Interstory Drift Checks

[Galambos]

I am curious how other firms check interstory WIND drift and would like to conduct an informal survey. We use a 10yr event with P Delta effects, but there are variations between engineers within our office.

1. Do you check interstory drift at the building extremities, at the frame, or at the center of gravity?

2. Do you check interstory drift for all ASCE wind load directions (X Dir, Y Dir, X Dir with Eccentricity, Quartering Winds, etc.)

3. Do you check the resultant of the X and Y displacements?

 

[asixth]

What is the magnitude of building that you design.

I did a single level structure recently braced by cmu walls. Because the stiffness was not symmetric I was getting a greater drift at one end of the floor slab, so that resultant deflection of X and Y is what I used to check drift.

 

[slickdeals]

Torsionally sensitive buildings have a problem. I heard the problem with Hurricane Ike in Houston was that buildings that were not stiff torsionally had their windows pop out during the hurricane. Its easier to pop a window when you are able to twist the building.

 

[WillisV]

I check x and y components separately at the building corners. Its all a matter of engineering judgment though...