Specifying Transient Analyisis Direction

BRYGN · Post by **BRYGN** » Thu Mar 17, 2005 5:37 am

I was wondering if there is any way to apply a ground motion to a structure in a direction other than one of the three principal axes.

Thanks

BRYGN

Post by **fmk** » Thu Mar 17, 2005 10:34 am

no .. but you can always orientate your structure to be off the grid .. same result.

Post by **fmk** » Thu Mar 17, 2005 12:03 pm

or you could always write a tcl proc which would break the motion up into it's components!

lish hit · Post by **lish hit** » Sat Mar 19, 2005 10:01 pm

Build you model not in principal axes,input groud motion in principal axes.

BRYGN · Post by **BRYGN** » Mon Mar 21, 2005 4:33 am

Thanks! These are both ideas that I had crossed my mind but I am lacking knowledge on how to implement. As far as building the model off the principal axes goes, that seems doable if you have one or two directions you want to use for the excitation. I am wanting to consider many different directions and therefore see this approach as somewhat laborious and awkward.

My preference would be to break the ground motion up into its components but I don't know if it is possible to run two orthogonal ground motions simultaneously. Are there any pointers?

Thanks