Repairing platform broken beam 2010

Section links:
17mar10: allowable za range, tiedown tensions for mar10
8mar10: moving the dome,ch,az, tiedowns into position.
8mar10: truss repair schematic with 8mar10 updates (.pdf)
15jan10: pictures of beam before break.
Dome weight
unbalanced loads on azimuth arm



 A beam   connecting the upper and lower cords of the platform was found broken on 03feb10.  Looking from corner 12 to the tiedown (td)  back stay connection point it was the left back stay cable and it was the rightmost beam of the pair of beams. The break was right above the connection of the back stay cable to the flange (which connected to this and two other beams forming a triangle).

17mar10: allowable za range, moments, tdkips after beam fixed.

    The patch on the broken member was completed on 17mar10. After this, ammann and whitney would like us to limit the telescope motion so that:
    On 17mar10 az swings were done to find the azimuth arm balance position.
The plots below show the az,za,temp,td range we can use  and still meet the above constraints.

  The za range that the dome and ch can move(.ps) (.pdf):
The temperature range we can keep 20kips in each td (.ps) (.pdf):
processing: x101/100317/

8mar10: moving the dome,ch,az, tiedowns into position.

    On 8mar10 we moved the tiedowns, az, dome,ch into position to  relieve tension on the broken beam side in preparation for the welding. The starting conditions were:
processing: x101/100302/

Images of the broken beam

15jan10: picture of beam where break occurred.

    On 15jan10 tom balonek took some pictures of the platform.