Fremantle Traffic Bridge over the Swan River in Fremantle, Western Australia, near Perth (Uploader/Wikimedia Commons)

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One more boat bump could cause bridge break-up, secret report warns

5 August 2014 | By GCR Staff | 0 Comments

A busy bridge in the Western Australian city of Fremantle could come tumbling down and cause many fatalities if it sustains another hit from a passing ship, an engineering report has warned.

Frequent impacts from shipping in the past 40 years have damaged the part-timber bridge and, while these bumps haven’t caused major structural failure yet, a glancing blow from a vessel the size of the local ferry could bring it down, said the report obtained under freedom of information rules by a local newspaper.

The Fremantle Traffic Bridge opened in 1939 and is a main traffic artery into the city of Fremantle over the Swan River, whose mouth serves as the port of the larger city of Perth.

Engineering firm Arup submitted its analysis to Western Australia’s public transport authority in May. The West Australian newspaper obtained it through freedom of information laws.

Based on the assumption a new bridge would be built in the next 10 to 15 years, Arup recommended building “glancing protection frames” to shield the old bridge from boat impacts in the meantime.

A transport authority spokesman has confirmed that a reinforced steel fender system would be built next year “to mitigate impacts of glancing blows from large marine craft and to give added protection in the event of a head-on impact”.

It’s an outrageously haphazard approach to a major piece of traffic infrastructure– Simone McGurk, Australian Labor Party

New in-river navigational aids would also be installed.

Three years ago, The West Australian revealed another secret engineering report from 2004 that found the bridge was approaching the end of its serviceable life. It said the risk of collapse and multiple fatalities if a vessel hit it was unacceptably high.

That report, commissioned by the transport authority (now called Main Roads), described the risk of doing nothing to replace or upgrade the predominately timber bridge as “intolerable”. It said the risk of the bridge collapsing from being hit by a vessel was 66 times above accepted standards.

In a briefing note to Western Australia’s transport minister Dean Nalder in March, Main Roads said AUS$2m had been allocated to repair the bridge’s fendering system in 2013-14 and 2014-15.

The bridge has become a political issue in the state. Fremantle’s representative in the state legislature, Simone McGurk of the opposition Labor Party, said the state’s government had tried to hide the risks associated with the bridge and had failed to address the risks.

“Labor allocated $80 million towards a new bridge but the Liberal Government stripped that allocation and has since done a series of expensive patch-up jobs,” she told The West Australian.

“It’s an outrageously haphazard approach to a major piece of traffic infrastructure.”