Question:
In a combined structure made of members and surfaces, I have a frame with beams that have member hinges. The moment diagram of the beams looks strange.
What is the reason?
Answer:
If the beam and the surface are in the same plane, they are firmly connected to each other.
Although the member end has a member hinge, it is already connected rigidly to the surface in the next FE element and shares the load transfer with the surface by means of bending. To avoid restraining moments, the surface must also have a line hinge.