Size effect

This paper surveys the available results on the size effect on the nominal strength of structures - a fundamental problem of considerable importance t o concrete structures, geotechnical structures, geomechanics, arctic ice en gineering, composite materials, etc., with applications ranging from struct ural engineering to the design of ships and aircraft. The history of the id eas on the size effect is briefly outlined and recent research directions a re emphasized. First. the classical statistical theory of size effect due t o randomness of strength, completed by Weibull, is reviewed and its limitat ions pointed out. Subsequently, the energetic size effect, caused by stress redistributions due to large fractures, is discussed. Attention is then fo cused on the bridging between the theory of plasticity, which implies no si ze effect and is applicable for quasibrittle materials only on a sufficient ly small scale, and the theory of linear elastic fracture mechanics, which exhibits the strongest possible deterministic size effect and is applicable for these materials on sufficiently large scales. The main ideas of the re cently developed theory for the size effect in the bridging range are sketc hed. Only selected references to the vast amount of work that has recently been appearing in the literature are given. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.