SizeEffectsQuasibrittleFracture:ApercuofRecentResults

The paper consists of two parts. In view of length limitations, and because several comprehensive reviews behind the present lecture were already published in journals, the first part is limited to listing various recent advances that a.re surveyed in the conference lecture. The second, much er, pa.rt then complements this survey by presenting in mathematical terms several new results that long are only outlined in the lecture. These results concern: 1) a derivation of the first two terms of the small-size asymptotic expansion of size effect of the cohesive crack model; 2) a review of the derivati on of the first two terms of the large-size asymptotic expansion of size effect ensuing from the smeared -tip method; and 3) a. size effect formula for a very broad size range, unifying the fracture energies measured by the size effect method and the work-of-fracture method. 1. OVERVIBW OF SOME RECENT RESULTS • size effect in redundant beam struct ures failing The size efiect represents the most important by softening inelastic hinges; and practical consequence of fracture behavior as well • size effe<:t hidden in excessive dead load fac- as the clue to uncovering various fundamental char- tor in the design code:; (Bafant and Frangopol acteristi cs of concrete fracture . Interest in the qua- 2000). sihri tt.le size effect, which started in the 1970s and surged throughout the 1990s, continues unabated In the closing of the lecture, it is pointed out that. and will probably persist for some time because the size effect must have played a major, yet. previ- significant open questions remain and applications ously unrecognized, role in a host of famous struc- in design, especially in terms of revisions of design tural catastroph es (e.g., Malpasset Dam, St. Fran- code specifications, are still deplora bly limited.