GB2149874A

GB2149874A - Building structure

Info

Publication number: GB2149874A
Application number: GB08325376A
Authority: GB
Inventors: Roger Bailey
Original assignee: Norcros Investments Ltd
Current assignee: Norcros Investments Ltd
Priority date: 1983-09-22
Filing date: 1983-09-22
Publication date: 1985-06-19
Also published as: GB8325376D0; GB2149874B

Abstract

An assembly of a column 20, at least one beam 26 and a connector 24 comprises at least two plates (40) disposed in opposed faces of the column and four interconnecting elongate members (44) of square cross-section, each being welded to an area of each plate adjacent respective corners thereof. A cleat (24) is secured by bolts (47) to one of the plates (40) and to the elongate members, the bolts engaging in tapped bores (46, Fig. 3) in end portions of each elongate member. Each cleat comprises an angle member and a web (36) which fits into a recess 30 in an end portion of a beam 26 supported thereby. <IMAGE>

Description

SPECIFICATION Building structure This invention relates to building structures and in particular to precast beams and col umns and joint connections between such beams and columns.

In the manufacture of precast columns, moulds are used which are comparatively costly and it is desirable that they should be usable for a large number of casting operations. Provision has to be made for most columns to enable connection to transverse beams and connecting members therefore have to be applied to the side faces of the columns. The connectors, in some constructions, require that apertures should be cut in the walls of the moulds with the result that the number of castings will be limited to the specific columns required for a particular building.

It has already been proposed to provide a column connector which avoids the requirement for cutting the side wall of the mould but the prior proposal necessitates a connector which is relatively complex in an art where extreme simplicity with corresponding low cost is always the desired aim.

According to the present invention there is provided an assembly of a precast concrete column and at least one beam, the column having a recess in at least one face and the or each beam having an end rebate, square or rectangular plates mounted one within and forming a base surface of the or each recess, at least four elongate members rigidly interconnecting transversely of the column the spaced plates at respective points adjacent the corners of each plate, means defining screw threads at at least one end portion of each elongate member and aligned with a co-axial aperture in an adjacent said plate, at least one cleat member comprising a vertical plate portion and a horizontal plate portion, the horizontal portion supporting and being secured to the rebate of an associated beam and the vertical portion being secured by screw threaded means engaging the screw thread of a respective one of said elongate members, and lying within the corresponding recess of the column and the two portions being interconnected and reinforced by a web, and means incorporated in the end portion of the associated beam defining a downwardly-opening slot which accommodates the web of the corresponding cleat member and provides the securing points operative between the beam and the cleat member.

Further according to the present invention there is provided an assembly of a precast concrete column and at least one beam, the column having a recess in at least one face, the or each beam having an end rebate, at least two square or rectangular plates one mounted within and forming a base surface of the or each recess, at least four square-section bars interconnecting the plates and passing transversely through the column, the bars being spaced from respective adjacent edge boundaries of the plates, means defining at least four screw threads secured to each plate, at least one cleat member the or each being secured to a respective plate by further means defining screw threads mating with said at least four screw threads, the or each cleat member comprising a vertical plate portion, a horizontal plate portion and a triangular web reinforcing and interconnecting the vertical and horizontal portions, the vertical portion being secured by said further screw means and the horizontal portion serving to support and be secured to the rebate of a said beam and the vertical portion lying within the corresponding recess of the column, and means incorporated in the end portion of the or each beam which define a downwardly-open slot which accommodates the web of the corresponding cleat member and which define seatings and securing points for the horizontal portion of the or each cleat member.

Building structures embodying the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is an exploded isometric view illustrating one embodiment of a column and associated beams in accordance with the invention: Figure 2 is an elevation of an assembly in accordance with the invention providing for the connection of four beams; Figure 3 is a plan view of the assembly of Figure 2; Figure 4 is a section on the line 4-4 of Figure 3; Figure 5 is a plan view of a washer forming a part of the assembly of Figures 1 to 4; Figure 6 is an end elevation of an assembly which is incorporated in an end portion of a beam which is to be included in the main assembly.

