Problem #4-If the load in the middle of a plain concrete beam is P=10KN, design the beam height if the thickness of beam is 0.15 m. Consider tensile strength ft=5.0 MPa and S.F. = 3. (20 pts.). (Hint: Use the method of Strength of Materials: stress < strength/SF) ? 1 m P= 10KN 15 cm