US3403492A

US3403492A - Construction of concrete liquid reservoirs such as swimming pools

Info

Publication number: US3403492A
Application number: US528703A
Authority: US
Inventors: Spencer Francis Dudley
Original assignee: Spencer Francis Dudley
Current assignee: FRANCIS DUDLEY SPENCER
Priority date: 1965-02-24
Filing date: 1966-02-21
Publication date: 1968-10-01
Anticipated expiration: 1985-10-01

Description

F. D. SPENCER SUCH AS SWIMMING POOLS .'5 Sheets-Sheet 1 Oct. l, 1968 CONSTRUCTION OF' CONCRETE LIQUID RESERVOIRS Filed Feb. 2ll 1966 F. D. SPENCER UCTION 0F CONCRETE LIQUID RESERVOIRS Oct. 1, 1968 CONSTR Filed Feb. 2l, 1966 SUCH AS SWIMMING FOOLS 5 Sheets-Sheet 2 FIG.3

Oct. l, 1968 F. D4 SPENCER CONSTRUCTION OF' CONCRETE LIQUID RESERVOIRS SUCH AS SWIMMING FOOLS 5 Sheets-Sheet 5 Filed Feb. 2l, 1966 FIG 1.... ..3 .w........o..6...o.

United States Patent O Mice 3,403,492 CONSTRUCTION OF CONCRETE LIQUID RESER- VOIRS SUCH AS SWIMMING POOLS Francis Dudley Spencer, 51 Nelson Road, Killara, New South Wales, Australia Filed Feb. 21, 1966, Ser. No. 528,703 Claims priority, application Australia, Feb. 24, 1965,

f 55,584/ 65 3 Claims. (Cl. 52-744) ABSTRACT OF THE DISCLOSURE A method of constructing a concrete liquid reservoir comprising the steps of laying reinforcing tendons in the floor between opposite sides of the reservoir. End portions of the tendons are passed through bent anchored guides bending them into the wall alignment. Intermediate portions of tendons which extend between a pair of guides are prepared to provide for slip between the portions and the concrete oor. The concrete is then poured to cover the intermediate portions of the tendons and the guide. The tendons are prestressed and the ends are supported while in tensioned condition to insert stress to the oor. Then the concrete is poured to form the walls around the end portions of the tendons. The concrete is cured and the support for the ends of the tendons is removed thereby transferring the stress in the tendons to the concrete walls in addition to the oor of the reservoir.

This invention relates to the construction of concrete liquid reservoirs and more particular to swimming pools.

The present method of construction of such units involves the use of large amounts of reinforcing steel rods and concrete aggregate.

It is the main object of this invention to produce a swimming pool or other liquid reservoir, the main body of which is formed from concrete, which is considerably cheaper to produce than hitherto.

It is a furtherobject of the invention that the economy in construction be achieved through the application of the pre-stressing and post-tensioning techniques to the present form of structural units.

To this end the invention provides a method of constructing a concrete reservoir for liquids which has a oor and surrounding walls, comprising the steps of laying reinforcing tendons or rods in the floor between at least a pair of opposite sides of the reservoir, passing end portions of the tendons through bent anchored guides so that they are bent into the wall alignment, preparing intermediate portions of the tendons which extend between a pair of guides to provide for slip between said portions and the subsequent concrete floor, pouring the concrete of the oor to cover the intermediate portions of the tendons and the guides, placing the tendons under tension, supporting the ends of the tendons while in a tensioned condition so as to impart stress to the floor, pouring the concrete to form the walls around the end portions of the tendons and allowing the concrete to cure and removing the support for the ends of the tendons so that the stress in the tendons is transferred to the concrete walls in addition to the oor of the reservoir.

The invention also provides a swimming pool or other liquid reservoir constructed according to the above method.

A preferred embodiment of the invention will now be described in which the constructional method is applied with respect to a swimming pool. Reservoirs of this kind may be of varied shape but in a conventional sense they are substantially rectangular in plan with the four upright 3,403,492 Patented Oct. 1, k1968 adjoining walls joined to the rim of a Hoor tapering towards one end.

