SS-A
BELG
Stair flights precast on site
Internal wall units placed and jointed at third floor level
quicker and the sections are strong enough to be lifted by travelling crane and moved to the adjacent storage area within hours.
The time needed for vertical stack- ing is also reduced in Hong Kong one day as compared with a mini- mum of three days in Japan.
In the stacking area the sections are numbered and when required by the erecting teams they are moved by tower crane and placed in position in the building where they are clamped down by tubular steel supports until they are secured by welding the rein- forcing bars and injecting cement
mortar.
The joints are subsequently sealed by concrete and caulked.
Central Factory
In Japan, the Taisei Construction Co., Ltd. has a central casting yard in Chiba Province and transports units by road to a number of build- ing projects.
The panels are cast in horizontal
Jointing completed on ground floor balcony. Scaffolding is for final finishing work
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steel moulds on wheels and for fac- ing units the window frame is an- chored in position. A layer of facade concrete about 11⁄2 in. thick is pour- ed in from a travelling skip, followed by vibration and levelling. Pre- prepared steel reinforcement mats, in- cluding hooks for hoisting, are either already in position on wood spacers or are now laid in and fixed to wood blocking pieces around the window.
Another layer of concrete is pour- ed to the required thickness, to the top of the edges of the mould and the whole is then vibrated both by poker vibrators and externally by vibrating machines riding on the edges. The surface is then trowelled and brushed.
The whole mould is then wheeled forward into a steam curing chamber, closed and immersed in steam to a temperature of about 80 degrees C. for about four hours.
The edge shuttering is removed simultaneously by unbolting and clearing with a hammer. An over- head crane hoists the slab and places it vertically in a tubular steel stack to await transportation.
An alternative to the brushed finish is a shot-blasted finish, achieved by bombarding the surface with steel pellets.
Hong Kong Progress
In Hong Kong, the Fuk Loi block. has now reached third floor level. Progress has been slower than anti- cipated, due in some measure to the appalling weather experienced in the Colony over the past few months.
However it is noticeable that the work cycle is faster with each suc- ceeding floor, as the site staff becomes better trained.
It would appear impossible in Hong Kong to complete any building without it being surrounded at some stage by bamboo scaffolding and this is an incongruous aspect of the site. But it must be remembered that this is an experimental scheme and that the panels were designed to produce a building almost identical to one al- ready built.
For this reason there are far more variations of mould than would nor- mally be the case. Windows are not cast-in and no provision is made in the panels for plumbing or conduits. The scaffolding is therefore provided for the finishing trades and for the application of a final cement spray finish.
While the scheme is only at the mid-way stage, certain advantages to this method of working are already apparent. The first of these is the rationalisation of site work. Labour is fully utilised and there is no inter- ference of one trade with another. Steel benders for instance work in an area of their own. The reinforce- ment mats are pre-assembled and checking is made easy.
There is also a better control of concrete production and panels of a consistently high quality, finish and strength are being manufactured.
Far East Architect & Builder August, 1966