Equalizing the tiedown positions after removing the lead.


    The lead in the corners of the platform and the laser shack were removed for the painting project. After the project we decided to not replace these. The removed weight was about  20,000 lbs. We need to replace this weight with tiedown tension to level the platform. This will give more  pretension in the tiedowns (at least 12 and 4). When the dome (at high za) passes in front of a tiedown, this extra pretension will help not loose tension in the cable so soon.
    Tilt sensor az swings were done and the 1 azimuth term amplitude was measured. This tells how "uneven" the tiedown positions are.

We want to have all of the extensions be the same and to have the tensions in the cables unchanged (so we are still balanced). We moved all the tiedowns to the td12 position. This required the NUTS on the cable Ubolts to be moved in the opposite direction so the tension remained the same. The motions were:

We need to worry a little about the dynamic range:

tiedown parameters
degF per platform inch
Kips/platformInch (no loss td tension)
Kips/platformInch (add weight to platform
and don't readjust td for lost tension).


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