Moment Distribution Method - Theory (Part -2)

Second principle we need to know is

• Carry over factor

Let us see the ideolized free body diagram of single beam.

Moment required to give rotation q_A  is M_A . we can write this

Therefore

From these two equations we know that  M_B = 1/2 M_A.

And we can say that 1/2 of the moment from pinned end is carried over to the fixed end. Note that this is positive here because of same directional rotation.

• Fixed End Moments 

Fixed end moments of the elements will be needed to proceed the moment distribution method. The formulae are presented in the appendix part of structural analysis books.