June 6, 2004: 4th Cable Stay (west platform),
East side platform extension (resting on the west pylon) and
West tendon termination. Note the platform with the blue wheel - for
preparing cables to be pulled up the stay pipe.
East side platform extension of the west pylon platform
(July 11, 2004 note: There are no obvious counterweights because of the near
symmetry (4 anchor extension segments in each direction)
in westward-directed platform weight and the eastward-directed
platform weight even though the cross beams for the eastward-directed segment
were not yet placed.
Two stacks of concrete blocks, acting as counterweights are quite obvious on
the July 04, 2004 photos when the eastward- (5 anchor extension
segments) and westward-directed (6 anchor extension segments)
platforms were asymmetric in length
Tendon termination and stressing (west pylon)
"With regards to the ports at the bottom of the photo, these are actually
post tensioning cables (actually referred to as tendons). These tendons do
exactly what you suggested. They are tensioned to the proper force with the
large hydraulic ram you have pictured on your website and I have included
below. This ram is only used temporarily and after the proper force is
applied a wedge is used to hold that tension in the tendons permanently. I
was unable to find a good picture of the actual wedge and tendon
arrangement. That tension holds the legs of the tower together and keeps
them from "kicking out". As you can imagine, with thousands of tons of
concrete and road deck on top of these legs they would tend to spread apart."
This work is licensed under a Creative Commons License.
C. Frank Starmer