February 22, 2006:
Lowering the Pearman main span over the
Cooper River
Sparky and I started at 6:30 this morning and I returned home about 6pm. What
a day - success all the way around. The story is slowly coming together,
but here is how it started. A perfect start of what was supposed to be
rain.
Sunrise over Jimmy Grier's Drum Island Team cleanup - not much left
of the Grace of last Friday
Sparky and I hitched a ride with Susan and Manny
The worksite from Drum Island.
The worksite showing both the Pearman (foreground) and Grace (background)
main spans
In parallel with what I was watching on the Mt Pleasant side was another
team working on the Charleston side
To lower the main span, first it must be disconnected from the east
and west cantilever sections. The main span is coupled to each
cantilever section at the splice plat at the top and at the
bottom. To the upper and lower girders must be cut - as well as the
vertical beam coupling the upper and lower pins.
The orange marks identify the locations of the cuts
Part of the ironworker team - Chris, Derek Jost from
Mammoet (pronounced Mamoot), Speedy, Mike and Charles
Derek (Mammoet), Stan, Manny, Speedy and Nugget. Stan, Speedy and Nugget
are famous for their Pearman acrobatics when harvesting concrete and
steel girders
Lewis (in the foreground) worked on the Ravenel Bridge and I caught
him several times with Philip working around their crane: Last Dinasour
Standing. In the background is Richard Smoak (left) and Chris Barrett (right)
Making final cuts at the base.
progress with the base cuts
Cutting the top box girder
about 1/4 complete
about 3/4 complete
Manny, our friendly crane operator and Robbie
After the cutting was complete, the barges were repositioned and the Cape
May placed under the Pearman main span. Large vertical pipes called
spuds are used to hold the barges in position. Here Speedy and Chris
were positioning the cable so that Manny could lift the spud.
At the other end, Scotty was working with the back spud
Frank and Charles after the barges had been repositioned.
Looking west at the jack setup
Looking at the east setup
and looking down
While cousin Arthur is looking on
The east (left) and west (right) jacks
The Cape May is the receiving barge directly under the Pearman main span
The west assembly just after the start of lowering
The just completed cut
At the roadway level - the gap between the beams that tie the pins together
The Cape May
Inside this innocent cargo box is the computer and pilot
for controlling the hydraulic jack
The display shows the position of the jack for each of the four assemblies.
And here is the magic wedge that fits around each cable and controls the
advance of the cable as the upper and lower wedge assemblies are adjusted.
This 3 segment cone fits around the cable with the smaller end
pointed down.
As shown on the below - the wedge fits into a wedge plate such
that increasing tension results in greater interface pressure between
the wedge and the cable. This prevents the cable from slipping.
The Mammoet wedge
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The Freyssinet wedge (used on the Ravenel Bridge stay cable assemblies).
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Examples of the wedge, cable and head
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Here is a video of
Mammoet, Cashman and Testa Lowering the Mainspan (31 Mb mpg - be patient).
And lowering starts at 9:56 am
A baffle was stubborn
but easily resolved
Then continued lowering
lower
lower
lower
and down
A view of the downed main span from the west
Joe Duffy assessing the downed main span
The cable coupling is detached from the south side
and the north side
Scott and Abdi talking while Mike looks at both coupling units
Here a diver is retrieving the stubborn baffle
Ah ha - bubbles mark the spot
The diver emerges
the rope is attached to the crane
and up up and away
Scott detaching the retrieval rope from the crane
and the stubborn baffle
Sparky - who has become an essential part of telling the unbuilding
stories - with Speedy (left) and Scotty (middle) and their unseen iron worker
colleagues who have brough a lot of new life to us and are
essential players of telling these stories
Bud Skidmore from SC-ETV has also been a wonderful story-telling companion.
Here was his vantage point from the Ravenel Bridge
Sparky is a very young man and has greater endurance than I do, Here is
his bird's eye view of shipping the Pearman main span up the river
Initial separation from the worksite barge complex
Moving away
and going home to the Navy Yard
with pleasant company
Meanwhile, I'm beat - and Cynthia gives me a ride back to the Sea Breeze
a look at the after - bathed in the late afternoon sun
Cynthia and cousin Arthur
A view of the Ravenel Bridge without the Pearman main span
and Jim Grier's group is still at it with the Drum Island cleanup. To the
right of the Grace pier is what remains of Tenacity of purpose, the
stubborn 3-layer rebar Pearman pier (D3)