Overland Conveyor ASCE 7-05 1

[DijonEIT]

I am in the middle of determining seismic loading for the design of overland conveyor bent foundations. We have chosen to identify the structure as an inverted pendulum. In 15.4, I see that the fundamental period (T) of the structure cannot be calculated per the usual 12.8-7, 12.8-8, 12.8-9 according to 15.4.4.

The equation given in 15.4.4 is confusing to me, I'm not sure where to come up with the "fi" and "delta i" values, can anyone explain these?

 

[structSU10]

the fi is the applied load at level i, and the deltai is the corresponding lateral deformation at level i. From my understanding, the force can be arbitrary to determine the deflections to input into the equation. This can be verified by any FEA program capable of doing general dynamic analysis (RAM, SAP, etc.)

 

[DijonEIT]

Thanks structSU10, it makes sense now to consider that the force would be arbitrary because the structure's stiffness will remain the same regardless of the fi that I used.

Thanks!