Chapter 3
Concrete dam
engineering
3.1 Loading: concepts and criteria
3.1.1 Loads
The principal loads operative upon dams were identified in Section 1.7.2
and illustrated schematically in Fig. 1.8. The purpose of this section is to
define the magnitude and mode of application of major loads in relation to
the analysis of concrete dams. Where appropriate, the character of certain
loads is discussed in greater depth.
This chapter assumes an understanding of fundamental principles of
hydrostatics and structural theory. The equations quantifying loads and
defining structural response are introduced without detailed derivation or
proof; reference should be made to appropriate undergraduate texts, e.g.
Featherstone and Nalluri (1995) and Case, Chilver and Ross (1993), where
derivations are desired.
The transverse section of a concrete gravity dam is illustrated in Fig.
3.1; base plane X–X lies at a depth z 1 below reservoir water level. The
expressions detailed in subsequent paragraphs define the pressures and
resultant forces applicable to the section above X–X and all similar hori-
zontal planes through the dam. For convenience in analysis loads are
expressed per metre length of dam, i.e. they are determined for a two-
dimensional transverse section with unit width parallel to the dam axis. It
is similarly convenient to account for some loads in terms of resolved hori-
zontal and vertical components, identified by the use of appropriate sub-
scripts,PhandPvrespectively.