Thursday, February 7, 2013

The Romans Built Better Bridges than the Tennessee Department of Transportation

So, downtown in the Big-City-Down-The-Pike (Knoxville, Tennessee) they are pretending to rebuild a bridge.  The history of this bridge is shrouded in mystery.  For starters, we know original construction began on September 30, 1930.  That date is recorded in numerous places, including WikipediaHowever, ground breaking was on September 24, 1930 in the midst of, apparently, endless scandals.
Progress photo, 1 DEC 1931
Now the rest gets murky.  The completion "date" was somewhere in 1931.  Apparently December 1931, because every reference says it was "completed in 1931," or something similar, and a little digging uncovered the photo above, where it does not look quite complete on the 1st of December.  So-far, no source is owning up to a precise completion date.

Fast forward to the 21st century: Big-City-Down-The-Pike decides to "restore" the big bridge.  With modern equipment and engineering, the Henley Street Bridge Project began sometime in 2011, as you can see from the link.  Silly me, I thought engineering involved exacting specifications.  I suppose noting the beginning of the project within a 365 day window is close enough, and an order of magnitude greater than merely mentioning the decade.  The photographic evidence seems to indicate somewhere around January 3, 2011.  Completion date?  Sometime in 2013 February 24, 2014.  So, let's figure out the calendar, that is roughly three times as long as it took in 1930/31.

In the course of researching this story, and hearing about this public works project on the radio every week, there seems to be some sort of concrete preservation strategy going on.  Rather than knocking down the old bridge and building an identical one, or [gasp!] building a better bridge, the bureaucrats-that-be decided to chip away the bits that are crumbling, presumably to preserve the endangered concrete, then weld in some new re-bar and pour new concrete over it.  As of this writing, and two years of reconstruction, it looks like this:
7 FEB 2013
One would think that some sort of technological advances had happened since 1930.  Unemployment is not much different, so there were plenty of construction workers available at rock-bottom rates (if taken) both times.  But, somehow, some way, this bridge takes three times as long to build in the 21st century as it did in the 20th.

The latest news is: endangered concrete is not the sturdy stuff that lasts forever under water as originally thought.

When authorities closed the bridge in January 2011 for the $24.7 million renovation, they expected the structure to reopen no later than June 30 this year.

Workers in December, however, discovered deterioration on the three sets of pillars in the water that exceeded expectations, said Wayne Seger, director of the bridge division for the Tennessee Department of Transportation.

The troublesome piers are 3, 4 and 5, which are numbered from the north side of Fort Loudoun Lake.

Seger said authorities decided it best to rebuild the three piers rather than try to patch them.
The Romans built bridges better!  They were probably quicker about it too, but I've not been able to find how fast they worked.
The Alcántara Bridge, Spain, a masterpiece of ancient bridge building via Wikipedia

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