Use kinematic method
(a) Use simple plastic theory and an upper bound approach to find the collapse mechanism and collapse load for the frame shown. Note that the ends of the beams have been reinforced to 3My over a distance L/20, as shown in the figure. Express the answer in terms of M and L.
(b) Show that the solution leads to a statically admissible moment distribution:
20 (typ.)
3Mp (typ.)
Mp
2Mp