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October 19, 2020

Lessons from The West Gate Bridge Collapse

West Gate Bridge

Last Tuesday marked the latest construction death in WA – when a glass canopy collapsed at a construction site at Curtin University, killing a young apprentice and injuring several others.

Last week also marked the 50th anniversary of the West Gate Bridge collapse in Melbourne that took the lives of 35 construction workers and engineers.

The Royal Commission into the West Gate Bridge collapse would have ended with sufficient comfort that such accidents would be unlikely to occur in the future. The idea that people were still dying on construction sites fifty years into the future would have provided no comfort for those that had lost loved ones and wished for no-one else to suffer their pain and loss.

West Gate bridge Memorial

West Gate Bridge Memorial

And yet here we are, in 2020, still losing valuable lives in the interests of economic and social growth.

All accidents could have been avoided – hindsight has 20/20 vision after all, but hindsight in one instance doesn’t seem to become foresight in another.

There’s little we know about last week’s collapse, and it’s likely that the lawyers will keep their secrets for several years to protect all those responsible, so learning from such disasters is a long game. 50 years long though?

The West Gate bridge was an interesting engineering catastrophe that we do know a lot about. Let’s dive in…

The West Gate Bridge began as a vital link between Melbourne’s CBD and the western suburbs. The second-longest in the country, it was two years into its construction when it became Australia’s worst-ever industrial accident.

Critically weakened by a series of engineering and construction failures, a giant 2,000 tonne section of the bridge collapsed in October 15th, 1970, killing 35 construction workers and engineers.

West Gate Bridge Collapse

For some of the construction workers that survived the collapse, painful memories of their fellow colleagues trapped in the wreckage dead or battered and broken still haunts their memories.

What Lead to The Disaster?

The West Gate Bridge was a box girder design bridge. Many of its segments were prefabricated sections that were floated over the Yarra river and then lifted in place by cranes.

Its construction started in early 1968 and within two and a half years, the two sides of the bridge finally met in the middle. But there was a problem: one side — the north — was 11 centimetres higher than the other!

To try to fix the problem, the construction engineers thought by loading the higher side of the bridge loaded with 10 massive concrete blocks weighing 8 tonnes each, it would effectively push that side down to the correct height.

They were wrong! 

The process caused a buckle in the bridge, which then the engineers tried to fix by removing a numbers of bolts to ease some of the stress on the structure.

West Gate Bridge Bolted Connection Pieces In a Memorial

The bridge collapsed 10 minutes before midday taking 35 workers to their deaths.

The first section of the 110-metre span of the bridge that hit the ground landed on huts where workers were having their lunch, crushing the men instantly.

Another section fell on diesel tanks at the site, triggering a huge explosion that could be heard kilometres away.

West Gate Bridge

A landmark familiar on the horizon for the last two years was gone.

Crews worked for days after the West Gate Bridge collapse to remove wreckage and retrieve the bodies of those who died.

One of the men who died was trapped beneath scaffolding that had fallen into the river and was only found eight days later, floating to the surface when the structure was lifted out of the water.

A Turning Point for Workplace Safety

A Royal Commission into the disaster was scathing of the design and methods used by the two companies building the bridge, John Holland and World Services, and the attempts to rectify the bridge’s flaws.

Riggers on the project prior to 1970 worked without harnesses and welders shielded themselves with material made from asbestos.

If the workers had concerns about safety, they had little option but to strike — an issue raised in the Royal Commission’s final report, but framed as a criticism of the workers themselves.

West Gate Bridge Workers

“For their behaviour on the contract,” the report read, “the unions and men must bear their share of responsibility for the tragedy that ensued.”

It was a criticism that rankled the workers at the time, and still sits uneasily with those who survive today.

Many in the construction industry trace improvements in the field — particularly in workplace safety and compensation — back to the West Gate disaster with measures that had been adopted on the recommencement of the West Gate Bridge project in 1972 later enshrined in Victoria’s Occupational Health and Safety Act introduced in 1985

“You didn’t have the process that you have today,” said Pat Preston, who went on to become the manager of the construction union’s health and safety division years after the accident.

“You’ve got health and safety legislation, you’ve got a process. We didn’t have that. If you were concerned about something and you got a flat no, you just didn’t have any other means of redress,” he said.

Fast Forward to 2020 - What Have We Learned?

Plenty, to be fair. We know much more about the behaviour of slender and stiffened plates, buckling and torsion, and moreover, we have (and depend on) complex structural analysis software to not only predict failure with more accuracy but also to investigate constructibility issues, model the site and structure and ensure with more certainty the positioning of the structural elements.

From Engineers Australia Create magazine:

University of Sydney Professor of Practice (Bridge Engineering) Professor Wije Ariyaratne FIEAust said there is a universe of difference between a half-century ago and now in terms of bridge building safety.

Design codes, such as AS 5100, are much more comprehensive, Ariyaratne said.

He added that there have been important advancements in construction specifications, technology, onsite construction practices and stringent work health and safety regulations. And there is much more accountability for everybody from the site worker all the way up to the owner, he said.

“As a result of this evolution or development, one of the most important things is the safety in design, which was not there at that time [in 1970],” explained Ariyaratne.

“Any project, it doesn’t matter how small or how big, how simple, how complex: you have to go through this process. There are workshops after workshops after workshops to evaluate the risk. What are the issues that you have incurred in constructing this design? What is the safety? What are the drawbacks?… We have moved a long way in the right direction.”

Mmmm. I believe that to a point. But try telling that to apprentice glazier Jonnie Hartshorn’s family. Sadly, the it may just be that the voices of a concerned few were ignored, or at least not taken seriously, by those hell-bent on delivery.

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