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I once worked on a project that went badly off track. It involved a digital communication system conceived back in the days when radios were usually analog devices. The digital approach, it was thought, could be better on a variety of fronts. Working with bits would be easier and quicker than trying to tweak analog signal paths.
The idea of an easier way to design radios sounded great; Management constantly griped about how long it took to perfect designs. So the whole effort was put on an accelerated development schedule.
Yeah, right. Optimism faded fast with the release of the first hardware prototypes. In a nutshell, they only worked on the test bench. In the real world, the noise environment cut the effective range to a laughable figure.
The fundamental problem with the whole effort was that we underestimated what we didn’t know. Digital radio was a relatively new idea. A lot of the know-how about how to do it hadn’t migrated much past academic papers. It was also tricky to get digital RF to work back then because discrete components made up most of the circuitry. After a lot of wheel spinning, gnashing of teeth, and embarrassment among project managers, the so-called accelerated schedule turned into one extending about twice as long as a normal.
These bad memories came back as I learned about the collapse of the pedestrian bridge at Florida International University. The method used to construct the bridge had the unfortunate moniker of “accelerated bridge construction,” or ABC. The “acceleration” simply refers to the practice of building the span near the bridge site, then moving it into place onto its supports, thereby minimizing road-closure time.
Ironically, ABC arose partly to boost bridge safety – with one in nine U.S. bridges rated as structurally deficient, there’s a need for methods that help replace them economically. And with 87,606 vehicle crashes in work zones during 2010, methods that minimize work zone disruptions also reduce traffic fatalities.
One unintended consequence from the FIU bridge catastrophe is likely to be malevolent undertones attached to anything with the label of “accelerated.” The tenor of some media reports written in the heat of the tragedy might lead readers to think an accelerated method is one that is slapdash. This isn’t at all the case for ABC, a fact that becomes clear from a review of the website for FIU’s Center for ABC. It’s clear that ABC technology is much farther along than the digital radio concepts that tripped us up many years ago. On the FIU ABC site you can see studies of ABC techniques done on shake tables, in wind tunnels, in seismic regions, and in other situations that demand a careful assessment of risks. There is nothing hurried or haphazard about ABC.
The loss of life at FIU is tragic. There should be sympathy not only for the victims and their families but also for the engineers and construction personnel involved. I’ve seen first hand the kind of stomach acid that a major project-gone-bad can bring even when the only casualties involved are careers and egos. Undoubtedly the professionals associated with the FIU bridge collapse are experiencing nightmarish levels of stress and self-doubt.
Readers with religious beliefs might consider remembering both victims and bridge builders in their prayers.