The properties of a strength and light-weight construction are well known for pre-stressed or post-tensioned concrete slabs. However, due to several diiculties in adapting for this purpose, pre-stressed and/or post-tensioned slab have not been employed to the present time in the construction of swimming pools.

A preferred method of construction of the pool is illustrated in the accompanying drawings, in which:

FIG. 1 is a fragmentary plan view of one end of the pool showing the disposition of tendons within a ducting;

FIG. 2 is an elevation in longitudinal section of the part of the pool shown in FIG. l;

FIG. 3 is an enlarged view of the pool wall in vertical section;

FIG. 4 is a fragmentary perspective of the pool floor showing the tendons in place; f

FIG. 5 is a similar view showing the concrete blockwall constructed and the tendons secured in stress to beams across the top of the Wall;

FIG. 6 is a similar view showing a further concrete wall poured within the cavity between the concrete block walls; and

FIG. 7 is a similar view showing the tendons cut off ilush with the top of the concrete wall.

The preferred method of construction of the pool is as follows. A suitable bed of compacted sand 8 for the floor 10 of the pool is firstly formed, over which is laid a layer of moisture-proof sheeting 9. Metal tubes or ducts 11 are positioned in parallel intersecting rows both laterally and longitudinally at the medial or neutral plane of the pool floor 10. Tendons or rods 12, which may be single or multi strand, of high tensile steel are then laid in the parallel lines of ducts 11 extending across the width of the pool and longitudinally from end to end forming the matrix over which the concrete floor 10 will subsequently be poured.

Guide sleeves 13 for individual tendons 12 comprise an arcuate tube, four of which are flared 4outwardly from the end of each duct 11. All of these sleeves 13 are laid fat spaced intervals around the rim 14 of the pool floor 10 so that with pouring of the concrete for the floor 10 they become embedded therein. Three stirrup rods 13A are located as stays for each of the guides 13 (see FIG. 3). The tendons 12 have their ends passed through respective guides 13 located at opposite sides of the pool and are bent thereby through approximately so that the opposite end portions of each tendon extend in the neutral axis of the wall alignment for .the Pool.

A lubricant may be coated over the intermediate portions of all the tendons 12 which lie within the `respective guides 13 and ducts 11 in the floor 10 of the pool. It is possible to omit the duets 11 and to provide for sfuicient slip for the tendons Within the subsequent concrete casing simply by the adjunct of lubricant. The next step in the method is to pour 'the concrete for the floor 10 so that it covers both the ducts 11 carrying the tendons as well as all of the guide sleeves 13. This concrete is allowed to cure.

The wall construction is then commenced by the formation of a cavity blockwall 15, for example, of concrete blocks. The end portion of the tendons 12 extend upwardly through the cavity 16 rand beyond the end of the blockwall.

By expedient means each end of each tendon 12 passes through a metal beam 17 which straddles the cavity 16 of the blockwall 15 and one end is secured fast to its respective beam 17 while by suitable jacks 18 and clamps 19 the other end of each 4tendon 12 is drawn taut and tensioned and locked in this position. It will be appreciated that the tendons 12 vare free to move within the ducts 11 and guides 13 in the concrete floor through which they pass and the tensioning applied exerts considerable stress upon the blockwalls 15 and through these walls to the floor of the pool to effect post-tensioning thereof.

Concrete is then poured into the cavity 16 of the blockw-alls -to a level below Ithe upper end 21 of the blockwalls. After curing of the concrete 20 the structure is locked olf by a simple severing of each end of each tendon 12 iat 22 below its supporting beam. Immediately the stress previously exerted upon the blockwalls 15 is transferred through the adhesion of the concrete Wall 20 to the end portions of the tendons 12 to the concrete wall 20 while being maintained across the floor 10 of the pool. lPre-stressing of the concrete walls 20 is thus provided for.

