seismic design per asce 7-05

huangyhg

seismic design per asce 7-05
in the seismic requirements for boilers and pressure vessels in chapter 15.7.11 of asce 7-05:
a)applying 15.7.2(c)(1) for cases considering vertical seismic effects, results in an equation for static head as
sh = gammal*(0.2*sds*i+1)*depth.  is this correct?  when loading combinations require the seismic acceleration to be up, this equation stays the same, correct?
b)in applying 15.7.11.5 are you supposed to use equations from 15.7.6.1?  if so, is wc = deltas*cross section area*specific weight?  is the specific weight used in this equation, gamma l or gamma l as altered by 15.7.2(c)(1).
c) can someone explain why if a is applied by adding it to the design pressure for each compoenent, that 15.7.2(c)(2) must be applied as well?
thank you in advance.