MacArthur Planned To Destroy Sydney Harbor Bridge in WWII

In 1942 during WWII, General Douglas MacArthur ordered secret plans to be drawn up to destroy Sydney Harbor Bridge if the Japanese invaded Australia.

Explosives were to be planted on the northern approach to the bridge and also near its southern end. The devices would have effectively brought the entire structure down had they been detonated.

MacArthur was the Supreme Commander of Allied forces in the South-West Pacific at the time.

The bridge had been opened in 1932 after a 9-year construction period. The secret plans to destroy the bridge were intended to prevent the Japanese from easily crossing the harbor.

They were forgotten about for sixty years until they were re-discovered following the 2001 9/11 attacks on the World Trade Center in New York City.

The New South Wales Government were researching ways to protect their landmarks, including Sydney Harbor bridge, from terrorist attacks. During their research in the State’s Archives, they found a document entitled “Sydney Harbor Bridge Demolition Plan.”  The report includes diagrams on how to destroy the bridge.

Sydney Harbour Bridge under construction. Photo: CC-BY 2.0 / Photographic Collection from Australia
Sydney Harbour Bridge under construction. Photo: CC-BY 2.0 / Photographic Collection from Australia

In 1957, former army engineer Brian Nicholson gave an interview to The Daily Mail. He said that he had been ordered to determine how to destroy the bridge during the war.

Nicholson advised he was told the reason why the bridge was to be destroyed along with other measures that were to be taken to slow the Japanese progress should they invade Australia and begin advancing on Sydney or Newcastle.

Nicholson spent a day examining Sydney bridge and choosing the spots where the explosives would be placed. He determined that six men could set the devices at eight different spots on the bridge in one day. Once hooked to an electric detonator near Millers Point, a significant portion of the southern half of the bridge would be destroyed.

Once that section collapsed, the remaining portions would fall into the water. Nicholson pointed out that the bridge is hinged on each end meaning the pylons would have remained, but the sections of the deck would have swung down into the harbor.

Carl Scully is a former New South Wales Roads Minister. He found out about the plans while he was writing his biography, “Setting the Record Straight.”  A bureaucrat told him he had seen the secret plans after the 9/11 attacks. An engineer had identified design faults in the bridge during WWII that had not been noticed again until 2001.

General Douglas MacArthur und Admiral Chester W. Nimitz
General Douglas MacArthur und Admiral Chester W. Nimitz

MacArthur was assigned to Australia in March 1942 after US President Franklin D. Roosevelt ordered him out of the Philippines. The Pearl Harbor attack in Hawaii had occurred the previous December, and an attack on Darwin in northern Australia had happened just the month before.

In May and June of 1942, the Japanese fired on Sydney and Newcastle from submarines, but the bridge was not damaged although it was a target.

Sydney Harbor bridge is the sixth longest spanning-arch bridge in the world. It is the tallest steel arch bridge, measuring 134 meters from the water level to its highest point.

When planning to protect the bridge post-9/11, the NSW authorities turned to MacArthur’s plans for destroying it. They identified two points on the bridge that needed to be reinforced to prevent it from being demolished by truck bombs.

Sully said the reinforcement work would not have been noticeable to the general public. He declined to reveal precisely what points were reinforced.

The secret WWII plans are not available to the public. In fact, all plans concerning the bridge have been locked away to prevent them being viewed by possible terrorists.

Ian Harvey

Ian Harvey is one of the authors writing for WAR HISTORY ONLINE