Figure 7 is a side elevation of the subassembly of Figure 6; Figure 8 is a plan view of the sub-assembly of Figure 6; and 9 to 13 are plan views of various forms of connector core of the assembly.

The building structure in accordance with the invention is illustrated in outline in Figure 1 which is an exploded view illustrating a column and end portions of two beams together with parts of a connector assembly.

The column 20 is provided on opposite faces with recesses 22 and each recess will accommodate a seating cleat 24 shown in detail in Figures 2 and 3. It will be noted that the recesses do not necessarily extend across the full transverse dimension of the corresponding face of the column.

Each beam has at its end mounted on the column through the cleat, a rebate or step 28 and a recess or slot 30 of substantially inverted U section which is defined by angles and a strip plate illustrated in Figures 6 to 8.

When assembled together the recess 30 accommodates a web 36 of the cleat 24 and the connection will be completed by bolts (not shown) passing through elongate apertures 38 in the cleat and engaging in tapped sockets 32 welded to flanges 34 of angle members 35. The recess defining assembly is completed by U-shaped bars 37, 39 which serve both to hold the angle members 35 together and to serve as local reinforcement in the concrete of the end portion of the beam.

The vertical limbs of the angle members are also interconnected by an inclined strip plate 41, which in the assembled condition extends parallel to an inclined free edge of the web 36.

Turning now to the connector illustrated in Figures 2, 3 and 4, each connector comprises four end plates 40 having four holes 42 (broken lines) and to the inwardly facing face of each plate 40 square or rectangular section bars 44, 45 or other elongate members are welded, these bars serving both to interconnect the plates 40 and to provide tapped, blind, bores by which bolts 47 serve to secure the cleats 24 to the plates 40. The tapped portion of each bar is indicated at 46. The bars 44 directly connect two plates 40 whereas bars 45 are welded to side faces of respective bars 44. The bars 44 (four as shown in Figures 2, 3 8 4) are interconnected in pairs by plates 49.

The connection member just described is thus of extreme simplicity as the interconnecting bars serve a dual purpose and, moreover, because they are spaced apart over the area of each plate 40 excellent rigidity is provided.

Moreover, a degree of redundancy is involved in as far as the failure for any reason of one connecting bar 44,45 and associated welds will not result in failure of the connector as a whole. Weld fillets extend wholly around each bar 44, 45 at the location where it meets the inner face of each plate 40. As an alternative to square-section bars 44, 45 the connectors may be tubular and the tapped threads 46 for the bolts will then extend a part way only along the hollow interior.

Each cleat 24 is essentially an angle section member of which the rigidity is increased by the web 36. A gap 50 is provided at the internal corner of the angle section member to ensure proper seating of the edges of the web during assembly and welding. The vertical limb of each cleat has four holes aligned with respective holes 42 in the plates 40.

Figures 2, 3 and 4 illustrate a column 52 (chain lines) together with four cleats 24. The presence of a generally conventional reinforcement cage 54 (chain lines) is indicated in the column in Figure 3. The latter will, in practice, be spaced from the connector assembly and cleats will normally be spaced from those of the next connector assembly by the height of one storey of a building. As will be apparent, each plate 40 is embedded in the material of the column and forms the base surface of the recess 22 illustrated in Figure 1.

The slots 38 of each cleat allow for connection to the horizontal undersurface of the rebate 28 of a beam by bolts 39 whilst making allowance for tolerances. The bolts 39 have heads which cooperate with plate washers 41 which are each welded to a loop of wire 43, which acts as a reinforcement for grouting in the final assembly of column and beam or beams. It will be apparent that the recesses 22 of the column terminate at their upper and lower ends in chamfers 80 and that the vertical portions of the vertical limb of each cleat lies fully within the confines of the respective recess.

