Bridging the tide of false history

Tomorrow is the 43rd anniversary of the opening of the Auckland Harbour Bridge. Misconceptions about its construction abound, writes BRIAN SMITH*.

Over the past few decades we have been subjected to an ever-rising tide of misinformation, false history and erroneous statements. One area where this is applicable is the history of the Auckland Harbour Bridge.

If you take the Bridge Climb at a cost of $125 to $145, you will be given a "historical synopsis" of the construction of the bridge and its widening, illustrated with video excerpts from the documentary broadcast on TV One on January 28.

Much of the information conveyed is wrong and gives a false impression of the concept, design and construction of the bridge. To set the record straight, here, in brief, are the facts.

After the 1946 royal commission report on a Waitemata Harbour crossing, the Ministry of Works in 1949 appointed Freeman Fox and Partners, of London, as consulting engineers for the scheme.

The Auckland Harbour Bridge Authority, constituted by act of Parliament, met first in March 1951 and tenders were invited internationally in January 1952 for a five-lane bridge with two footpaths, of substantially the same appearance as that eventually built.

The lowest tender was from a consortium of two British steel construction companies, Cleveland Bridge and Engineering and Dorman Long (Bridge and Engineering). But financial restrictions imposed by the Government resulted in a redesign, reducing the bridge to four lanes and omitting footpaths.

A contract was let to the British consortium for construction of this reduced-capacity bridge in October 1954 and work on the site began in May 1955.

Because of an acute shortage of skilled men in New Zealand in the early 1950s, the contractor imported a considerable number of workers from Britain. This became an increasing source of friction with the local trade unions and by late 1957 the recruiting of British labour was stopped and only a small number of specialised British tradesmen were retained at the site.

The whole construction period was clogged by labour disputes and strikes, contributing substantially to the many months' delay in completion until the bridge was finally opened to traffic on May 30, 1959.

Right from the start, traffic volumes across the bridge greatly exceeded forecasts, although these had allowed for so-called generated traffic as the North Shore grew. Thus, in March 1964 the bridge authority instructed Freeman Fox and Partners "to report without delay on the engineering feasibility and the material cost of duplicating the present facility on its existing general alignment".

Four months later, Freeman Fox and Partners submitted its report, recommending the widening of the existing structure by the addition of two traffic lanes on each side carried on steel box girders supported by brackets on the existing piers.

Detailed design of these structures followed and tenders for their construction were invited internationally in 1966. The lowest tender was received from Ishikawajima Heavy Industries (IHI), of Tokyo, and the contract was let to it in August of that year. Hence the tag Nippon Clip-on.

The contractor elected to fabricate the box girders in Japan, shipping them to Auckland in large pieces up to 120m long and weighing up to 400 tonnes.

This was a relatively uncommon procedure in those days and it undoubtedly saved much time and money. It also provided much safer working conditions at the site.

Especially for the job, the contractor built and towed to Auckland the two 250-tonne floating cranes, which became a familiar sight on the harbour in 1968.

IHI wisely insisted on providing its own skilled men from Japan to operate those cranes and to handle into place the large girder sections. All the other work on the site was carried out by local sub-contractors. There were practically no industrial disputes during construction.

The original lattice girder bridge and the box girder extensions provide a striking illustration of the almost revolutionary change in the techniques of structural steel design.

Of course, this change did not take place within the 10-year lapse between the two construction periods, but the closeness of these contrasting structures in both time and location is surely unique.

There is a misconception that the box girder is inherently lighter than the equivalent lattice construction, but this is not necessarily so. The original bridge contains about 5800 tonnes of structural steel, compared with nearly 9000 tonnes in the box girder extensions, although the original bridge also contains about 6500 tonnes of concrete in its road deck.

The two men who carried the main responsibility for the design of the bridge and its extensions had interesting backgrounds.

The leader of the design team for the original bridge during the early 1950s was Oleg Kerensky, the son of Alexander Kerensky, the Prime Minister of Russia during the few months preceding the Bolshevik revolution of October 1917.

Oleg Kerensky, with his mother and younger brother, fled Russia for England, their lives in peril, in 1921, when he was 16. He took up engineering and contributed much to that profession, becoming president of the Institution of Structural Engineers in 1970.

The partner responsible for the concept and design of the extensions was Sir Gilbert Roberts who, like Kerensky, was nurtured in the design team for the Sydney Harbour Bridge under the first Sir Ralph Freeman.

Sir Gilbert contributed much to the development of steel welding during and after World War II and he was a pioneer in the development of box structures.

In his early years he was a pilot in the Royal Flying Corps during World War I and a wounded knee left him with a permanent limp, which in no way impeded his brilliant engineering career.

* Brian Smith, of Mairangi Bay, was Freeman Fox and Partners' deputy resident engineer on the first bridge construction and its resident engineer on the extension.