OK, thanks everyone. It turns out I WAS doing things correctly and had descended into a deadly spiral of second guessing myself all over the place.
@paddingtongreen's slap in the face brought me back to reality - the equilibrium forces all check out, there's no need to pin anything (except the...
This question emerged when I was looking for base reactions for slab design. The magnitudes of the results were quite large, because all joints were free to move. Also, joint reactions throughout the model were zero, except for the rigid foundations. Danger signs, I thought.
When I pin the...
Yeah, that's the problem...
Loads are working fine when there's movement allowed in the joints.
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The part where I'm confused is, if every bolted joint is essentially identical, what's the basis for assuming pinned or free? It seems I'm just arbitrarily picking joints to move freely.
I'm modeling a house in SAP2000 with a steel frame that is bolted together. I've assigned rigid joints to the foundation connections, and pinned joints everywhere else.
Now, there are no deflections at the non-internal joints, and my model acts "frozen". But, joint reactions are present...