Gantry A-Frame - Upright - Column End Conditions

[franklineng]

If you were designing a mobile gantry with the side structure being typically an A-frame, would both ends of the vertical column be considered as "fixed" end conditions.

 

[GBor]

There are many ways to design a mobile gantry. Are you suggesting that you are analyzing a single vertical beam of the gantry and are trying to consider the fixity for simple beam calculations? Typically, I don't consider either end "fixed" (no rotation), but I have to look at the geometry to get a true opinion of the structure.

Garland E. Borowski, PE
Borowski Engineering & Analytical Services, Inc.
Lower Alabama SolidWorks Users Group

 

[franklineng]

Yes, basically I am analyzing a single vertical beam and considering the fixity for simple beam calcultions. So would you consider the end condition as being pinned?

 

[GBor]

For a conservative stress, I would analyze it as fixed. For deflection, I would assume pinned, or perhaps even cantilevered, but gantry design is clearly non-trivial. Simple beam calculations may get you in the "ballpark", but I wouldn't count on it for actual design.

 

[mrMikee]

For a gantry that runs on a rail or tires I would assume the the bottom end of the column pinned in the direction from side to side. In addition I would be reluctant to consider any side thrust developed at the bottom of the columns due to the ability of the wheels to "walk" in or out when there is a horizontal thrust. There are other practical considerations to take into account when designing gantries and GBors comment that the design is non-trivial is in my opinion good advice.

Regards,
-Mike

 

[MikeHalloran]

Rule 96:
Anything that _can_ be hit with a forklift, _will_...


How it responds is up to you.



Mike Halloran
Pembroke Pines, FL, USA