A plain concrete wall (i.e., a wall with no steel reinforcement) rests on a secure foundation and serves as a small dam on a creek (see figure). The height of the wall is h = 6.0ft and the thickness of the wall is t = 1.0ft.
(a) Determine the maximum tensile and compressive stresses σt and σc, respectively, at the base of the wall when the water level reaches the top (d = h). Assume plain concrete has weight density γc = 145 lb/ft3.
(b) Determine the maximum permissible depth dmax of the water if there is to be no tension in the concrete.