empty condition. To alleviate this it may be necessary to introduce an
upstream prop, as indicated on the figure, or to modify the central angle
2 . The profile is best suited to narrow and relatively symmetrical steep-
sided V-shaped valleys.
(c) Cupola profile
In its developed form the double-curvature cupola has a particularly
complex geometry and profile, with constantly varying horizontal and ver-
tical radii to either face. An example of the type demonstrating the geo-
metrical complexity is shown in Fig. 3.15. A trial geometry suitable for
preliminary design purposes can be selected using the nomograms
160 CONCRETE DAM ENGINEERING
Fig. 3.14 Arch dam geometries and profiles
