g is the force via acceleration of gravity.  So 1.4g is 1.4 times the force of the acceleration of gravity.

JAE!

For Example
SS = 0.60g, and S1 = 0.40g.

Let's be site classification of ‘Class C’
If we determine Site Coefficients, Fa and Fv.  then
Fa = 1.08
Fv = 1.40

So, Adjusted Spectral Response Accelerations:
SMS = Fa(SS) = 1.08(0.6) = 0.65
SM1 = Fv(S1) = 1.40(0.40) = 0.56

So, Design Spectral Response Accelerations:
SDS = (2/3)SMS = (2/3)0.0.65= 0.43
SD1 = (2/3)SM1 = (2/3)0.56 = 0.37

To determine Seismic Design Category. With SDS = 0.43, SD1 = 0.37,

then, What is the Seismic Design Category ?

It's "C" ( from IBC 2000, Table 1616.3(1) and Table 1616.3(2))

Actually question is;
even though SS = 0.60g, and S1 = 0.40g., we don't use this "g" in the rest of the calculations.

Then why is the "g" there?

BR
Tharani

In the case you're speaking of, they are using "g" more as a unit than a variable.  Truly, if you have 0.60g, it is stating that your acceleration is 60% of gravitational acceleration.  However, in IBC terms, the g in this regard is being used as a unit.  When you discuss earthquakes, it is customary to discuss in terms of g (e.g. 0.4g, 0.6g, etc..).  If you didn't use a unit of "g", it wouldn't make since when you stated that there was a 0.6 earthquake.  0.6 what?

Hope this helps.

Mike

Yes Mike!

This makes sense.

But, i don't know ,why, in IBC , They use different formats.
in some Tables, they use 0.xg, in other Tables, they use just 0.x for spectral response accelerations.


thanking you verymuch
BR
Tharani