huangyhg

asce 7-05 increasing factors (overstrength, redundancy)
i have been going through the asce 7-05 as i am starting to get into higher seismic areas. i think i have a grasp as to when the redundancy factor would be greater than 1.0 however i am somewhat confused as to when the overstrangth factor comes into play. i know that you would apply the overstrength factor to say a collector or that you would apply a 1.4 increase for elements of the wall anchorage system per 12.11.2.2.2, however im unsure as to when else i would apply the overstrength factor that is given in table 12.2-1. can anyone shine some light on the issue or any other increasing factor that i have not mentioned.
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battered piles
the overstrength factor is used, as you say, with collectors. also brace connections and diaphragms. basically the intent is to ensure that rigid, brittle connections don't control the failure - that brace
jae,
i didnt see anywhere that the overstength factor would apply to the diaphragm. when you say diaphragm are you referring to the attachment of the diaphragm to the steel supports?
12.11.2.2. requires the load to be increased by 1.4 for cat. c-f
the diaphragm requirement is rather cryptic (and might be argued both ways) but i found the reference through the aisc seismic requirements.
i've attached a memo that we used on another project and it is for a specific situation - but the logic flow might help you see why diaphragms could be considered as part of the seismic force resisting system:

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