Performance Characterization of Beams with High-Strength Reinforcement

Performance Characterization of Beams with High-Strength Reinforcement

The proposed study will explore critical material and structural behaviors at the boundaries of high-strength steel properties that can currently be achieved. Key steel properties that will be explored are: 1) the tensile-to-yield strength ratio (T/Y ratio), 2) the ultimate or uniform elongation, su, and 3) the low-cycle fatigue performance relevant to seismic applications. Material and structural tests on concrete columns are proposed to be conducted by Wassim Ghannoum, University of Texas, Austin, and are not funded as part of this proposal. This proposal (UC Berkeley) is to conduct tests of beams, and to determine how beam rotation capacity is affected by material properties. The tests will provide much needed experimental evidence to define structurally acceptable properties for steel mills to target in production and the research community to use in structural testing. In addition, this proposal will also carry out limited analytical studies of archetype buildings to establish seismic demands for beams and columns; and additional analytical studies to develop models for plastic-rotation capacity of beams and to extract implications for non-seismic designs.