METHOD AND DEVICE FOR FIXING THE BOTTOM END OF A COLUMN TO CAST BASE PLATE

Abstract: The invention relates to a method and a device for casting the bottom end of a column (1) into a fixing position in a column excavation (3) produced by casting of a base plate (2). In so doing itis ensured that the column is given a predetermined adjustment level in the column excavation (3). A metal mesh cage (4) serving as casting mould is used in order to produce the column excavation (3). The cage (4) is placed so that it encloses the fixing position and is fixed by casting of the base plate in interlocking engagement therewith. In order to produce the predetermined adjustment level a levelling compound (5) is introduced into the column excavation (3) up to the adjustment level. The levelling compound (5) is allowed to set and when the column (1) is to be cast in its bottom end is placed on the setting levelling compound (5) in the fixing position, following which the column (1) is finally cast in starting from the support afforded by the levelling compound (5).

Description: Method and device for fixing the bottom end of a column to a cast base plate The present invention relates to a method and a device for fixing the bottom end of a column in a fixing position to a cast base plate according to the pre-characterising parts of the independent claims. Fixing a column to a cast base plate made of concrete, for example, was already previously known. In this case bolts are commonly used to fix the column to the plate. The said bolts require precise fitting both in the right position and at the correct angle in order to get the upright correctly located and to be able to fit the upright easily over the bolts. In order to then level the upright correctly nuts are generally used, which are screwed on to the bolts and a column foot with matching bolt through-holes welded on to the column. The level of the column can then be adjusted by means of the nuts. In order to subsequently fix the column further nuts are screwed on to the bolts on top of the column foot, so that the column foot is clamped fast between its overlying and underlying nuts. Column fitting on a building site, for example, is often carried out some time after fastening of the bolts, which carries a risk of the threaded parts of the bolts being damaged during the building work due to spattering, collisions or the like. Another common method of fixing a column to a cast base plate is to fix a steel attachment, to which a steel column can subsequently be welded fast. In this case the column must be cut to the right length before welding, in order to bring the upper end of the column to the correct level. Welding results in a build-up of stresses in the steel and adversely affects the rust protection and any other surface coatings on the column. The welding work is also dependent upon the weather and constitutes a potential fire hazard. There are not normally any welders present on a building site, for example, so that welding will mean that a further trade category has to be called in for this particular work. Since the base plate is cast some time before the columns are fixed, this means that the fixing point has sometimes to be adjusted for height and/or lateral position, which with the above-mentioned fixed bolts or fastenings can be accomplished only with difficulty. A column foot and bolts as described above take up a certain amount of space on the base plate around the column, which results in inconvenience if there are any building works in progress in this area. Reference will also be made to the BUILDING Manual, Main Section c, Building Construction Technology, published by AB Byggmastarens Fδrlag, Stockholm 1964 and the Manual of Prefabricated Construction Volume II, published by Bauverlag GmbH, Wiesbaden-Berlin 1967. The first aforementioned publication shows the assembly of columns in column excavations, the columns being levelled by means of a plate and an adjusting screw. The second publication describes how a column is centred in relation to a steel plate and is held fast by wedges until it is cast in. An object of the present invention is to produce a device and a method by means of which the problems described above can be eliminated or at least reduced. According to the present invention a method is created for fixing a column to a cast base plate according to claim 1. According to the present invention a device is also created for fixing a column to a cast base plate according to claim 6. Preferred embodiments also have any or some of the characteristics specified in the subordinate claims. The invention will be explained below with reference to the attached drawing, which shows examples of embodiments of the device according to the present invention. Fig. 1 shows a cut-away diagram of a base plate with a column excavation and an inserted column end fixed by means of a fixing compound. Fig. 2 shows a column end of a square tube with notches Fig. 3 shows a column end of an H-girder with notches Fig. 4 shows a column foot for the column according to figure 2 Fig. 5 shows a column foot for the column according to figure 3 Fig. 6 shows a cap for covering the column excavation Figure 1 shows a column 1 in a cast base plate 2. The bottom end of the column 1 is located in a fixing position, which is enclosed in a column excavation 3. A mould 4 defines the boundary surfaces of the column excavation 3 in relation to the base plate 2. In the column excavation 3 and beneath the column 1 there is a levelling compound 5 and on top of the levelling compound 5 there is a fixing compound 6. The column excavation 3 is produced by casting of the base plate 2 in that the mould 4 is placed in such a way that it contains the intended fixing position of the column 1 in the casting mould for the base plate 2. The mould 4 retains the casting compound whilst the casting compound of the base plate 2 is setting. The mould 4 might be formed, for example, from a metal mesh cage, which with its openings and irregularities in the surface provides not only good adhesion for the casting compounds but also the facility for the introduction, for example, of a lashing wire, a steel reinforcement or a cable duct. The horizontal extent of the column excavation is advantageously many times greater than the cross-section of the column, so that the horizontal position of the column can be adjusted after casting of the base plate 2. By means of this method a facility for horizontal adjustment of the fixing position is maintained for as long as possible, that is to say until such time as the column 1 is fixed. The vertical adjustment is performed by pouring levelling compound 5 into the column excavation 3 up to a desired level and allowing it to set. The column 1 is then fixed starting from the support afforded by the upper surface of the levelling compound 5. The levelling compound is designed to flow out and form an even horizontal plane for the column 1 and is preferably composed of free-flowing concrete. In alternative embodiments the levelling compound is composed of some other suitable material, for example sand. Different examples of columns according to the invention are shown in figure 2 and figure 3. The column 1 is preferably made of steel and has a cross-section comprising plane sides, but may also be made of other metal or have some other cross-section, for example a circular one. Figure 2 shows a column 1' of square tube with a bottom surface 7 and notch 8, together with a through-opening 9 at a distance from the bottom surface 7. The notch 8 is formed from the bottom surface of the column in the longitudinal direction of the column and results in a 10-90% reduction of the distal bottom surface 7, preferably one of approximately 50%. When the column 1 is placed on a plane surface, therefore, only parts of the original bottom surface 7, preferably at the four comers of the column, will have contact with the plane surface, which reduces the possibility of sand, gravel and other material getting between the bottom surface 7 and the plane surface, which might give the column an angle error. The notch 8 also serves as the space for the fixing compound 6, which means full contact between the levelling compound 5 and the column 1, even if sand, gravel or other material should be present in the space. The increased size of the notch 8 also increases the sum of the distal bottom surface 7 of the column and the surface of the notch 8, which means that the column fixing is capable of bearing an increased load. The notch 8 together with the through-opening 9 also forms a passage through the column for the fixing compound 6. The column in figure 3 has substantially the same characteristic features as the column in figure 2. A further application of the through-opening 9 is that together with a bar (not shown) it can counteract lifting forces in the column. A centre part of the bar is located in the through-opening so that the ends of the bar extend on either side of the column 1. When the bar is fixed in the fixing compound 6 the bar will counteract lifting forces in the column. Whilst the fixing compound is setting the column is supported by braces (not shown), which are usually fixed to the column by known methods at a suitable height above the base plate 2. Examples of a column foot 10 are shown in different embodiments in figures 4 and 5. Located between the column 1 and the levelling compound 5, the column foot 10 provides a guide and a support for the column 1. A further function of the column foot is to distribute forces from the column 1 to the levelling compound 5. When the fixing compound sets the column 1 and the column foot 10 are fixed. That portion of the fixing compound situated beneath the notch 8 also sets, thereby operatively joining the notch 8 to the levelling compound 5. The column foot 10' is adapted to the column 1 ' and the column foot 10" is adapted to the column 1 ". The column feet 10 " and 10" comprise plates 11 ' and 11 ' respectively, designed to distribute forces from the column, and pins 12" or cross-irons 12" for guiding and supporting the column 1. On a building site, for example, where the base plate 2 is pre-cast and work must be carried out on the base plate before the column is to be fixed, the open column excavation constitutes a hazard for those carrying out the work, for which reason a cover 13 is used to cover the column excavation 3. A further application of the cover 13 during casting of the base plate, where the cover 13 is fitted at the same time that the mould 4 is assembled, is to prevent concrete or other material being accidentally poured into the column excavation and to prevent the mould 4 extending beyond the concrete plate 2. The cover 13 is therefore larger in extent than the mould 4 and rests on the upper edge of the mould 4. The upper surface of the cover 13 coincides with the upper edge of the base plate 2 and in casting of the base plate 2 forms a space in the base plate 2 above the upper edge of the mould 4, which space during fixing is filled with fixing compound 6. In figure 1 the fixing compound 6 in the space is shown covering the upper edge of the mould 4.

