Page 82 - Handbook of Civil Engineering Calculations, Second Edition

STATICS, STRESS AND STRAIN, AND FLEXURAL ANALYSIS 1.65

FIGURE 45. Moment distribution.

4. Apply balancing moments; distribute them in proportion to the
stiffness of the adjoining spans
Apply the balancing moments at B and C, and distribute them to the two adjoining spans
in proportion to their stiffness. Thus M BA 6.0(15/31) 2.9 ft·kips ( 3.93 kN·m);
M BC 6.0(16/31) 3.1 ft·kips ( 4.20 kN·m); M CB 30.8(16/25) 19.7 ft·kips
(26.71 kN m); M CD 30.8(9/25) 11.1 ft·kips (15.05 kN·m).
5. Perform the “carry-over” operation for each span
To do this, take one-half the distributed moment applied at one end of the span, and add
this to the moment at the far end if that end is considered to be fixed during moment
distribution.