We want to design a reinforced concrete beam that overhangs the supports on both ends. To design that beam, we need to know the design moments, both positive and negative, at midspan (point B)....

We want to design a reinforced concrete beam that overhangs the supports on both ends. To design that beam, we need to know the design moments, both positive and negative, at midspan (point B). Remember that live load can act everywhere, somewhere, or nowhere.