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.
Ken Canty and I talked about this and Ken helped me to understand what is going on. If you look at the right side of the concrete support, you will see a pin that couples the steel superstructure to the concrete support. (Scroll up 3 photos to see a closer view of the pin)
As the concrete roadway is removed the entire bridge structure loses weight - sort of a Testa-diet. The tendancy, then, is for the concrete support to rise - since for all the time since the bridge was built the concrete support has had the weight of the bridge on it.
So, if enough weight is removed from the bridge, all the stresses will be concentrated in the two coupling pins. To assist the bridges integrity, the steel superstructure is couple via the tiedown cables (see the beam that link the short beam resting on top of the transverse girder (on either side) with a similar beam under the concrete cross member.
This work is licensed under a Creative Commons License.
C. Frank Starmer