In a wall-slab deep underground station, the slabs have holes for escalators and vent shafts. The holes are arranged adjacent to one of the walls. Therefore, strong beams surrounding the holes are required to support the wall from bending inward. These beams surrounding the hole also prevent the slab from swelling towards the hole.

If the slabs (and hence the beams) are in X-Y plane, the moment (induced by the horizontal soil and water pressure on the walls) causing the beams to bend towards the hole is M22 (of the beam element). However, this figure does not equal to the twisting moment of the shell element which are connected to beam.

The question is: Which SAP's shell elemet output is the resultant moment causing the shell element to swell towards the hole, M11, M22 or M12?

My understanding of shell elements' resultants are as follows:
M11 and M22 cause the shell to bend upward or downward, i.e. out of plane bending ;
M12 twists the shell and hence causes the shell to bend towards the hole

But M12 of a shell are not equal to M22 of a beam!!! Please help!!!