UPLIFT PRESSURE IN GRAVITY DAMS

Abstract

The present,. dissertation reviews the historic and recent developments in the idea of uplift in gravity darns. Though uplift is. the second major adverse force on a gravity surprisingly it was not even being taken into account upto nearly the end of the last century. Confusion regarding its intensity and area persisted upto fairly recent time. It is only now that theory, experiments and field observations have more or less led to uniform assumption. Theoretical work has been reviewed in Chapter II, while experimental work has been .discussed in Chapter III. Observations and actual cases have been described in Chapter IV. The authors comments on the previously described_ work are given in Chapter V, while the conclusions are summarised in Chapter VI. It has been shown that though the area factor varies within narrow limits depending on the nature of the material, an assumption of unity area factor is justified for design purposes. It is independent of permeability and stress, and is greater than the porosity of the material, presumably due to the micros tructural 'characteristics of concrete. The measured, intensities in most cases are almost below the usual design assumptions. The space frame concept put forward in some recent work is not yet usable in designing.