MALAYSIA AND SINGAPORE
Prestressed floodlighting tower for the Merdeka Stadium, Kuala Lumpur
SOUND, SLOW PROGRESS IN PRESTRESSING
by Rex Shelley, BA, BSc, AIMunE, AMICE, AMIE(S) Design Engineer, Hume Industries (Far East) Ltd.
PRESTRESSED
concrete has been used fairly extensively in Singa- pore and Malaysia, but the low costs. of cast-in-situ reinforced concrete ob- tainable in the region have limited its economical range.
First landmark in the development of prestressed concrete was the Mer- deka Bridge. Singapore. This struc- which is Singapore's longest bridge, was constructed in 1955/1956
ture,
by Paul Y. Construction, the main contractor, and with Hume Industries (F.E.) Ltd. carrying out prestressed concrete work. The bridge consisted of 366 beams, each 80 ft. long. Beams were cast on site. and Lee-McCall bars were used for both beam and transverse slab stressing.
Prestressed concrete was selected for this bridge because of the lower deadweight of P.S.C. compared to R.C. This advantage also made P.S.C. the choice for two projects oc- curring at about same time. The first was the 106 ft. floodlighting towers for Kuala Lumpur Merdeka Stadium in 1957. These towers were design- ed, tensioned and erected by the Pub- lic Works Department, Federation of Malaya, using Hume spun concrete pipe sections with ducts cast in them. The second was the use of Raymond piles 110 ft. long, 24" and 34" O.D., cast in Singapore and moved by barge up to the East Coast of Malaysia for five bridges constructed by C.I.T.R.A.
Prestressed concrete became econo- mical for shorter span road bridges up to 40 ft. initially and now up to 55 ft., when prestressing beds were set up in factories and when the economies of mass production, the simplicity of bridge construction with precast beams and the advantages of quality control at the factory, swung the balance in favour of prestressed
concrete.
First Hume Industries in 1953 and later Gammon Malaya set up pre- stressing beds and cast beams using standard sections developed by the Prestressed Concrete Design Group of the United Kingdom. A great many bridges have been built in the region with these pretensioned beams.
One of the reasons for the rapid growth of demand for prestressed concrete bridge beams was that many bridges were being constructed in re- mote areas where skilled labour was scarce and supervision was difficult. An interesting and unusual applica- tion of P.S.C. in Kedah in 1956 arose out of similar circumstances.
The Second Engineer's Squadron of the British Army designed and erect- ed two bridges using short precast sections, cast by Hume Industries, and post tensioned the bridge units on the abutements on a timber scaffold.
The
Far East Architect & Builder February, 1967
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