The Minneapolis bridge collapse and connection shear on the Clyde Arc will yield valuable lessons for the future, says NCE's editor, Antony Oliver
This week's report into last August's I-35W bridge collapse in Minnesota must remind us that we ignore proper infrastructure inspection and maintenance at our peril.
While clearly the investigations have identified some significant problems with the original design of this structure and its ability to cope with subsequent modifications, these can't be allowed to mask more fundamental asset management failings.
I fear that this could happen. To say that "I-35W collapsed because of a design fault" is more easily understood and acted upon than "I-35W collapsed after years of inadequate structural inspection and maintenance".
It is vital that any investigation into a bridge collapse or structural failure – not least one this catastrophic – looks in detail at all the angles and the possible causes.
Whether we are talking about I-35W-scale collapses or events on the scale of last week's Clyde Arc connection failure, there will always be useful lessons to learn.
But just as the investigators at Clyde this week will be trying to discover not only that the connection sheared but also why it sheared, investigators in the US must remain focused on why the I-35W bridge chose that particular moment in its, albeit under-designed and non-redundant life, to collapse.
Fortunately a collapse on the scale seen in Minnesota is very rare. As such it provides a unique and very real opportunity to test structural theory and learn lessons for the future. Of course it is therefore crucial that the official investigation report exposes any possible design
defects within a complex and non-redundant structure such as I-35W.
Engineers in the US and around the world – not least in the UK – should not be left with the impression that by identifying any specific design flaws the collapse somehow became unpreventable.
In short, the public's need for a "head to roll" should not be allowed to hide the more serious and potentially dangerous problem of maintenance underinvestment.
There can, after all, be little doubt that the US has been struggling over the last couple of decades to provide sufficient and appropriate funding to maintain its vast amount of public infrastructure. And while there are most probably very real questions marks over the specific sizing of various elements of the I-35W structure, we should not overlook the other maintenance related issues when drawing conclusions and learning lessons.
Not least because we are not really that much better in the UK when it comes to properly funding and managing the maintenance of our infrastructure assets.
We must therefore ensure that we use this kind of disaster to not only learn engineering lessons but also to teach our political masters. As they say, a stitch in time…
Antony Oliver is NCE's editor