Beam geom. input in PCACOL for slender columns

[DukEngnr]

When designing a slender column with PCACOL, the program prompts for the x-beam and y-beam geometries at the top and bottom of the column.

What do you do if in one direction you just have a flat slab? Do you assume a 'beam' width equal to the dimension of the column, and that the slab provides some rotational restraint? Or is that an invalid assumption, and it is best to use the option in PCACOL for 'no beam specified'.

Thanks,
CS

 

[JAE]

The slab adds some stiffness so using it as a pseudo beam is fine as long as you use the correct properties - take into account span, effective width and Ie.

You could also ignore the slab if it is significantly weak compared to the column.

 

[blake989]

I agree. Include a width of slab equal to the width of the support in that direction. With the relative stiffness of a slender column, you may underdesign either the column or the column strip of the slab for patterm loading or if this is a frame.