Sections:

• feb,mar 2010: The broken Beam. Installing the patch
• allowable za range after patch
• moving into position for the patch
• truss repair schematic
• pictures of beam before break
• 05feb10: dynamic of tiedowns from telescope motion:
• tracking source, galfacts, igalfa, aeron az swings.
  
• 29mar10: new operational limits after the patch
• Min td tensions required vs za
• Allowable za range vs temp
• Minimum tensions required for various dome, ch configurations.

• sep10-feb11: the permanent beam reinforcment:
• sep10: u2-u2l3
• Table of az,za,td position, tensions during each repair.
  
• nov10-feb11 u3-L4
  
• 05feb11: finished the beam re enforcement
• feb11: computing the number of cycles the telescope has been through (2004.5 thru 2010)
  

Memos from Amman & Whitney:

• 29mar10:
• Ammann & whitney email describing the new limits
• Plot of maximum unbalanced moment vs tiedown corner tension (.pdf)
• table of member tensions capacity at maximum unbalanced moment (.pdf)
• 27apr10: tensions from A&W modelling for 29apr10 meeting in NY.
• Platform Truss table (.pdf)
• Platform Stress table (.pdf)
  
• Feed arm truss table (.pdf)
• 29apr10: A&W presentation from 29apr10 meeting (.pdf)
• 21may10: A&W non-linear analysis of cables:
  
• email from A&W
• Cable forces, margin of safety (.pdf)
• The main truss load, and stress ranges were recomputed using the more accurate cable tensions from the non-linear analysis.
  
• Main truss capacity (.pdf)
• Truss stress ranges (.pdf)
• June 10:REINFORCEMENT U1-L2-SK-3.pdf
• email
• REINFORCEMENT U2-L2-SK-4.pdf
• REINFORCEMENT U3-L4 CONN-SK-5.pdf
• REINFORCEMENT U1-L2-SK-3.pdf
  

• 08sep10:positioning sequence:az,za, td and  kips required for repair (.pdf)
  
• 10sep10: operational limits after repairs (.pdf)

Misc:

• Dome weight
• 30mar10: computing the unbalanced  moment on the azimuth arm.
  

timeline:

• 15jan10 : pictures of platform show that beam is not yet broken
• 03feb10: (wed) broken beam found
• Patching the beam
• 08feb10:(mon) threaded rods installed (this is a guess).
  
• 08mar10: moved azimuth to 296.4, dome to 8, ch to 12 in preparation for repair.
  
• 19mar10: (fri) start installation of plate across break. Finished but weld not sufficient
• 23mar10:(tue) welding redone, welding inspector ok's welds.
• 24mar10: (wed) finished removing equipment, observing starts za 6-10 deg.
• 10sep10: u2-u2l3 repair starts
• 13oct10: u2-u2l3 repairs end
• 17nov10: u3-l4 repairs start
• 05feb11: all repairs finish.

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