determination of failure surface for reinforced concrete shear walls with arbitrary shapes

In order to understand the seismic performance of structures , implementation of nonlinear analysis is necessary . To perform nonlinear analysis having access to details of section's failure surface is essential . The failure surface of a cross section can be defined as the locus of points that correspond to ultimate strength. in this article a new quick and efficient method based on fibre method concepts is presented that is usefull to calculate failure surfaces for RC shear walls with arbitrary shapes such as I ,T and L shapes. in here different nonlinear behavior for concrete in compression and tension are assumed. elastic perfect plastic behavior is considered for steel bars . moment-curvature diagrams bending moment axial force interaction cures and biaxial bending -axial force failure surfaces are defined by this method.