrete mix into the mould, allowing the concrete to harden sufficiently to enable removal of the mould and subsequently inserting a transverse metal member into said hollow metal member such that the former extends beyond the latter and provides the support means for the beam or other transverse member.

16. A precast concrete member substantially as hereinbefore described with reference to the accompanying drawings.

17. An assembly of a precast concrete member and a beam or other structural member substantially as hereinbefore described with reference to the accompanying drawings.