| Steel reinforced concrete (SRC) special-shaped column structure is a new structuralsystem, which is the combination of special-shaped column structure and SRC structure.It not only makes better use of available space and improves the esthetic appearance ofstructure, but also has high strength and good seismic performance. The basic mechanicalbehavior and seismic performance of SRC special-shaped column and beam-column jointhave been studied. Based on the previous studies, the research on seismic performanceand design method of SRC frame with special-shaped columns is systematicallyperformed in this dissertation.According to the experimental study on3models of two-bay and three-story framecomposed of reinforced concrete beams and SRC special-shaped columns under lowcyclic reversed loading, the failure process and pattern were observed. The straindistribution of shaped steel, load-displacement hysteretic loops and skeleton curves wereobtained. The mechanical behaviors such as load bearing capacity, inter-story drift ratio,ductile, energy dissipation and stiffness degradation were analyzed. The results show thatthe SRC frame with special-shaped columns is a typical strong column and weak beamstructure, and can form the beam-hinged failure mechanism. The hysteretic loops aresymmetric and plump. Compared with the reinforced concrete frame with special-shapedcolumns, the ductile and energy dissipation are better. Based on the experimental results,the restoring force model of SRC frame with special-shaped columns is presented.The static elasto-plastic analysis on SRC frame with special-shaped columns under monotonic loading was carried out by using Abaqus. The calculated results agree wellwith experimental results. According to the calculated results, the mechanicalmechanisms of SRC frame with special-shaped columns are analyzed, obtaining the lawof stress distribution and development of section and failure modes. Furthermore,parametric analysis of mechanical behavior of SRC frames with special-shaped columnswas performed. The concrete strength, steel strength, axial compression ratio, ratio ofspecial-shaped column limb height to thickness, stiffness ratio of beam to column andyield bending moment of beam to column were all considered as analysis parameters.The hysteretic performance analysis and dynamic analysis on SRC frame withspecial-shaped columns were carried out by using Opensees. The finite elementcalculation of experimental specimens under cyclic loading is finished, of which theresults agree well with experimental results. According to the calculated results, themoment-curvature hysteretic loops of beam ends and column ends are given, and theinfluences of P-Δ effect and axial compression ratio are analyzed. The modal analysis andtime history analysis were performed on the experimental frames. Verified by Sap2000,the analysis models are proper. Based on the calculated results, the dynamic responses ofdisplacement, acceleration and base shear under the different earthquake waves with thesame maximum acceleration and the same earthquake wave with different maximumaccelerations are analyzed.Referring the current codes, five performance levels are put forward for SRC framewith special-shaped columns, which are full operation, temporary operation, reparableoperation, life safety and collapse prevention. The five performance levels and threeseismic levels are combined to form the seismic performance target. Based on the resultsof seismic performance tests on SRC special-shaped columns and frames, the maximuminter-story drift angle corresponding to different performance levels are presented for theSRC frame with special-shaped columns.Performance-based seismic design theory is applied to the SRC frame withspecial-shaped columns. Against the structural characteristic, the design procedure isgiven, and taking eight-story frame as an example, the design process is demonstrated.Besides, the design methods of member section of SRC frames with special-shapedcolumns are proposed by generalization and analysis. |
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