lic jack is to be applied at each junc- tion of the longitudinal and the trans- verse stiffeners, and the deflection and strains at various positions measured. The influence surfaces for deflections and moments derived therefrom will be compared with those obtained from the perspex model.
(2) Service load tests:
The model is subjected to the same loading conditions as adopted in the design, i.e. HA type M.O.T. loading on (a) concave lane only; (b) convex lane only; (c) both lanes. The uni- formly distributed load (U.D.L.) will be provided by 6 in. concrete cubes, and two moving point loads, provid- ed by hydraulic jacks, will represent the knife edge load (K.E.L.). Deflec- tions and strains will be measured which serve as a direct check on the design.
(3) Destructive test:
The model will be loaded simul- taneously with eight equal uniformly spaced point loads to represent the U.D.L. and two independent point loads at mid-span to represent the K.E.L. The loads will be increased proportionately until the model fails. During the test the cracking load will be ascertained together with the be- haviour of the prototype under vari- ous degrees of overload. The mode of failure and the collapse load of the
model will provide an indication of the load factor of the prototype.
Conclusion
Model investigations, such as the one described above, are a cheap and accurate method of checking unusual designs incorporating previously un- proven features. A structural model enables the designer to determine the behaviour of the prototype without making any simplyfying assumptions regarding the state of stress in the
structure.
Acknowledgements
The model investigation is being carried out in the laboratories of the Civil Engineering, Department of
The au- University of Hong Kong.
thank Professor S. thors wish to Mackey for his permission to use the laboratory facilities and for his en- couragement during the investigation.
The flyover is designed by the Ar- chitectural Office in liaison with the Roads and Drainage Division (H.K.) of the Civil Engineering Office of the Public Works Department, Hong Kong. The latter Division will also be responsible for construction of the flyover as part of the overall Water- front Road Scheme.
The authors gratefully acknowledge the co-operation of the P.W.D. which commissioned this investigation.
Holing through of 22-mile long tunnel
A 21⁄2-mile long tunnel, part of a HK$7 million water sup- ply link system from Tai Lam Chung Reservoir to Lam Tei in Castle Peak, New Territories, HK, was blasted through last month.
The whole length of the trunk feed from Tai Lam Chung to Lam Tei is nearly 41⁄2 miles. It is part of a huge project by the PWD to ensure an adequate supply of water to meet the ex- pansion of Yuen Long as well as developments at Castle Peak. The 21⁄2-mile tunnel, stretching from So Kwun Wat to Lam Tei, is the longest of three tunnels in the link.
new
The tunnels are horse-shoe shaped in cross section and mea- sure 7 ft. 6 in. from the arch to the flat floor. They are joined by 48 in. diameter steel pipes which will soon be laid across the valleys of So Kwun Wat and Sui Lam. This new link will al- so be supplying raw water to the proposed multi-million dol- lar water treatment works near San Hui.
HILLALDAM
SLIDING DOOR GEAR
JONES X 22 CRANE
FOR EVERY DOOR THAT SLIDES
ALL TYPES OF GEAR ARE READILY AVAILABLE IN THE FAR EAST
FOR FURTHER DETAILS PLEASE CONSULT:
HONG KONG: DEACON & CO. LTD. Agents and Stockists, Hong Kong Bank Building, Hong Kong. Tel: 236111 SINGAPORE: A. CLOUET & CO. LTD. Agents and Stockists, P.O. Box 1922, 33 Wallich Street, Singapore 2. Tel: 75535-36-37 MALAYSIA: A. CLOUET & CO. LTD, Agents and Stockists, P.O. Box 963, 206 Loke Yew Bldg., Kuala Lumpur. Tel: 87327-86865
1
THAILAND: LOXLEY (BANGKOK) LTD. Agents and Stockists, P.O. Box 214, Loxley Building,
304 Suapah Rd., Bangkok. Tel: 26641-7
PHILIPPINES: AMON TRADING CORPORATION. Stockists, P.O. Box 1151, 246 Buendia Avenue, Makati, Rizal, Manila. Tel: 88-09-61
50
Far East BUILDER, May 1968.
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