A Study On Ductility Behaviors Of R.C Arbitrarily Inequiaxial Special-shaped Columns

As its width is generally consistent with thickness of wall, avoiding the shortcoming of rectangular columns' prominence in corridor and interior, making buildings more beautiful and enhancing the effectively using area of room, specially shaped R.C columns in civil engineering is getting wide application. However in many projects about specially shaped R.C columns, arbitrarily inequiaxial special-shaped columns usually exist as a result of architectural and structural need. Some scholars home and broad made a little study in this field, but it mostly focus on the load-bearing capacity, and study on its ductility, a kind of anti-seismic performance, is very scarceBased on the method of nonlinear analysis of complete response process, the curvature ductility ratio for R.C arbitrarily inequiaxial T-shaped, L-shaped and "十"shaped columns subjected to 792 load conditions is calculated using compiled C++ programme. On the basis of calculation results, the factors influencing the worst load orientation are analyzed and load orientation of the least curvature ductility of three kinds of sections is presented.Furthermore a analysis of failure mechanism for R.C arbitrarily inequiaxial special-shaped columns subjected to biaxially eccentric loading is made, the failure character is clarified under different axial compression ratio, the strain distribution in the section under yielding state and limit state is presented, and the corresponding M -φ curves are drew.Then all kinds of factors influencing curvature ductility ratio are analyzed, the variation regularity of curvature ductility is summarized and the order for all kinds offactors in term of the degree of influence is obtained. Finally three kinds of usual methods to determinate the limit values for axial compression ratio of frame columns, their merits and shortcomings are analyzed according to comparison and in the end this paper adopts the measure of curvature ductility to determinate the limit values for axial compression ratio of the arbitrarily inequiaxial special-shaped R.C columns.