groups of like-sized units as they emerge from their respective batteries, rather than gradually from one end of the block to the other.
A battery producing say 12 units will take some 3 hours to strike and reassemble. Fixing of stop ends and other preparatory work will occupy subsequent short periods, after which the battery would again be ready for concreting, not later than the day following striking. With a weekly cycle, this will allow six days curing time.
This method gives the maximum undisturbed curing time in the cast- ing position, assisted by a natural
build-up of heat within the battery. without the need of artificial accelera- tion. Only one movement of each unit is required, direct from mould to position in the building; thus the risk of damage and the need for special handling reinforcement are both greatly reduced. The same pro- cedure will be adopted for floors as for walls, except that, between re- moval from the battery and building
be in, they will turned to the horizontal by means of swivelling suspension chains.
Improvement
Some improvements on the original plant have been made since this pro- ject was completed.
Battery master units are now sup- ported by steel channels cast into them: steel cantilever brackets at each end of master and intermediate units support rails above the battery, on which a casting gantry runs (Fig. 9).
This gantry, operated by one man, carries equipment for casting and vibrating the concrete, including a hopper and "trousers" fitting to de- liver concrete to adjacent moulds together, and pairs of vibrators on counterbalanced reels to make the operation of moving them less ardous.
The gantry is transferred bodily from section to section by the tower crane. Demoulding is done by block and tackle from simple beams placed
Fig. 7. Multi-storey block at Edmonton, UK
on the rails (Fig. 10), and the separat- ed panels are lifted by the crane to their place in the building. Special attention is paid to safety in the erec- tion operations, and a simple guard rail is fitted around the working area by sockets placed in the outside slabs.
Structural joints are made by an in-situ filling of concrete, and detail- ing departs from norma! procedure only in permitting cladding joints and internal floor panel joints to occur away from three-way intersections.
In this way, design and production are not tied to a room-sized unit, but joint masking now becomes a pro- blem. With the floor slabs, an attempt is made to conceal the joint by relying
on a very small slab thickness toler- ance of 16 in. and covering the junction with a paper strip applied to the ceiling. This concealment is generally successful, which is a tribute to the accuracy of the casting.
Sometimes a plus tolerance meets a minus, and then the ceiling is finished flush. This means that the floor finish has to hide the discrepancy. Since screeds are eliminated, this becomes a test of the finish itself, and it remains to be seen whether the bonded felt- pvc sheet used here is capable of this rather severe task.
The cladding is by concrete panels in the form of an inverted T with joints on the centre line of windows. On the long facades, the panels are
Fig. 8. Erection of wall panels on ground floor, cladding slab Fig. 9. Casting gantry running on rails above a battery
moulds at back and batteries on left.
Far East Architect & Builder August, 1966
47
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