IE43357B1

IE43357B1 - A cylindrical tank

Info

Publication number: IE43357B1
Application number: IE463/76A
Authority: IE
Original assignee: Nolos Ltd
Priority date: 1976-03-05
Filing date: 1976-03-05
Publication date: 1981-02-11
Also published as: ES456514A1; FR2343104A1; ZA771180B; FR2343104B1; GB1545159A; GR62472B; AU506170B2; IE43357L; AU2292777A

Abstract

Improvements introduced into a cylindrical tank having a wall comprising a plurality of vertical prefabricated hollow reinforced concrete beams, the adjacent longitudinal edges of which are joined by cement slurry of which they are joined by cement slurry introduced between them and whose lower ends are supported on a reinforced concrete foundation, and a concrete floor cast into the wall, characterized in that the tank comprises at least one post-tensioned strap that ties the beams around the outer periphery of the wall.

Description

This invention relates to cylindrical water tanks, silos and i.he like large container;!, hereinafter referred to collectively as cylindrical tanks. The object of the invention ls to provide a construction of cylindrical tanks which may be conveniently and quickly constructed with low erection costs.

Accordingly the present invention provides a cylindrical tank having a wall which comprises a plurality of upright precast tubular reinforced concrete beams which are jointed together and whose bottom ends are supported upon a reinforced concrete foundation, and a concrete floor oast within the wall, the tank further comprising at least one post-tensioned high tensile strap binding the wall around the exterior periphery thereof, and wherein major portiona of adjacent longitudinal edges of adjacent beams define a recess in which cement grouting is inserted, fhe remaining portions of the adjacent longitudinal edges of adjacent beams defining opposed arrises adjacent to but spaced from the exterior surface of the wall, whereby the strap is spaced apart from the exterior surface of the wall in the region of each joint the adjacent edges of the beams being sufficiently close together at the opposed arrises that grouting does not substantially pass between the opposed arrises when inserted in the recess. 433S7 The invention will be understood from the following description of an embodiment thereof given by way of example only with reference to the accompanying drawings, in which: Fig. 1 is a diagrammatic vertical section through a cylindrical tank; Fig. 2 is a diagrammatic horizontal section through the joint between two of the hollow beams forming the wall of the tank; Fig. 3 is a more detailed horizontal section through a portion of the wall of the tank; and Fig. 4 is a horizontal section through a joint between two hollow beams having an alternative configuration to those shown in figures 1 to 3.

Referring to the drawings the cylindrical tank includes a wall comprising a plurality of upright precast hollow reinforced concrete beams 10 disposed edge to edge. Each beam 10 is of uniform cross-sectional shape, being approximately rectangular, the longitudinal edges 11 each being inclined inwardly from a grooved area 12 for a portion of the depth of the beam 10 and then inclined outwardly for a major portion of the depth of the beam 10 to form a recess 14 between adjacent beams. The adjacent longitudinal abutting edges of the beams 10 are jointed by inserting a cement grouting 15 in the recess 14 between the two beams.

The remaining portions of the adjacent longitudinal edges of the adjacent beams defining opposed arrises 13 which are adjacent to but spaced from the exterior surface of the wall in the region of each joint. The portions of the beams forming the opposed arrises 13 are sufficiently close together that the grouting 15 does not substantially pass between the opposed arrises 13 when inserted in the recess 14.

The beams 10 are erected in upright position on a reinforced concrete foundation 17 and held between an exterior concrete base 18 and a concrete floor 19 of the tank cast within the wall formed by the beams 10. The beams are each keyed or tied into the ..uoor 19 by a suitably shaped mild steel bar 20. The joints between the floor 19 and the upright beams 10 are filled with a waterproof polysulphide sealing compound 21 covered over by a protecting layer of concrete 22. Around the exterior, adjacent the bottoms of the beams 10, the wall is bound by two high tensile steel wire straps 23 which are post-tensioned and covered in a concrete casing 24 formed against the exterior of the wall, the interface of the casing 24 and the wall being protected by a layer of polysulphide compound 28 to prevent ingress of moisture to the straps 23 and resultant corrosion thereof.

