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.

Home Meeting St East Bay Drum Island Mt. PLeasant Pearman Stories Grace Stories Implosions Enginnering Insights Stories of unbuilders Learning Links Bridge Video Bridge Blog Unbuilding Archive All Unbuilding Segments Building the Ravenel Bridge Photo Essays About me

January 9, 2006:
An early start, loading, imploding Pearman D-24 pier and making our way back home. Morning sun is wonderful, warm and golden. It is my favorite time for capturing what happens around us.

Learning links

From NLM:Protective Gloves and contact dermatitis from nitroglycerin
The History of Explosives and Blasting
From Dyno Nobel: Shock Tube concepts
Presentation: The evolution of detonators
Shock Tube Surface Systems

Videos:

Click for Ken and Phillip loading (small format 18 Mb quicktime video)
Click for Ken and Phillip loading (large format 50 Mb quicktime video)

Early morning - and the trip out to D-24.

and Toby taking us to the worksite - always smiling

Ken is the boss today - Mickey had a fight with his appendix and the docs at East Cooper run

Early morning view of the Ravenel Bridge - golden sun

Before - and Toby - looking over Toby's shoulder. D-23 is over his shoulder. Today's job is to drop D-24 - to the right of the Ravenel support column and near the end of the Grace ramp.

An early morning look east - the D-25 stump and cousin Arthur looking on

and an early morning seagull keeps us company

and Sonny Miller is waiting in his crane to do the vertical fetching and toting.

Here is the horizontal fetching and toting - Ken (in the cage), Phillip, Bret and Toby

Our team: Sonny playing the crane, while Phillip, Ken and Bret play the dynamite - loading the basket for loading D-24

Ken and Phillip, with their protective purple gloves and ready to go

Ken and Phillip loading. The nearer column has been loaded and you can see the faint outline of the fuse lines. Here they are working down from the top of the far column.

Here, Phillip loads a stick of dynamite while in the foreground are the hanging fuse lines from the nearer column.

Click for Ken and Phillip loading (small format 18 Mb quicktime video)
Click for Ken and Phillip loading (large format 50 Mb quicktime video)

a closer look - Phillip loads a stemming bag while Ken tamps it into place.

and when all the loading is complete - here is the shock tub3 detonator array. If you have your curious eyes switched on, you might ask why some holes have a cross and other holes have an X. The X holes are incomplete. While drilling, rebar was encountered so that the hole position had to be shifted to one side or the other. The X was painted so that the correct holes would be loaded. Nice piece of documentation.

When all loading is finished, a friendly tug moves our barge.

Looking toward Drum island, you can see the tug pushing our barge as viewed from under the west Ravenel diamond

Meanwhile, on the Grace Bridge, Pio, Richie, Steve and Roy are cutting and removing more roadway.

and if you look closely, you'll see Roy in his cab and Pio in the mega-fork lift to the right.

While on the Pearman approach you can see the outline of the foundation for the Mt. Pleasant observation pier

and a closer look at Bob, Jack, Chris and Michael working on the last Pearman approach piers. In the foreground are the stumps of M1 - M5 and in the background are the support that are in shallow water - requiring a different strategy for preparation.

As the clock kept ticking - the 3pm magic moment approache. 3 toots for a 5 min warning, 2 toots for a 1 min warning , the "fire in the hole" - the blast and 1 toot for all clear. Just like clockwork.

Click for implosion video (1 Mb mpg)

Before

This ignition sequence (stills extracted from the video)

T = 0 ms	T = 33 ms
T = 67 ms	T = 100 ms
T = 133 ms	T = 167 ms
T = 200 ms	T = 233 ms
T = 267 ms	T = 300 ms
T = 333 ms	T = 367 ms - detonation just above the base
T = 400 ms - necklace propagation at the pier cap	T = 433 ms

This set of blast photos were an experiment. To see the fuse ignition, the backup needs to be in a shadow. But with a slower shutter speed because of the darker subject, there is a bit of motion blurring. Here you can see the detonation at the base and fuse ignition at the top - like necklaces around each column. So our experiment was a partial success.