please refer to attached diagram from his workbook key.
in his lecture video, he explains that we should look at these as bays of rigid frame. so there are 2 bays in this diagram.
what i don't get is, why is the middle B does not share some of the tie-down with C?
ie., C takes all the tie-down, A does all the push-up, B does nothing for vertical load, but when all A, B and C help with the over turning moment?
hope someone can help.....
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i think i may have an answer to this:
is it because A and C work as a Couple (due to OTM) with B being the centre of the couple and therefore, B is zero?