Refined modeling of reinforced concrete columns of seismic analysis

The fiber representation of a section is extended to make possible the analysis of reinforced concrete or steel members independently or as part of two dimensional frames. Slice locations are specified along the length of the element. Each slice is further discretized into steel and/or concrete fibers. By monitoring the various fibers and slices, it is possible to obtain the local response at critical sections including moment curvature and shear histories. Bond slip and shear effects are not considered so the multislice fiber element is suitably for modeling beams and columns in a steel or reinforced concrete especially when the effects of axial loads on strength and stiffness are significant. The element can account for axial load bending moment interaction and the pinching of hysteresis loops due to compressive loads acting on the element. The functioning of the element is tested separately and as part of a general dynamic two dimensional frame analysis program.