Column Base as Fixed or Pinned

[n8engr]

Let's say the bottom of your column member has a 4 bolt base plate connection to the foundation. Do you consider this as a fixed condition or a pinned condition.

At what point do you consider there is some rotation at the base plate for which a moment or fixed condition would not be appropriate?

Thanks for the help.

 

[Struct71]

Depends on the structure above the columns-

if the structure is much stiffer than the average bolted connection than I would consider it pinned.
(EG average portal frames, utility, building frames etc)

 

[SteveGregory]

If the anchor bolts are closely spaced or between the flanges, then it should be considered pinned.