Looking for a reference on what psi to use if there is no beams present at a particular level

[teach_me]

Please point me to a reference material either code or a book about Jackson & Moreland Alignment Chart when there are no beams present at an end of a column.

 

[BridgeEngineer21]

Just plugging your situation into the equation for Ψ, wouldn't it be infinity?

 

[271828]

For the sway mode of a column that is fixed at the bottom and free at the top: if you use 0 on the left in the chart and infinity on the right, then the chart gives K = 2.0, which is correct. So, if you have something other than 0 on the left and infinity on the right, then the chart would seem to give the right K.

I'm not sure the nonsway chart would apply because there's the assumption that the ends of the column don't translate relative to each other. As shown below, if there's no beam at the top, then the top of the column moves laterally. There might be a higher mode with zero translation at the top, but it's probably not relevant.

 

[HTURKAK]

If this is a real case , can you post some sketches ? Your expression implies ; if there are no beams , probably there is a ( beamless )flat slab .

In case of flat slab , you can consider frames with imaginary beams for column strips .
With your limited info. if the frame non -sway k will approach =1.0 , and for sway frame k will approach ∞.




Use it up, wear it out;
Make it do, or do without.

NEW ENGLAND MAXIM

 

[TLHS]

Yeah, what's the actual thing you're building? Is there a diaphragm? Is this a bunch of cantilever columns?