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.

November 30, 2005:
Imploding Pearman Pier D-25

It was a long long day - starting about 6:30 this morning - a day to watch the loading of D-25 and the implosion. After putting this together, I visited Google using dynamite sequence control - and found two really good tutorials.

Learning Links

We made several video options revealing the dynamics of today's implosion of D-25:

What was remarkable to me was how the sequencing of the detonation was controlled. Watch how Mickey's team loaded and fused the explosives. Here is the implosion sequence from still photos and from frames of the video.

t = 15:53:08

Here you can see the detonation sequence progressing upward - t = 15:53:09

I extracted each individual fram from the video (30 frames/sec) in order to explore the individual ignitions - as shown below. Every frame is not shown - but I have indicated the time of each frame assuming 30 frames/sec. The bright (sort of) dots and lines are the individual ignition events - better seen in the shadow portion of the two columns.

t = 0, 0.033, 0.067

t = 0.100, 0.133, 0.233

t = 0.367, 0.533, 0.600

t = 0.633, 0.700, 0.733

t = 0.800, 0.867, 0.900

t = 0.933, 0.967, 1.000

t = 1.033, 1.067, 1.100

t = 1.133, 1.200, 1.233

At this point, the lower 300 ms delays have kicked in and the base starts to ignite - looking like the upward directed base dynamite ignition is chasing the upward directed fuse ignition.

t = 1.267, 1.333, 1.367

t = 1.400, 1.433, 1.467

t = 1.500, 1.600, 1.633

t = 1.667, 1.700. 1.733

t = 1.767, 1.800, 1.833

t = 1.967, 2.100, 2.633

and here the cap ignites

t = 2.700, 2.733, 2.800

Here you note almost no vertical component of the blast - t = 15:53:09+

t = 15:53:10

t = 15:53:11

t = 15:53:12

t = 15:53:28

t = 15:57:49

With Cousin Arthur smiling his approval - all that remains is the lower support - which will be the target of a separate preparation and detonation.

And of course - transport courtesy of Sharon.

and a view of the Ravenel Bridge without D-25 in the background

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This work is licensed under a Creative Commons License.

C. Frank Starmer