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I think both ETABS and UBC 97 provisions are correct. As ETABS completely follows UBC97 therefore only UBC's provisions are elaborated below. UBC seismic design philosophy limits the minimum time period (in the form of maximum base shear ) to Ts (UBC response spectrum) which is equivalent to Cv/2.5Ca. For elaboration , V=CV.I.W/R.T Substitutue T=Ts=Cv/2.5Ca in above eqn therefore V=(CV.I.W/R)X(2.5Ca/Cv) i.e V=2.5Ca.I/w (the maximum base shear that ETABS and UBC97 uses) Therefore time period regardless of its shorter value below Ta cannot be lesser than Ts which is in contrast with UBC97 provisions that are inherent in ETABS. However, analysis indicating time period lesser than Ta indicates a over stiff/over design structure, therefore it is recommended to maintain a natural period closer to 0.1x (no of floors).

In calculating design forces, have you considered the application of point load on a panel, which will support lights, at the top of the pole, in addition to the UDL on the pole itself. Is it possible that only two bolts will be effective in resisting moment for a wind direction in which two bolts will lie on the neutral axis, and the moment arm will be sqrt(2) x 12.

My initial post was to point to fellow engineers that one must look at the value of the time period used by the ETABS for calculating the base shear. For normal construction in Pakistan, the construction in which the area of shear walls seldom exceeds 1% of the floor area, the time period of the building should not be significantly less than the value obtained by empirical formulae of UBC 97. If ETABS is using the value which is, say 60%, of that value, then there should be some mistake in modeling, and the design engineer should be aware of that.