Non Deterministic Approaches

 The manner in which an engineering structure will respond to loading depends on the type and magnitude of the applied load and the structural strength and stiffness. Whether the response is considereded satisfactory depends on the requirements which must be satisfied.

 These include safety of the structure against collaps, limitations on damage, or on deflections or other criteria. Each of these kind of requirement may be termed a limit state. The 'violation' of a limit state can then be defined as the attainment of an underirable condition for the structure.

 The study of structural reliability is concerned with the calculation and prediction of the probability of limit state violation for an engineered structural system at any stage during its life. In particular, the study of structural safety is concerned with the violation of the ultimate or safety limit states for the structure.