Research On Moment-curvature Hysteretic Relationship Of Steel Reinforced Concrete

Steel Reinforced Concrete (SRC) structures have advantages over reinforced concrete (RC) structures in strength and ultimate deflection capacity. moment—curvature ( M ~ Φ ) relationship and restoring force models are the basis of computing member's force—displacement ( P — Δ ) hysteretic curves and analysis of dynamic structure response under earthquake. Numerical calculation of M ~ Φ hysteretic curves has theoretical and realistic significance for hysteretic properties, ductility and energy dissipation of SRC structures.Based on strain-stress hysteretic models of concrete and shaped steel, a numerical method is applied to calculate SRC skeleton curves and hysteretic curves of hollow-web sections and solid-web sections, with concrete compressive strength, steel yielding strength, axially compressive load and shaped steel areas as factors. Methods of calculating M ~ Φ and P - Δ restoring force models according to test results are introduced. At last, using bilinear and trilinear M ~ Φ restoring force models, seismic response of 3—story and 3—span composite frame is analyzed subjected to different peak acceleration and earthquake waves, respectively. Vibration modes, displacement time history of top story, collapse mechanics and damage index are also discussed.Through analyzing lots of computing results combined with test data and taking influence of concrete strength, steel yielding strength, axial compression ratio and shaped steel reinforcement ratio into consideration, skeleton curves, hysteretic loops, initial rigidity, ultimate moment, strength and stiffness degradation laws after yield excursion are discussed, respectively. Comparing seismic response relative to bilinear model with the trilinear model's, reasons for different results are analyzed, then reasonable recommendations for choosing restoring force models are presented.