When viewed from downstream, Hoover Dam in the US is roughly trapezoidal (see www.usbr.gov/dataweb/dams/nv10122.htm), as in Fig. P4.4. The width at the top is W_H = 1244 ft; the width at the bottom is about 2⁄3 of that, or W₀ = 830 ft; and the height of the reservoir, assumed here to reach almost to the top, is H = 576 ft. The dam contains 4,400,000 cubic yards of concrete, which has a specific gravity of 2.4.

(a) Derive an expression for the net pressure force acting horizontally on the dam. With coordinates as in Fig. P4.4, that is F_Px.

(b) How does the horizontal force (in N) compare with the weight of the concrete?

Transcribed Image Text:

Face View WH Dam ZA Wo Figure P4.4 Hoover Dam (not to scale). Water H Side View ZA X Air P= Po