Hi I'm a civil engineering student, I wanted to ask for help and clarification for the design of mat footing. I used the Rigid method and based my design on the ACI 336_2R and Foundation Engineering by Braja M. Das. I have an issue with the moment diagram. Though, the shear force diagram my add up to zero, but the Bending Moment diagram doesn't. I tried back tracking my work yet I can't find a solution for it. Your help and opinions is greatly appreciated.enter image description here