Unbuilding the Grace and Pearman Bridges

For Sparky and myself, curiosity drives passion which in turn fuels our life's engine. Our passion was capturing the story of both unbuilding the Grace (1929 - 2007) and Pearman (1966 - 2007) Bridges and discovering the unbuilders. It takes a lot of passion to track a project from July 2005 until April 2007 - rain, shine, hurricanes or moving to Singapore. We discovered the joy of discovery learning. Ken Canty opened the front door for us - then Steve Testa, Ponch Billingsley and Mickey Rogers opened many side doors. Below are the highlights of what we discovered, who we met and what we learned.

And a reminder from T.S. Eliot (East Coker from the Four Quartets)

Home is where one starts from. As we grow older
The world becomes stranger, the pattern more complicated
Of dead and living. Not the intense moment
Isolated, with no before and after,
But a lifetime burning in every moment
And not the lifetime of one man only
But of old stones that cannot be deciphered.

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February 15, 2006: Dropping the Grace Cantilever Truss

Video

Real time video (1.3 Mb mpg)
Real time video (3 Mb quicktime)
Slow motion video (9 Mb quicktime)
High resolution real time video (8 Mb quicktime)

Chasing Curiosity

Watch the blast: Why do the girders fall faster than the smoke?

Learning Links

From Wikipedia: Air resistance or drag
From Wikipedia: Free-fall and gravity

Sparky got a head start - look at yesterday's sunset

Over today's photo spot.

Today was a fun day - warm, calm water and another adventure with synchronizing sequential photos with the ignition of explosives used to drop the Grace cantilever truss. Here is the worksite from our view at the port.

Our team (Dennis and Frank) minus Gary and Sparky (photo by Sparky of course)

The target of today's blast as well as the Testa monument to tenacity of purpose - the T-3 Pearman pier.

First, the barge had to be moved away from T-3

Then the blast. Here is the before.

Then a somewhat surprised Franchell Smalls, a Burke High student, pushed the button that made history. Ken and Mickey coordinated the timing of button pushing for our photos and helped record this moment in history
T = 300 msec (approximately) and the fire associated with the ignition process

T = 600 msec - residual indicators of ignition and you can see the right edge girder break at its cut as well as the top girder above and to the left of the diagonal truss

T = 900 msec - I am not certain if this is residual fire or whether the charges were sequenced with 250 msec delays (my guess). Continued fractionation of the truss structure

T = 1.2 sec Breakup of the center section.

T = 1.5 sec Continued fractionation of the left half of the truss structure

T = 1.8 sec The right most segment now appears to be rotating counter clockwise around the pins connecting it to the metal pier while the left section rotates clockwise around the concrete pier.

T = 2.1 sec More rotation of the right and left end structures

T = 2.4 sec The left connection to the pier has fractured and the left top girder seems to be fracturing here

T = 2.7 sec - The left section is now free falling. Look at the left splice plate position at the edge of the concrete pier cap and compare with it's location above.