Changing the face of Charleston : The unbuilding of the Grace and Pearman Bridges
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Unbuilding Highlights
(Apr 10)
Meeting St. Stories
(Jul 10 2006)
East Bay Stories
(Oct 10 2006)
Drum Island Stories
(Feb 17)
Pearman Bridge Stories
(Apr 3)
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(Apr 3)
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(Mar 27)
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(July 23 2006)
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(Feb 28)

February 15, 2006: Dropping the Grace Cantilever Truss

    Chasing Curiosity
  • Watch the blast: Why do the girders fall faster than the smoke?
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.

T = 3.0 sec - just plain free fall

T = 3.3 sec

T = 3.6 sec Cue the seagulls

T = 3.9 sec

T = 4.2 sec

T = 4.5 sec

T = 4.8 sec

T = 5.1 sec

T = 5.4 sec

T = 10 sec It is all over. Gone is Grace's Drum Island cantilever truss.

Gary Eaton saw the blast from the other side and here are his photos


T = 0

T = 0.3 (approximagely)

T = 0.6

T = 0.9 - From Gary's position, the fracture of the floor structure is quite evident

T = 1.2 - as well as rotation of the right side of the truss counterclockwise around the concrete support pier.

T = 1.5 - here you can see (I think) the attachment to the right concrete pier fracture - the horizontal beam seen above is gone.

T = 1.8

T = 2.1

T = 2.4

T = 2.7

T = 3.0

T = 3.3

Packing up and back to work

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Attribution: C. Frank Starmer and Sparky Witte from