NUMERICAL STUDIES OF MOMENT-ROTATION BEHAVIOR IN STEEL AND COMPOSITE STEEL-CONCRETE BRIDGE GIRDERS

Presented in this paper are the results from several finite element studies of the inelastic moment-rotation behavior of continuous-span noncompact bridge girders at interior-pier locations. Specifically, four component tests, which have been conducted experimentally in previous research supported by the American Iron and Steel Institute, are performed numerically in the present work. Three of the test specimens are all-steel girders and one is a composite design. All of the specimens were designed with ultracompact flanges and with closely spaced transverse stiffeners in the peak negative moment region. The web slendernesses vary from being nearly compact to the extreme range allowed for design of transversely stiffened girders. The analysis results for these tests are compared with the experimental responses, and aspects of the behavior elucidated by the finite element predictions are discussed. These studies confirm that continuous-span noncompact bridge girders can exhibit a significant and reliable capacity for inelastic rotation at interior supports.