The above described method may be varied in several ways while retaining the novel basic conception of the invention. In place of the blockwalls 15 some other form of support may be provided to retain the tensioned condition of the tendons during pouring of the concrete walls. Removable plates may serve this purpose, as well as functioning as formwork for the concrete walls. Locking-off may be achieved in one of many ways but preferably this is done by cutting the individual tendons by an Oxy-acetylene torch.

Whereas the invention has now been described with reference to a preferred embodiment it is to be understood that .modioation thereto is feasible within its scope.

What I claim is:

1. A method of constructing a swimming pool having a floor and peripheral surrounding walls, comprising the steps of forming the oor by preparing a bed for .the door, spreading moisture-proof sheeting over the bed, laying one set of steel tendons in substantially parallel lines across one dimension `of the -pool door and another set of steel tendons in substantially parallel lines across another dimension of the pool floor and substantially normal to the said first set, positioning a -plurality of guide sleeves around the rim of the intended oor for the pool through each of which an individual end portion of a tendon is passed, said sleeves being anchored with respect to the oor and being bent it-o direct the end portions of the tendons upwardly into the wall alignment rendering the portion of each tendon intermediate its end portions slidable with respect to the subsequent `concrete door, pouring the concrete of the floor to cover the intermediate portions of the tendons and the guide sleeves, permit-ting the poured concrete to cure, constructing substantially upright cavity blockwalls around the perimeter of the pool floor, fastening one end of each tendon to an upper part of a respective blockw-all, applying strain to the other end of each tendon to impart stress to the concrete floor and fastening said last-mentioned end to an upper part of its respective blockwall while the tendon is under strain, pouring the concrete to form the Walls into the cavity of the blockwalls and around the end portions of the tendons, permitting the concrete of the walls to cure, and cutting of the ends of Ithe tendons below their fastening points so that the stress in the tendons is transferred to the concrete walls while maintaining the stress on the concrete floor.

v2. A method according to claim 1, wherein a lubricant is applied to said intermediate portion of the ltendons before the concrete iioor is poured to provide freedom for slip between the tendons and the concrete Hoor.

3. A method of constructing a concrete reservoir for liquids having a floor and peripheral surrounding walls, comprising the steps of forming the oor by preparing a bed for the Hoor, spreading moisture-proof sheeting over the bed, laying one set of steel tendons in substantially parallel lines across one dimension of the reservoir floor and another set of steel tendons in substantially parallel lines across another dimension of the reservoir oor and substantially normal to the said first set, positioning a plurality of guide sleeves :around the rim of the intended floor for the reservoir through each of which an individual end portion of a tendon is passed, said sleeves being anchored with respect to the oor and being bent to direct lthe end portions of the Itendons upwardly into the wall alignment rendering the portion of each tendon intermediate ,its end portions slidable with respect to the subsequent concrete door, pouring :the concrete of the oor to cover the intermediate portions of the tendons and the guide sleeves, permitting the poured concrete to cure, constructing substantially upright cavity blockwalls around the perimeter of the pool oor, straining said tendons and fastening ends of said tendons to upper parts of respective blockwalls, pouring the concrete to form the walls into the cavity of the blockwalls and around the end portions of the tendons, permitting the concrete of the Walls to cure, and cutting off the ends of the tendons below their fastening points so that the stress in the tendons is transferred to the concrete walls While maintairb ing the stress on the concrete floor.

References Cited UNITED STATES PATENTS 2,250,763 7/ 1941 Hild 52--426 XR 2,655,846 10/ 1953 Freyssinet 52-230 XR 2,902,157 9/ 1959 Culver 52-223 XR 3,060,640 10/ 1962 Harris 52-230 OTHER REFERENCES The Preload System, page 28, dated Nov. 23, 1942, by The Preload System C0., 1730 Grand Central Terminal Building, New York.

HENRY C. SUTHERLAND, Primary Examiner.

P. C. FAW, Assistant Examiner.