BRIDGE MAKING

Wairarapa Times-Age, 4 February 1939, Page 4

BRIDGE MAKING

NEW CONSTRUCTION METHOD

NEW ZEALANDERS’ IDEA. ADOPTION BY WAR OFFICE. A new system of building bridges, the patent of two New Zealanders, Captain A. M. Hamilton, of Christchurch, and Mr G. D. White-Parsons, of Lyttelton, has been adopted by the British War Office and the Ministry of Transport.

Briefly, it is building on the “meccano” principle. Instead of bridges being separately designed the New Zealanders’ idea is that all parts are standardised and that these parts arc then assembled into bridges of any length required. In this way bridges may be virtually “mass produced” and the parts kept in stock ready for immediate use.

Hitherto there has been no such system, and its importance may be gauged by the fact that the Science Museum in South Kensington, London, where all the great advances in the history of science are recorded, lately acquired a complete set of models of these bridges as being a most noteworthy development in the art of bridge building. INVALUABLE SYSTEM. The chief feature is the greatly increased speed of erecting bridges, or repairing damaged ones. For all purposes, such as temporary roads, replacing bridges damaged by wash-outs, for military purposes or as a safeguard against damage to bridges in air raids, the system is considered by the authorities to be invaluable.

Before bolting up the fabricated steel girders are not unlike meccano parts. The principle was first established by Captain Hamilton in the course of constructing the Rowanduz Road through Kurdistan. In Persia the Anglo-Iranian Oil Company now has many bridges built on this system in use for the development of its oilfields.

The British War Office has been carrying out severe field tests on these bridges for the past four years, and it has lately been adopted as the standard heavy-duty type—that is, for transporting the heaviest artillery, tanks and lorries used by the modern army. The remarkable success of the tests to which the bridge was subjected simulating the' “worst possible conditions of field use”—proved highly gratifying, not to the inventors but also to the officials of the Roya'. Engineers conducting tim trials. The method of assembling and “launching” these bridges will now be taught at the School of Military Engineering, cnatham, and to Royal Engineer Units generally.

REPLACEMENT IN WARTIME.

For air raid precautions the Institution of Civil Engineers now has the matter of the general use of the bridge in England under review in conjunction with the Ministry of Transport. Lhe well-known journal Engineering has given the unit-construction bridge its repeated blessing and approval foi the urgent bridging problems all transport and departmental engineers today have to face—especially in view of the present international situation. To give an indication of the value of this new bridging system during wartime, it is claimed that should, say, Waterloo Bridge, or any other chief bridge of London, be destroyed by bombs, a temporary structure tc carry the same heavy traffic, could be built in most cases within a fortnight if all the necessary measures, such as ample stocks of parts, and the erection gear, were in readiness for suet a crisis. '

Aeroplane hangars can also be erected from standard parts on the same oolted principle, and the British Air Ministry already has a number oi hangars constructed to this particular application of the New Zealanders’ invention.

Both in the case of the bridges ano the hangars the inventors have been closely associated with Callender’s Cable and Construction Company, Limited, which is the joint patentee ol these structures, though best known in New Zealand lor their electric cables.

The system has already been brought to the attention of the New Zealand Public Works Department, and there is a possibility that two well-known Wellington firms of structural engineers may soon be fabricating these bridges and hangars for the Dominion, within the country itself.