Theorem of three moments
In civil engineering and structural analysis Clapeyron's theorem of three moments (by Émile Clapeyron) is a relationship among the bending moments at three consecutive supports of a horizontal beam. Let A,B,C-D be the three consecutive points of support, and denote by- l the length of AB and l ′ {\displaystyle l'} the length of BC, by w and w ′ {\displaystyle w'} the weight per unit of length in these segments.