applying ground motion

[SunnyPark]

hi all,

i have some errors when operating EQ analysis..

and ma question is that should i apply "mass" on the x-dir.?

if i have to apply on the x-dir., what value should be applied?

is it weight/g ?????? how about y-dir.?

[vesna]

I suggest you to read A. Chopra's book "Dynamics of Structures". He will give you the answer to your question.