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.
More innovation and Harvesting girders
Bob McCabe's group (Jack Foley and Scott BIllingsley) is at it again with more innovation. Here is the worksite and note that the current work area for removing roadway and girders is over a sensitive wetland area
The problem: how to remove the roadway with minimal debris falling into the water below? Bob's team came up with the idea of using the concrete saw and making longitudinal cuts along the middle of the underlying concrete girders. While the experts said it could not be done, Bob's team had an idea. On the top of each girder are rows of stirrups, each an inverted U, that is for tying rebar between girders and forming the grid used to strengthen the concrete. As an example, here is the rebar grid for the Morrison St ramp.
The innovation was figuring out how to cut exactly down the middle of each concrete girder and then make transverse cuts so as to make rectangles of roadway. A 345 grapple pulls on the precut segments until the remaining rebar fails allonging removal of the roadway segment. This harvesting procedure (I hope to catch maybe tomorrow) results in a stack of harvested segments as shown here.
Here is a girder with one sling attached and one loose end
and Stan and Nathan making their way out to secure the sling
This time the man basket brought a team up to assist in wrapping the sling around the girder
which was much more efficient
With the sling attached to the yoke at each end - the girder is ready to lift - almost.
First, Jack brings is 345 shear in and breaks the attachment at this end
then gently bites the girder and the lifting begins
and more lifting
The crane (below) rotates the girder so that it can be placed on the roadway surface
and lowers it into place - in order to release the slings.
shown here. For an animated view of this click here for an 8 Mb mpg I stiched together from the individual photos
In comes Jack
to take a bite. I stiched together another mpeg video (6 Mb) illustraing Jack's eating habits
then the segment is passed to Scott.
who transports it
to the open air barn where the harvest is kept
This work is licensed under a Creative Commons License.
C. Frank Starmer