A fibre model to simulate the cross-sectional behaviour of reinforced concrete columns under multi-directional earthquake loading

The sense of direction and the magnitude of horizontal ground accelerations due to earthquakes are not constant, but are variables within the duration of an earthquake. Furthermore, varying vertical ground accelerations appea r. As a result, columns of reinforced concrete space-frame structures suffe r multi-directional and time-variable excitations during earthquakes. To an alyse the structural response to those excitations more accurately, a fibre model describing the nonlinear behaviour of reinforced concrete cross-sect ions under multi-directional actions is presented. Diagrams showing yield f orce couples and corresponding plastic curvature capacity as well as a comp uter program to calculate epsilon, kappa(y), kappa(z) <-> N, M-y, M-z inter action for free force- and displacement-combinations are developed. (C) 200 0 Civil-Comp Ltd. and Elsevier Science Ltd. All rights reserved.