Claims: Claims 1. Method for casting in the fixed bottom end of a column (1) in a fixing position in a column excavation (3) produced by casting of a base plate (2), whilst ensuring that the column assumes a predetermined adjustment level in the column excavation (3), characterised in that in order to produce the column excavation (3) a cage (4) with through-openings, made of metal mesh, for example, and serving as casting mould, is provided, the cage (4) being placed so that it encloses the fixing position and in the casting of the base plate being fixed therein and interlocking therewith, and that in order to produce the predetermined adjustment level a levelling compound (5) is introduced into the column excavation (3) up to the adjustment level, the levelling compound (5) being allowed to set, and that in connection with the casting in of the column (1) its bottom end is placed on the setting levelling compound (5) in the fixing position, following which the column (5) is finally cast in, starting from the support afforded by the levelling compound (5). 2. Method according to claim 1, characterised in that at least one notch (8) is made from the bottom surface (7) of the column (1) upwards in the longitudinal direction of the column and forms a corresponding space for fixing compound (6) thereunder. 3. Method according to either of the preceding claims, characterised in that the column (1) is provided at a distance from its end with a through-opening (9) in the column material. 4. Method according to any of the preceding claims, characterised in that a support for the column end is located on the levelling compound (5). 5. Device for casting in the bottom end of a column (1) in a fixing position in a column excavation (3) produced in a base plate (2) made from a casting compound, comprising means for giving the column (1) a predetermined adjustment level in the column excavation (3) before casting it in, characterised in that the device comprises a cage (4) with through-openings, made of metal mesh, for example, and serving as casting mould for the column excavation (3), the cage (4) being designed, when casting the base plate, to be fixed by the casting compound, and that the said means for defining the adjustment level consist of levelling compound (5) that is introduced into the column excavation (3), so that its upper surface coincides with the adjustment level and is allowed to set before the column (1) is cast in. 6. Device according to claim 5, characterised in that the column (1) at its bottom end has a notch (8), which extends from the bottom surface (7) of the column (1) upwards in the longitudinal direction of the column (5) and forms a space for fixing compound (6). 7. Device according to either of claims 5 or 6, characterised in that the column (1) has a through-opening (9) at a distance from its end. 8. Device according to any of claims 5 to 7, characterised in that on the levelling compound (5) there is a support (10) operatively connected to the bottom end of the column (1). Device according to claim 5, characterised in that the device comprises a cover designed to cover the cage opening at least during casting of the base plate.

Inventors: JOHANSSON WILLY, LAKOMAA ANSSI, JOHANSSON, WILLY, LAKOMAA, ANSSI
Applicants: JOHANSSON WILLY, LAKOMAA ANSSI, JOHANSSON, WILLY, LAKOMAA, ANSSI
Application year: 2000
Main classification: E04C3
IPC codes: E04C3, E04H12