A doomed design was the “probable cause” of the horrific collapse of a pedestrian bridge in Miami last year that killed six people and injured 10, the National Transportation Safety Board found Tuesday.
A peer review that failed to detect the calculation errors by designer FIGG Bridge Engineers – and an engineer’s failure to recognize the importance of cracking before the collapse – contributed to the tragedy, the board said.
My initial thoughts when I heard about the collapse were:
A lot of companies have subcontracted out the actual work – designing, building, manufacturing, operating, maintaining – and instead busy themselves with “managing” the whole process. This involves lots of well-educated people in nice clothes sitting in glass-fronted office buildings sharing spreadsheets, reports, and PowerPoint presentations by email and holding lengthy meetings during which they convince one another of how essential they are.
In such an environment, it is inevitable that the quality of work suffers, errors go unnoticed, and – occasionally – catastrophes occur.
So I got the errors going unnoticed part right. I also said:
I’d be willing to bet a hundred quid the calculations and finite element modelling were done outside the US to save money, or subcontracted to another company, and supervision – which involves expensive Americans – was at nowhere near the levels it should have been. Regardless of where they were done, I’d also be willing to bet the company spent more manhours on progress meetings and overly-detailed weekly reports to let the management know what was going on than they did checking the engineering calculations.
Here’s what the article says:
NTSB staffer Dan Walsh said the construction was “high-risk” because of the complex design of the bridge. But he added that the school was overseeing the project, and the state Transportation Department was not required to have an inspector on site.
“Our recommendations address this issue, that FDOT should have more authority on this type of project,” Walsh said.
Uh-huh. The school awarded the job to MCM, perhaps on the basis of a glossy brochure on how committed they were to diversity and inclusion, and MCM handed the bridge design work off to FIGG and didn’t bother to supervise them or make sure their calculations were sound. Nor did they think anything was wrong when FIGG started tensioning the bridge trusses over live traffic, which would have had me blowing whistles and waving red flags without knowing the first thing about bridges. Result: collapsed bridge and dead people.
The board issued several recommendations to ensure that additional guidance will allow designers to better determine loads; that plans will undergo peer review by a qualified independent firm.
This doesn’t happen already?! When I got a crane built for an oil company in Nigeria, I used a specialist crane design company in the Netherlands and then got the entire design, including the calculations, verified by an independent third-party certification body. The same outfit also witnessed the load test and signed off on it. I thought this was standard.
FIU President Mark Rosenberg lauded the project when the section was dropped into place days before the tragedy.
“FIU is about building bridges and student safety,” Rosenberg said. “This project accomplishes our mission beautifully.”
If an accident happens on an oil and gas construction site resulting in fatalities, the oil company is ultimately responsible because they own the job and they are obliged to use competent contractors thus ensuring the safety of all workers. They aren’t permitted to just point at the engineering and construction contractor and say “nothing to do with us”. This is why BP got clobbered for the Deepwater Horizon accident more than Transocean who owned the rig. Perhaps it’s time this ownership principle was extended to civil works in public places?