How to apply groundmotion in an arbitary direction?

[mkfotouhi]

Hi
I want to model the effect of earthquake inceedent angle to structures. So I need to apply the earthquake records in different angles to the structures. but in the opensees there are only three main direction available(1,2,3 =x,y,z). What shoud I do to model an structure which affected by an eathquake make a 30 degree angle whith the x axis?
thanks alot

[fmk]

either break into into components .. or rotate the structure the 30 degrees .. remember with the coord transformation you can rotate the col axis (they dont have to be orientated in x, y, z)

[mkfotouhi]

tnx fmk
but I need to repeet my analysis many times whith one structure but many earthquake angles(5, 10, 15, ..,90 degree) and if i want to change the whole structure each time I need to make many models. Also because I need nonlinear analysis, I can not use superposition ruls and can not break the record to its components.
Is not there any other way for me to introduce the angle of earthquake incident other than x,y,z?
waiting for your guidance.

[fmk]

no, all i could do would be to decompose it as well .. forces in the inside of any fe program must be provided in the dof directions (if another fe package takes it at an angle they must decompose it internally) .. for your problem just write a single tcl proc which takes as i/p the angle and then generates the model rotated.

[mkfotouhi]

thanks alot fmk for your kind attentation.
Hope to learn more from you later.