Wooden planks 300 mm wide by 100 mm thick are used to retain soil with height 3 m. The planks used can be assumed fixed at the base. The active soil exerts pressure that varies linearly from 0 kPa at the top to 14.5 kPa at the fixed base of the wall. Consider 1-meter length and use modulus of elasticity of wood as 8.5 x 10^3 MPa. Determine the maximum bending (MPa) stress in the cantilevered wood planks.

For a simply supported prestressed concrete beam, compute the stress in the top fiber at the centerline. Properties of the beam are: Width of the beam, b: 222 mm; Depth of the beam, d: 396 mm; Eccentricity of the beam, e: 177 mm; Prestressing Force, P: 541 KN; Superimposed Load, w: 8 KN/m; Length of the beam, L: 11 m. Stress is in unit MPa. Write only the value of your final answer. w (including selfweight) 000