Experimental And Theoretical Study On The Seismic Performance Of RC Frames With Specially Shaped Columns

For the purposes of practical application of RC frames with specially shaped columns in high intensity earthquake fortification areas and accumulation of experimental and theoretical data for the technical specification of RC frames with specially shaped columns, the seismic performances of these frames were studied through experiment and theoretical analysis. The detailed work of this research project is stated as follows:1. Pseudo-static tests of three two-bay and three-story frame specimens for studying their seismic performance were designed and conducted, which were designed according to the anti-seismic requirement of the earthquake fortification intensity 8. Experimental research included the hysteretic behaviors, skeleton curves, skeleton curves, displacement ductility, failure patterns and process, stiffness degradation, shear-resistant strength of joints, etc. The results show that: first, the failure process of these three specimens is all from the beams to the columns, so this pattern meets the requirement of seismic design; second, the failure patterns of members are bending or bending with compression, but not shear or bonded damage. Some joints were damaged, as a result, the design of joint is one of the critical problems; third, the displacement ductility of them is qualified; fourth, strengthening the bottom story of the frame with wide specially shaped columns is able to increase the seismic performance to some extent. In conclusion, the seismic performances of experimental frames are well qualified.2. For simplifying the complication of nonlinear properties of materials and insuring calculating precision, the theories of plastic hinge and sectional fiber model were introduced to theoretical study of this frame structure. The experimental specimens were simulated and analyzed. Compared with the experimental results, the theoretical analysis models proposed in this thesis are effect to study the seismic performances of RC frames with specially shaped columns.3. Based on the proper evaluation of the seismic performance of RC frames, a new performance-based seismic design methodology is proposed, with new design methods, process, and design equations. The general procedures are: seismic performance aims were discussed and determined, after the performance relationship of the integrated structure and its members was established, and with the application of displacement respond spectrum, a new performance-based seismic design method was proposed. Actually, its methodology can also be applied to the RC frames with specially shaped columns.