maximum allowed by the building re- gulations. It has a total height of 298ft. 6in. above ground level and consists of a five-storey podium oc- cupying the full site area with the tower block above set back on plan dimensions of 201 ft. by 136 ft.
Structure
The superstructure is of in-situ re- inforced concrete construction incor- porating flat plate floor slabs. Maxi- mum column size is 48in. x 36in. at ground floor, reducing progressively to 24 in. x 24 in. Upper floor slab thicknesses are generally 9in. and 10 in.
The adoption of flat plate con- struction allows maximum flexibility for internal planning of the offices.
The structural concrete was de- signed in accordance with British Standard Code of Practice C.P. 114 (1957) for the The Structural Use of Reinforced Concrete in Buildings, in- cluding the adoption of load factor design and increased concrete stresses having regard to age factor.
Except in columns in the lower half of the building, the structural con- crete mix was 1:12:3, for which a minimum 28 day cube strength_of 3,750 lb./sq. in. was required. columns in the lower half of the
building a 1:1:2 mix was specified with minimum 28 day strength of 4,500 lb./sq. in. (Wind loads, cal- culated in accordance with the Hong Kong Building (Construction) Re- gulations, are taken on the central core walls).
The total volume of structural con- crete is in the order of 48,500 cu. yd. and the total weight of high ten- sile and mild steel reinforcement is approximately 4,000 tons.
Ground Work
All the major problems associated with the construction of the building were met with during the early stages of the work.
The site is on land reclaimed from the harbour at the turn of the cen- tury, and site investigation boreholes revealed that, beneath a surface layer of made up ground up to 28 ft. thick, there is a stratum principally com- posed of silts, sands and some clay, the main underlying stratum being decomposed granite.
The surface of this decomposed granite was encountered at depths from 39 ft. to 55 ft. below ground level.
The surface of solid granite was encountered at depths varying from 79 ft. to 110 ft., and standing
water level was at a depth of F1 ft. 3in.
These ground conditions indicated the necessity for providing piled foundations, and the building is sup- ported on 1,370 piles of the driven Cast in-situ Colcrete type, each pile being 20in. diameter with a safe load carrying capacity of 105 tons singly and 89 tons per pile in groups.
Prior to commencement of excava- tion for the single storey basement, which extends over the whole site area, steel sheet piling in 40 ft. lengths of Larssen No. 3 section was driven around the perimeter of the site, following which excavation was carried out down to a depth of 7 ft. below existing ground level in the centre of the site and to a further 3 ft. depth immediately within the sheet piled perimeter.
The walings to the perimeter piling were strutted back to the raised mound thus formed in the centre of the site.
After withdrawal of some 4,800 existing timber piles in lengths very- ing from 12 ft. to 50 ft., foundation piling was carried out from the ex- cavated levels to depths of up to 73 ft.
An old rubble mound ran under the site, parallel with Ice House
**
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Mandarin
Lat
House style. Prince's Building (Palmer & Turner, architects) and Mandarin Hotel (Leigh & Orange), both built Hong Kong Land Investment & Agency Co., Ltd.
for
50
Far East Architect & Builder August, 1965