Research On Ductility Of Reinforced Concrete Arbitrarily Inequiaxial Special-Shaped Columns

The R.C. frame structures with special-shaped columns were used more widely in the housing buildings, and there are many researches on the equiaxial special-shaped columns, while there is little research on the inequiaxial special-shaped columns, especially on the ductility of the inequiaxial special-shaped columns. The ductility of the R.C. inequiaxial L-shaped, T-shaped and +-shaped columns were detailed researched with the method of full-range nonlinear analysis in this dissertation, the chief contents and achievements are shown as follows:1. A method for analysis of the inequiaxial special-shaped columns is established. The computer program(SCDP) for analysis of the ductility of the special-shaped columns was compiled in Visual C++ surroundings. Comparison in theoretical results calculated by the SCDP program with experimental results was made and the results obtained show the correctness and applicability of the software.2. 275 sets of inequiaxial L-shaped columns, 243 sets of inequiaxial T -shaped columns and 223 sets of inequiaxial+-shaped columns were calculated by the SCDP program. Many relevant factors including angles of loading, axial force ratio, spacing of lateral reinforcement and change of section for the ductility of the inequiaxial special-shaped columns were analyzed, and its ductility behavior were summarized.3. Considering back and forth of earthquake loading, this dissertation researched the ductility behavior of the R.C. frame structures with special-shaped columns on the average displacement ductility ratio, it also set up transform formula from curvature ductility ratio to displacement ductility ratio and analyzed the difference between them.4. Comparison and analysis between the inequiaxial L-shaped , T-shaped and + -shaped columns and the equiaxial special- shaped columns were made, the calculated results obtained show that the ductility of inequiaxial L-shaped columns are approaching to the equiaxial L-shaped columns, while the ductility of inequiaxial T -shaped and +-shaped columns are decreased.5. On the basis of the theoretical analysis and the calculated analysis, this dissertation proposed simplified calculating formulae for displacement ductility ratio of inequiaxial special-shaped columns with the method of least squares, and the limit value of axial compression ratio of the inequiaxial special-shaped columns were then gave.The research results of this dissertation are of good reference for actual project designing as well as a theoretical foundation to compile the relevant design criterion.