Sean Brady discusses his new podcast about structural failures and describes five failure events from history.
I’ve worked as an engineer in Australia for almost 14 years. I spent my first seven assessing aging bridges and other infrastructure, and the last seven as a forensic engineer investigating the causes of engineering failures.
I chose engineering as a career because I’d always been interested in why things “stand up” - which is ironic because now I’m more interested in why things fall down.
In my career there have been a few cases where it has been incredibly difficult to determine the cause of failure, and I get immense satisfaction in solving such problems. And I try and put as much knowledge as I can back into the profession, so that we can all learn from failure – which has been the driving force behind the Brady Heywood Podcast
I started the podcast because it was a chance to reach an audience in a new way, and when I talk about failures I want to put the listener squarely in the story of the collapse and its lead-up. I want them to ask themselves what they would have done differently.
In the podcast I discuss specific failures, identify the lessons that were learned, and look at thought provoking ideas and concepts – for example in Episode 5 I examined the rates of organ donation in various European countries, and illustrated how our rational decision making processes can be scrambled by bad systems. Then I looked at how similar factors contributed to the collapse of the I-35W Bridge in Minneapolis, Minnesota.
The podcast will definitely appeal to engineers, but I’ve also deliberately made it accessible to a wider audience. I concentrate quite a bit on the human causes of failure, as opposed to just the technical, which I think we don’t do enough of as a profession. Of course technical issues are a problem, but there are always a set of human factors that allow these technical issues to culminate in failure.
Five failures from history:
1. Hartford Civic Centre Stadium Collapse - Jan 18, 1978
The roof of this 10,000 seat stadium was almost 100 m by 100 m in plan and was suspended more than 20 m in the air on four columns. The structure started to deflect almost immediately after it was constructed, but it was ignored by the designers. They choose to rely on a new computer program and believed its results without question - even when the real structure was showing very different and disturbing behaviour. This failure illustrates that computers are a very useful tool, but they should never be a substitute for an engineer.
2. The Virgin Galactic Crash - October 31 2014
While not a structural engineering failure, the crash of Virgin’s SpaceShipTwo was caused by pilot error. But the real problem was that systems on board the craft did not cater for this pilot error. The designers assumed that top pilots didn’t make mistakes, so included no provision to prevent a simple mistake like the one which resulted in the catastrophic loss of the craft.
3. The Malahide Viaduct Failure - August 21 2009
Two spans of the Malahide viaduct collapsed because a pier was undermined by scour forces – the water essentially washed away the rock wall supporting the pier. The interesting thing was that scour had been a known issue and a managed issue on this bridge for almost 150 years. But scour details weren’t actually written down by the infrastructure owners and all the employees who knew about it had retired. So the engineers in charge had no knowledge that it was a real concern. This is a growing phenomenon called corporate memory loss and is becoming a real issue for asset owners.
4. I-35W Highway Bridge Collapse – August 1 2007
The bridge failed because of abnormal loading and a design error: some of the bridge’s gusset plates weren't designed properly – they were too thin. But the important aspect of this failure is that there were numerous opportunities to recognise the design error, but they were all missed because engineers involved assumed that gusset plates are always stronger than a bridge’s members. In this case their assumption was wrong.
5. Hyatt Regency Kansas City – July 17 1981
Few failures have had such an impact on our industry as the Hyatt Regency collapse. 114 people died because a simple, but critical, connection in a number of elevated walkways wasn't designed. This failure was the subject of Episode 2 of the podcast. I focus on the people involved to bring home how shocking and traumatic failures truly are. We look at it from the perspective of the victims, rescuers, and the engineers.
Listen to the Brady Heywood podcast.