Page - 1127 - in Book of Full Papers - Symposium Hydro Engineering

Fig. 1 Life Cycle Management of Levees (according to [1]) 2. DEFINITION AND PROCESS CLASSIFICATION An accurate, general valid definition for the term “ageing” for engineering structures, especially embankments dams, is hard to find in literature. Some authors provide definitions for special applications [2] [4] [5]. The term “ageing” defines the time-dependent alteration of characteristics of structures or materials. In this context the deterioration of characteristics is usually analyzed which leads to a deterioration of the structural behaviour in terms of stability, serviceability, and durability. In contraction to this general approach ageing processes may also lead to an improvement of material characteristics and structural behaviour as discussed in [3], such as the hardening of concrete sealings/barriers and the clogging of cracks in sealings. A definition is given in the ICOLD bulletin No. 93: “For the purposes of this therefore, ageing is defined as a class of deterioration associated with time- related changes in the properties of the materials of which the structure and its foundation is constructed. Excluded are the effects if exceptional events. Under 1127