MODELING OF ASSESSMENT OF SEISMIC PERFORMANCE OF COMPOSITE FRAMES WITH REINFORCED CONCRETE COLUMNS AND STEEL BEAMS by Sameh Samir Mehanny and Gregory G. Deierlein

Composite moment frames consisting of steel beams and reinforced concrete columns (so called RCS moment frames) are one of several types of hybrid systems gaining acceptance as cost-effective altematives to traditional steel or reinforced concrete frames for seismic design. New design standards for composite moment frames have recently been introduced in the United States, and composite RCS frames have been one focus area investigated as part of Phase 5 (Composite and Hybrid Structures) of the US-Japan Cooperative Earthquake Research Program. This research presents an extensive and pioneering analytical study whose focus is on the seismic behavior of composite frames with the objectives to (1) develop and improve existing analytical models and techniques for the nonlinear inelastic static and time history analyses of composite RCS moment frames, (2) propose damage indices and performance criteria to assess seismic performance of such frames, (3) apply accurate nonlinear analysis methods to evaluate building performance under varying seismic hazards, (4) develop and correlate stability limit states to performance levels suggested by modern seismic codes, and (5) investigate response dependency on ground motion parameters so as to reduce the uncertainty in estimating median response. The ultimate goal is to achieve broader acceptance of RCS frames in high seismic regions by demonstrating their reliability through a modem performance-based methodology.