Lift slab support assembly

Sept. 23, 1969

3,468,084

F. VAESSEN

LIFT SLAB SUPPORT ASSEMBLY

Filed May 31, 1967

Sheets-Sheet 1

<img file="US3468084A_D0001.tif" />

FIG. I

INVENTOR.

XWZ MESSEV

BY

ATTORNEYS

Sept. 23, 1969

3,468,084

F. VAESSEN

LIFT SLAB SUPPORT ASSEMBLY

Filed May 31, 1967

Sheets-Sheet

<img file="US3468084A_D0002.tif" />

FIG. 2

<img file="US3468084A_D0003.tif" />

FIG.3

INVENTOR.

/fiANZ MESSEM

BY attorneys

3,468,084

Patented Sept. 23, 1969

United States Patent Office

3,468,084 LIFT SLAB SUPPORT ASSEMBLY Franz Vaessen, Essen, Germany, assignor to Fiona Hochtief A.G. fur Hoch-und Tiefbauten vorm. Gebr. Helfmann, Essen, Germany

Filed May 31, 1967, Ser. No. 642,493 Claims priority, application Germany, July 23, 1966, H 60,056 Int. Cl. E04b 1/35,1/34,1/18

U.S. Cl. 52—126 5 Claims

ABSTRACT OF THE DISCLOSURE

An assembly for supporting a lift slab on a column where the slab has an opening through it so that it can be moved upwardly along the column to its support position. Support brackets are integrally secured to the column and arranged thereon so that the slab will pass over the brackets when being lifted and will rest on them when in its support position. A frame member forms the opening through the slab, and slotted slab support plates are attached to the frame member and extend above the support brackets when the slab is in its support position on the column. A support device bears on the support brackets and supports the support plates of the frame for transferring the slab load to the column. The support device has adjustable means such as wedge-like shims for accurately locating the slab in its support position, the wedge-like shims are self-locking when the slab is set in position.

Summary of the invention

This invention is directed to a support arrangement for a lift slab construction and, more particularly, to a support arrangement wherein an adjustable support device transfers the slab load from a support member secured to the slab to a support bracket mounted on a column.

In the past, in the construction of reinforced concrete floor slab-type buildings, each floor was constructed in its final support position whereby buildings of considerable height posed a number of problems. The lifting and placing of concrete at a height above the ground is more difficult and expensive than if performed at ground level and also involves a number of safety consideration. Building the floor slab forms at ground level is simpler as are various other tasks involved in the construction of such slabs.

In recent years, to overcome the problems of erecting the concrete floor slabs in place, a new construction method was developed for building the floor slab at the base of a building and then lifting it upward along the columns which are to support it until the slab is located in its support position. Accordingly such buildings have been characterized as being of the “lift-slab type.” In liftslab type buildings each floor is built at the base of the building, generally at grade level, and after its forms have been stripped and the slab has set, it is lifted upwardly along the building support columns and placed in its support position on the columns. When they are being constructed, openings are formed in the slabs around the vertical support members or columns so that the slabs can be lifted upwardly into position without any interference as they rise along the vertical support members.

Various devices have been used to support the lift slabs from the vertical support structures. Usually the slab is constructed so that it has a collar or frame forming the opening in the slab, and the frame is supported on a support member attached to the vertical support. In an arrangement of this kind, presently in use, the support on the vertical support member or column is a strut-like or knee brace type support construction which is connected to the column by an articulated joint so that it can be moved out of the plane of the slab as the slab is moved upwardly along the column. When the slab is located in its support position, the support can then be moved into position below the slab. This particular arrangement has several disadvantages: (1) it is costly, (2) it does not permit exact adjustment of the elevation height of the slab, and (3) misalignment and tolerances arising out of constructional inaccuracies cannot be compensated for easily. Further, the use of a support member which is moved or swung into support position provides difficulties in assembly, particularly where assembly takes place at the field site as is the usual case in building construction.

The primary object of the present invention is to provide a support device for a lift slab which permits exact adjustment of the elevation or support position of the slab on its vertical support member.

Another object of the invention is to afford a support means on the vertical support member which does not interfere with the lifting of the slab into position and does not have to be moved or extended into position to support the slab.

Still another object of the invention is to provide a support arrangement for the slab which is simply and easily assembled and includes adjustable means for the exact elevational positioning of the slab.

Accordingly, the present invention provides an assembly of parts for supporting a lift slab in its support position on a vertical support member or column. To permit the lift slab to be moved vertically from the position where it was constructed at the base of the column to its support position on the column, it is necessary to afford an opening through the slab so that it can be moved without interference along the column. The opening is formed by a frame member which supplies an opening of sufficient size for the lifting operation and an adequate structure for the transfer of the slab load to the column member.

On the support column, a support bracket is secured to carry the slab member in its support position. Additionally, slotted support plates are securely attached to the frame member. When the slab member is placed in its support position on the column, this usually requires the frame member to move past at least a portion of the support bracket, an adjustable support device is interposed between the support bracket and the support plate fitting into the slots in the plates. The support device rests on the support bracket and carries the support plates for transferring the load of the slab to the column.

