January_1971 — Page 18

Low block

Placing roof beams

Low block with all precast beams erected

Roof beams in position with third floor beams below

Casting tie beam

=

Fig. 1. Framing plan for low block

14

+1

PLACED

H-C

UNDERROHUP

be 2ft. lower than would otherwise have been needed.

Structural framing

Several framing proposals were in- vestigated, the final form being adopt- ed after a careful study of the method of construction involved.

Since a prestressed, precast system was to be employed, it was necessary to frame the structure in such a way that the prestressed portal frame would not need to resist horizontal loads; otherwise the effect of rever- sible bending moments would make the prestressed concrete structure un- economical. Structural cores were therefore used to resist horizontal loads on the building, with the floors acting as diaphragms. The cores are also used as service cores for lifts, stair- cases and air-conditioning rooms.

In the low block, Fig. 1, the services core is at the back, accommodating the staircase, washrooms and lavatories.

Far East BUILDER, January 1971