Dreaming that the beam is broken indicates that the structure is unstable, which may imply that the dreamer's foundation is shaken, squeezed unsteadily, or his belief is shaken, or he has lost some support and strength.
Former Duke of Zhou:
I dreamed that the shed beam was generating electricity, so I avoided it at home. Dunhuang dream book
The sudden fracture of the roof beam is the culprit. Duke Zhou