Further high-tensile wire straps 23 are provided midway up and at the tops of the hollow beams 10 to bind the said beams 10 together to form the wall of the cylindrical tank. The wire straps 23 are protected as before by concrete casings 24 and where necessary polysulphide sealing compound 28. The tops of the beams 10 are locked together by a concrete capping member 29 which houses for strength a mild steel bar 30. The capping member 29 effectively holds the tank together in the event that one or more of the wire straps 23 should fail.

Each beam 10 is cast with a preformed polystyrene core 16, the said core 16 enhancing the heat insulation properties of the beam. Each recess 14 is provided, adjacent the grooved areas 12, with a polysulphide sealing compound 25 which is protected by a concrete plaster 26 which fills the grooved areas 12. The grouting 15 fills the recess 14 but does not substantially pass between opposed arrises 13 of the abutting beams 10. It is possible to protect the wire straps 23 by providing in protective concrete coverings 27 which are cast simultaneously with the concrete, casings 24. Thus the straps are completely surrounded in the region of each wall joint thereby giving protection against water seepage at the joint. In this manner it is possible to increase the effective life of the wire straps 23 which bind the beams 10 together. Subsequently each joint may be pointed with further grouting material 15.

Figure 4 illustrates a different configuration of beams to that shown in figures 1 to 3. However, the same general features are present and are indicated by the same reference numerals. The wire straps are not shown but are protected as described previously.

The basic difference in the beams of figure 4 is the shape of the recess 14 and the opposed arrises 13.

A second embodiment of the invention envisages the use of a plurality of high-tensile steel straps with protective plastics coatings and post-tensioned for binding the beams together to form the wall of the tank.

In this instance the said straps are positioned closer together towards the tank base, where pressure is greater. The spacing of and the number of straps used is varied relative to the height and diameter of the tank.

In both embodiments described the concrete beams are preferably 200 mm. in depth, 500 mm. wide and have a core wall thickness of 37 mm. An advantage of the constructions described is that when water is fed into the tank the temperature of the wall units will drop resulting in a contraction of the overall diameter. The joints between the beams are thus compressed, leading to a tighter seal between the beams. The invention is not limited to the embodiments described above which may be modified or varied without departing from the scope of the invention.

Claims

1. CLAIMSi1. A cylindrical tank having a wall which comprises a plurality of upright precast tubular reinforced concrete beams which are jointed together and whose bottom ends are supported upon a reinforced concrete foundation, and a concrete floor cast within the wall, the tank further comprising at least one post-tensioned high tensile strap binding the wall around the exterior periphery thereof, and wherein major portions of adjacent longitudinal edges of adjacent beams define a recess in which cement grouting is inserted, the remaining portions of the adjacent longitudinal edges of the adjacent beams defining opposed arrises adjacent to but spaced from the exterior surface of the wall, whereby the strap is spaced apart from the exterior surface of the wall in the region of each joint, the adjacent edges of the beams being sufficiently close together at the opposed arrises that grouting does not substantially pass between the opposed arrises when inserted in the recess.

2. A cylindrical tank as claimed in claim 1, wherein the tops of the beams are locked together by a reinforced concrete capping member.

3. A tank as claimed in claim 1 or claim 2 wherein the strap is protected by a covering of plastics material.

4. A tank as claimed in claim 1 or claim 2 wherein the strap is covered by a concrete casing formed against the exterior of the wall.

5. A tank as claimed in claim 4, wherein a waterproof sealing compound protects the interface between the concrete casing and the wall.

6. A tank as claimed in any preceding claim, wherein each beam has a core of heat insulating material.

7. A tank substantially as described with reference to Figures 1 to 3 or to Figure 4 of the accompanying drawings.