Problem 3.1: Determine the base width of a 20-m high trapezoidal concrete gravity dam having a vertical upstream face and a top width of 5 m (see Figure 3.53). Design water depth is 18 m. There is no tail water. Ignore earthquake, silt, and ice loads. Take e-B/6 (EV is at the toe side with respect to the centerline of the base) o 30 MPa, Of =80 MPa, t-6 MPa, and o=-1.0. Specific weights of water and concrete are 10 kN/m and 24 kN/m, respectively. Answer: B=11.82 m. 18 m NK 20 m 5 m B=? Figure 3.53 Cross-section of dam for Problem 3.1.