In general terms the simplicity of the construction is readily apparent. With the embodiment of Figures 2, 3 and 4 the problem of accommodating orthogonal beams is overcome by the direct and indirect connection of the plates 40 by the bars 44, 45. By constructing the recess 24 so that it does not extend across the full width of the column location. A vertical joint line of the column can be provided on the external face elevation.

Figures 1 to 5 illustrate the relatively complex assembly with four cleats and four beams. Figures 9 to 1 3 demonstrate the flexibility of the basic connector assembly which as seen in Figure 9 serves to support only one cleat and beam, in Figure 10 serves to support two opposed cleats and beams in Figure 11 serves to support two orthogonal cleats and beams, in Figure 1 2 serves to support three cleats and beams and in Figure 1 3 (as in Figures 2 to 4) serves to support four cleats and beams. In the Figure 9 construction, it will be noted that the right hand plate 40 (as illustrated) is not accomodated in a recess such as 24 (Fig. 1) but is embedded in the material just below the surface of the column.

The basic connector assembly remains essentially the same irrespective of the number of beams secured to the column. The square section members 44,45 facilitate welding in contrast to interconnecting members of other sections since a squared off end of one member can readily be made to butt another member or plate with high accuracy.

Claims

1. An assembly of a precast concrete column and at least one beam, the column having a recess in at least one face and the beam or each beam having an end rebate, square or rectangular plates mounted one within and forming a base surface of the or each recess, at least four elongate members rigidly interconnecting transversely of the column the spaced plates at respective points adjacent the corners of each plate, means defining screw threads at at least one end portion of each elongate member and aligned with a co-axial aperture in an adjacent said plate, at least one cleat member comprising a vertical plate portion and a horizontal plate portion, the horizontal portion supporting and being secured to the rebate of an associated beam and the vertical portion being secured by screw threaded means engaging the screw thread of a respective one of said elongate members, and lying within the corresponding recess of the column and the two portions being interconnected and reinforced by a web, and means incorporated in the end portion of the associated beam defining a downwardlyopening slot which accommodates the web of the corresponding cleat member and provides the securing points operative between the beam and the cleat member.

2. An assembly of a precast concrete column and at least one beam, the column having a recess in at least one face and the or each beam having an end rebate, at least two square or rectangular plates one mounted within and forming a base surface of the or each recess, at least four square-section bars interconnecting the plates and passing transversely through the column, the bars being spaced from respective adjacent edge boundaries of the plates, means defining at least four screw threads secured to each plate, at least one cleat member, the or each being secured to a respective plate by further means defining screw threads mating with said at least four screw threads, the or each cleat member comprising a vertical plate portion, a horizontal plate portion and a triangular web reinforcing and interconnecting the vertical and horizontal portions, the vertical portion being secured by said further screw means and the horizontal portion serving to support and be secured to the rebate of a said beam and the vertical portion lying within the corresponding recess of the column, and means incorporated in the end portion of the or each beam which define a downwardly-open slot which accommodates the web of the corresponding cleat member and which define seatings and securing points for the horizontal portion of the or each cleat member.

3. An assembly according to claim 1 or claim 2 comprising four said plates the two additional plates being accommodated in corresponding recesses of the column, the additional plates being secured to further transverse bars which are secured to the firstmentioned bars and the further transverse bars having screw threads enabling them to be secured to the vertical portions of further said cleat members.

4. An assembly according to any one of the preceding claims wherein the means defining a downwardly-facing slot in the end of each beam supported by the said column comprises the angle members with vertical limbs adjacent and interconnected by an inclined plate, horizontal limbs extending away from one another but lying in a common plane and internally screw-threaded members upstanding from the upper faces of each horizontal limb.

5. An assembly according to claim 4, wherein the horizontal limbs are welded to a reinforcing rod loop which is embedded in the concrete of the associated beam.

6. An assembly according to claim 4 or claim 5, wherein each vertical limb carries and is welded to a vertical loop which is embedded in the concrete.

7. An assembly of a precast concrete column and at least one beam, substantially as hereinbefore described with reference to the accompanying drawings.