huangyhg

moment connection revisited
i would like to elaborate and continue this discussion on moment connection.
thanks for the info you helped me alot.
ok a moment connection transfers the moment from one section to the connected section. this is common with a beam to a column and a beam to a beam in line. but what if the connection of a beam to a beam is perpendicular. is the moment transferred to the other beam; that beam is supported at both ends. do i apply the moment calculated for the cantilever section over to the perpendicular beam supported at both ends? or is there a modified calculation?
it depends on the beams and the connection. again is a matter of structural analysis and proper understanding of the beams and connections. as a load, will induce deflection, shear and flexure in the supporting beam. if the supporting beam is strong against torsion such a tube it will take torsion even from one non torsion transmitting connection out of eccentricity of the reaction.
vintage70,
if i'm following your description correctly (here's where a pen and a napkin would really come in handy), the moment at the end of the cantilevered beam would have to be carried by torsion into the beam it's framing into. if the cantilevered beam were centered on the other beam and end conditions of the other beam were the same (note, the supports would also have to carry this torque) then half the moment would go one way as torque and the other half the other way.
btw, you said "beam" so i immediately think of wide flanges. depending on the size of beams and the load you may (probably will) find that deflections are excessive.
if i think this correctly, then i think i agree with rkillian.
if you have a beam (a) that is rigidly connected to another beam (b) at a 90 degree angle, then beam b sees a torque from a, which cannot be treated as a bending moment in beam b.

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