Uplift on Cladding due to Seismic Forces

[PrecastJoe3]

As we know, for cladding design there is a fastener force factor involved in the design of non-ductile elements. The reasoning I believe is to ensure that the non-ductile elements perform under 3 times a higher seismic load, than the design load.. where as it is not used for ductile elements because they can yield and dissipate the energy.

My question has to do with uplift forces. A connection that does not see an uplift force in the body level, but sees uplift force in the fastener level. For this situation..

a. Should the connection be designed for uplift fastener forces even though it doesn't see uplift in the body level?

 

[PrecastJoe3]

b. what is the concept of fastener forces for components? Is it to "over-design" non-ductile elements for the given seismic load? or is it saying that there is a chance that the seismic load will be as high as 3 times more than the design seismic load.. and hence design your weaker non-ductile elements for this higher load?

 

[PrecastJoe3]

bump.

 

[PrecastJoe3]

i answered my own question.. ASCE 7-05 clearly says that fastener forces should be applied to the C.G of the panel.. meaning you WILL see uplift forces in fastener level.. and the fastener portion of the connections will have to be designed for it..