The designer can calculate the approximate period Ta from the formula 12.8-7 which is;
Ta = Ct (hnx) (EQ 12.8-7)
Or he or she can use an approximate period from section 11.6(1) equal to 0.8(Ts ) where Ts = SD1/SDS.
My question is if you compare both methods to calculate Ta would you use the maximum or minimum results for Ta when calculating the Seismic Response Coefficient Cs in formula’s 12.8-3 and 12.8-4?
Dennis S. Wish, PE
Dennis S. Wish, PE
California Professional Engineer
Structural Engineering Consultant
dennis.wish@verizon.net
http://structuralist.wordpress.com
http://www.structuralist.net