INT 9531299 Bazant This U.S.-Czech research project between Zdenek Bazant of Northwestern University and three researchers from Czech Technical University, Zdenek Bittnar, Milan Jirasek and Jan Vitek, will focus on inelastic hinges in frames of buildings and bridges that undergo progressive damage and exhibit softening resulting from dynamic or cyclic loading such as that caused by earthquake, blast or impact. Such damage can remain distributed over many inelastic hinges or it can localize in only some of them. Dr. Bazant and his Czech partners note that localization is a dangerous phenomenon because it can cause collapse to occur more rapidly. This project will involve a systematic, theoretical and numerical study of the localization problem. The progressive degradation and fracture of concrete in compression under lateral confinement simulating the effect of reinforcement will also be studied, with analysis of localization and fracture extended to the shear failure of beams. Particular attention will be devoted to the size effect brought about by localization of softening and by fractures in tension, shear and compression. Results are expected to help make predictions of concrete structures' resistance to dynamic and cyclic loading more realistic and subsequently contribute to safer designs. This project in mechanics and materials engineering fulfills the program objective of advancing scientific knowledge by enabling experts in the United States and Eastern Europe to combine complementary talents and share research resources in areas of strong mutual interest and competence. ??
