Seismic response

[fenderbassman]

I am currently designing a 4-story wood-frame condo bldg. on a post-tension slab above a ground-level garage.

I am accustomed to determining Cs per ASCE7-02 9.5.5.2.1. A maximum, a minimum and also a value between the max and min are determined for Cs.

My question is: My reading of the text implies the minimum value of Cs may be used in determining V, the seismic base shear.

Is this a correct reading?Is there a min Cs of 0.01 in later editions of ASCE7?
Thanks,
Dave in Denver

 

[structSU10]

The section just sets and upper and lower bound for Cs. You calculate it using Cs = SDS/(R/I) (Eq 9.5.5.2.1-1).

If that value is greater than SD1/T*(R/I) (Eq 9.5.5.2.1-2), you use the value for SD1/T*(R/I). If SDS/(R/I) is smaller than 0.044*SDS*I (Eq 9.5.5.2.1-3), you use the value of 0.044*SDS*I.

If the value of SDS/(R/I) falls between those bounds, then you use that value for design.

 

[MrHershey]

Minimum of 0.01 replaced 0.044*Sds*I in ASCE 7-05 I think.

Then the 0.044*Sds*I that structSU10 references was added back in through supplement no. 2.

Supplement No. 2 to ASCE7-05 (PDF)