seismic load on tank

huangyhg

seismic load on tank
hi,
i have a cylindrical tank (oriented horizontally on integral stands). i am trying to calculate the horizontal force imparted by the tank during a seismic event. normally we only deal with buildings. should i proceed with the same type of calculation as what we would do for a building or is there some quicker method that can be used? i am working in ontario using our codes.
normally we use the simplified method (v=vsifw) type of equation. i'm  not sure how to calculate the period etc.. for the tank supports.
any help would be greatly appreciated.
r.querin, p.eng.
i have found in the web this answer to related question:
for horizontal vessel, the consideration on the support is cantilever with concentrated load at top.
approximately we calculate period t (seconds) = 0.32sqrt(d)
where d=pl^3/3ei (deflection in inches)
p= vertical load (kips)
e= modulus of elasticity (ksi)
i= moment of inertia (in^4)
l= height of cantilever (in)
hope this help