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Are there any CA structural engineers on this forum?

  1. Nov 10, 2005 #1
    Need help with interpreting the UBC!:surprised :biggrin:
  2. jcsd
  3. Nov 10, 2005 #2


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    What part?
  4. Nov 14, 2005 #3
    The part of the special seismic load combo with 1.2DL+0.5LL+Em.
    When I use this equation, do I apply a 1.33 increase if I choose to stay in
    ASD, or do I have to multiply Em by 1.4 (to bring to strength level) and then apply a 1.7 increase.

    My boss told me that Em is in strength level already and that a 1.7 increase is applicable.

    Any suggestions?

    Thanks, :biggrin:
  5. Nov 15, 2005 #4


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    Figured it was gonna be seismic. At which point I can't help you. You might try the local building dept. --- if they're competent. Local building codes probably include very specific local amendments, and rules for application --- wouldn't surprise me, nor would it surprise me if CA has a blanket amendment incorporating "design factors to be determined from whatever counts as the latest study of damages from previous quakes."
  6. Nov 15, 2005 #5
    Thanks for the attempt. :biggrin:

  7. Dec 29, 2005 #6
    I am sure you have it figured out by now, but that whole equation (including Em) is strength level equation. So for ASD, you would divide the Em part by 1.4 and then get to use a 1/3 stress increase if you choose (latest Codes have taken out the 1/3 increase). It is easiest to just start with the service level equations if you are using ASD: D+L+Em/1.4..... etc.

    Be sure not to mix and match factors between service and strength design.
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