(08-04-2009, 08:26 AM)reynand_d Wrote: I just want to share how I check my model in etabs and correct me if I'm wrong or advice the proper way:

1.)Gravity

make a safe model for slab which is the thickness
= no. of storey x slab thicknness in etabs model

Apply the area load
=no. of storey x average area load apllied in etabs
(THE CONCEPT OF THIS IS I COMBINED ALL THE SLAB AND MODEL IT IN SAFE AS 0NE SLAB)

Reaction in etabs should almost equal to the reaction of safe.

Or, roughly compute the reaction at base manually(by tributary area method) then compare to etabs reaction result




2.) Wind

Go in show deformed shape then choose the Wx and Wy(one at a time) then click the top corner of the building then right click to see the point displacement. This value should less than to the allowable lateral deflection, in ubc H/500, H is the total height of the building.


3.) Earthquake

Actual drift should be less than to allowable drift

allowable drift= 0.7 x R x 0.020 x story height
(with the period of less 0.7second)

= 0.7 x R x 0.025 x story height
(with the period of equal or more than 0.7second)
R= overstrenght coefficient form table 16-N of UBC 97 PART 2

Based in UBC 97 code

I have less experience in high rise..I not yet try to check the drift, Anybody can discuss how to get the actual drift and what load combination used in UBC 97 code in getting the actual drift.