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'97 UBC Element Design

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>From: Chris Palmateer <chrisp(--nospam--at)>
>To: seaint(--nospam--at)
>Subject: '97 UBC Element Design
>I was hoping that someone could help shed some light on how to do element 
>design using the '97 UBC.  Specifically, I'm looking at designing tall 
>slender concrete and masonry walls.
>Assuming zone 3 and soil type Sd for a solid grouted masonry wall, equation 
>(32-2) yields 0.48 Wp (ultimate load).  When substituting into the basic 
>load combinations listed in 1612.2.1 (strength design), equations (12-5) & 
>(12-6) contain the variable E, where E = (rho* Eh) + Ev.  Eh is defined as 
>"the earthquake load due to base shear, V, as set forth in Section 1630.2 or 
>the design lateral force, Fp, as set forth in Section 1632".  E is now equal 
>to 1.0(0.48 Wp) + 0.18 Wp = 0.66 Wp!

Note that the Ev term is a Vertical load, "equal to an addition ... to the
dead load effect...", not a horizontal force. Thus, assuming your other
calculations are correct, you would design for a horizontal earthquake
force of 0.48Wp, and a factored Dead Load of (1.2 + 0.18)DL or (0.9 - 0.18)DL.

Allen Adams