The support bracket or seat is integrally attached to the column and is of sufficient width to provide an adequate surface to support and transfer the slab load to the column. Similarly, the support plates are integrally attached or welded to the frame and are also of a sufficient cross section to adequately transfer the slab load. It will be appreciated that these parts, in addition to carrying the dead load of the slab, must also be of sufficient structural strength to transfer any of the live loads carried by the slab. The live load on the slab can vary considerably depending on the type of use to which the floor slab is exposed.

The support device for transferring the slab load from the plates on the frame to the brackets on the column comprises a bar or plate member which is supported directly on the support bracket and adjustable members, such as wedges or cotters, which are inserted into the slots in the plates. The adjustable members are in supporting contact with the plates on the frame and rest on the plate member of the support device. It will be appreciated that it is easier to insert the adjustable members into the top of the slot in the plate, however, it is also possible to posi3,468,084 tion them below the plate member of the support device bearing on the support bracket. The adjustable members are self-locking when they are inserted into the slot. Further, because of the dimensional variations which develop during the construction of the slab and of the various parts of the support assembly, certain tolerances occur which are compensated for by the use of the adjustment members. Accordingly, a multiple shim arrangement can be used at these locations to take up any tolerances that might be developed. It can be appreciated that the use of the adjustable members supplies a simple and easily assembled means for setting the lift slab in its exact elevational position. Further, since the adjustable means are inserted above the slab, no special equipment is required to place the slab in its support position.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated and described a preferred embodiment of the invention.

Brief description of the drawings

In the drawings:

FIG. 1 is a perspective view of a lift slab and support column embodying the support arrangement of the present invention;

FIG. 2 is a sectional side view of the support arrangement shown in FIG. 1, taken along line A—A; and

FIG. 3 is a sectional side view of the arrangement shown in FIG. 1 taken along line B—B.

Detailed description

In FIG. 1, there is shown a horizontally disposed lift slab 1 in its support position on. a vertical column 3. Originally, the lift slab is constructed at the base of the support column 3 and is provided with a cutout or opening formed by a frame member comprising a horizontally arranged flange 4 and a vertically upstanding wall 5 which form the periphery of the opening 2. A plurality of vertically arranged stiffener members 5a are secured to the flange and to the walls 5 to provide additional support for the frame member. The opening formed through the slab is of a sufficient size to permit the slab to be lifted upwardly along the column so that its passage is not interrupted by any structure secured to the column.

At the support position of the slab on the column 3, support brackets 6 are integrally attached, as by welding, to the column. In FIG. 1 it will be noted that the support brackets are welded to the outer edges of the column flanges, however, they could be positioned on other parts of the column surface. Further, though the column shown in FIG. 1 is an I-beam structural shape, other standard or built-up structural shapes could also be used.

At each corner of the frame member a vertically arranged plate member 7 is welded to the walls 5. The plate members 7 extend above the top of the frame and have vertically extending slots 8, the upper ends of which are spaced below the upper ends of the plate members 7.

Extending transversely across the flanges of the column is a support device resting on the support brackets 6 and supporting the plate members 7. The support device comprises a support bar 10 which is positioned within and extends from the slot in one of the plate members 7 across the width of the column 3 into the slot in the oppositely arranged plate member 7. Along its lower edge surface, the support bar rests on the support brackets 6. As can be seen in the drawing, the upper edge surface of the support bar 10 is spaced below the top of the slots in the plate members 7 providing an open space therebetween. Within this space adjustable support means 9 are positioned comprising wedge-shaped shim members which take up the difference between the top of the bar and the top of the slot. Due to their shape, once the shim wedges are in place and have transferred the load from the plates to the bar 10, they are locked in position and cannot be easily removed. While the adjustable support means 9 are shown as shim wedges, it will be appreciated that other types of cotters or keys could be used to supply the same function.

In practice, after the slab has been constructed, it is lifted from its position at the base of the column 3 to its support position on the column. With the slab held in position, the support bar 10 is inserted through the slots 8 in the plate members 7 and rests at its lower edge surface on the support brackets 6. Next, to establish the slot surface at its proper elevational level, the adjustable shim wedges 9 are driven into the slots 8 between the top of the support bar and the top of the slot until they are finally locked in tightly fitting position. Accordingly, the weight or load of the slab 8 is transferred through the shims 9 and the bar 10 from the plate members 7 to the support brackets 6 on the column 3. After the slab is secured in its support position, the opening 2 is filled with concrete enclosing the various elements of the support assembly and protecting them from corrosion.

By this arrangement the life slab is easily and safely supported on the support brackets 6. Since the support bracket is integrally attached to the column and does not have to be moved or repositioned when the slab is in place, the bracket overcomes the problems faced by the prior art. Additionally, the device for supporting the slab on the column is easily assembled, it assures the exact height adjustment of the slab, and it does not require any special equipment for the insertion of the support device to transfer load.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.