he finest
and consequent danger to the pool and diving stage, excavation and construction would have been much more difficult under tidal conditions and correspondingly more costly.
The technical sub-committee, there- fore, decided in favour of placing the pool parallel to the club building. The diving stage was sited at the western end as it was considered that diving display would generally take place in the latter part of the day and the diver facing east will not be looking into the sun.
Consideration was given to having the diving stage at the side of the pool. This had the disadvantage that divers would be cutting across the pathe of swimmers and there might be serious collisions.
now chosen.
accom.
The orientation as has the advantage that the whole length of the balcony of the building forms a grandstand whilst areas on either side of the pool can modate tiered seats whilst the terrace above the dressing rooms can also' hold spectators. Thus a very large number can be accommodated none of whom would look into the western
sun.
a
To cater for young children separate shallow pool 60 feet x 22 feet and a feet 6 inches deep has been constructed at the eastern end between the main pool and the boundary wall. This pool has incor- ported in it a large fountain. Water withdrawn from the swimming pools and after filtration will be pumped to the fountain over which it will cas cade down at a rate as high as 2 million gallons per day.
This should provide an impressive sight although the function of the fountain is really to aerate the water before it returns to the pools.
The pool is of reinforced concrete construction. Great care has been taken to obtain a watertight concrete so that the pool shall neither leak nor allow saltish water to reach the reinforcing steel bars to corrode them and damage the structure.
To achieve this the sand and stones of suitable gradings were mixed in correct proportions by weight with each bag of cement. These propor- tions were determined by laboratory
tests.
Half way along the pool a line runs down one side wall, across the floor and up the opposite side walls. This line divides the pool into two by a half inch gap. The two halves are joined by a plastic strip known as a water-stop and the gap sealed with rubberised bitumen. The purpose of this joint is to allow the two halves, due to changes in temperatures, to cxpand towards each other without damage and to contract from each other without leaking.
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The walls of the pool have to with. stand pressure on both sides pres- sure from the water in the pool and, when the pool is empty, pressure from the outside soil.
At the deep end the floor is deepen- ed into a pit for high diving. A more usual construction is to have the whole of this end deep. By adopting the pit a more economical construction was obtained. Instead of deep end-wall of 15 feet, the wall is now 7 feet and needs to be one- tenth as strong only. The saving in cost is obvious.
The water for the pool is obtained from the sea. In its raw state it is neither clear nor pure and has to be clarified and sterilised before it is fit for the swimming pool. A further requirement is to maintain the water in this fit state while it is being used by swimmers.
In order to meet these require- ments, modern swimming pools adopt
process known as "Continuous Purification System," requiring a complete purification plant. In the present case, the plant comprises 2 rapid gravity filters, one chlorine dosing apparatus, one aerator foun- tain, sea water intake and pool re- circulation pumping units, associated pipes, valves and meters. Each filter is 200 sq. ft. in area and has 2-ft. depth of graded sand supported on 2-ft. of graded stones.
When water is drawn from the sea, it is made to pass down through the filters. Filtered water is then pumped to the aerator fountain and then dosed with chlorine. In this way the sea water is filtered to remove sus- pended impurities, aerated to restore its natural sparkle, and chlorinated to destroy bacteria, thus rendering it fit to swim in.
The purified water is then deliver- ed to the pool by gravity through a 15 inches pipe leading to 2 distribu- tion ducts formed in the floor and running across the pool, one at the deep end and one at the centre of the pool. Openings fitted with brass orifices are provided at the top of these ducts. Water is withdrawn at the shallow end via a similarly per- forated duct formed in the floor and the water gravitates to the filters through a 12 inches pipe. The water is refiltered to remove turbidities, etc., which it has picked up from swimmers and from dust, etc. in the air. Thus water is continuously cir- culated through the purification plant and returned to the pool.
Water in the children's pool is also recirculated to maintain it in good condition.
A scum trough is provided along the four sides of the pool to carry
LONGITUDINAL SECTION
105