If a beam's y-y axis lies in the plane of the paper, do I use Ixx or Iyy from sections table?
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If the tables have units of length to the 4th power, I think you are referring to the second moment of area, rather than the moment of inertia. Over the past 50 years, the x y and z axes associated with the longitudinal and cross sections of a beam have been variously defined by different codes, tables, text books and countries. You have to be clear in each case what you mean. What people mean by 'the usual configuration' can be very different in another context.
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