VERIFICATION OF AN ADAPTIVE PUSHOVER TECHNIQUE FOR THE 3D CASE

The displacement based adaptive pushover (DAP) technique is an improved pushover technique in which a set of laterally imposed displacements, rather than forces, are applied in adaptive fashion to the structure. The technique has been extensively tested for two dimensional planar structures with considerable improvements when compared to conventional pushover techniques. It seems paramount, then, to verify its efficiency for the 3D case, in which it is hoped that the algorithm, will also lead to improved seismic response predictions. Herein, the DAP methodology is evaluated for a 3D asymmetric building structure (the SPEAR building). It is investigated how the pushover results of a spatial model can be best compared with the nonlinear dynamic envelops. Bidirectional excitation is considered. Seven different ground motions were used, all fitted to the same code-defined response spectrum. Additionally, the DAP methodology has been compared with a conventional non-adaptive pushover, where lateral forces in a triangular pattern are applied. Good agreement is obtained with the time history analysis results although torsional induced interstorey drifts are slightly underestimated. The advantages of the methodology are clear when compared to its non-adaptive conventional counterpart. Further testing on more irregular and complex buildings would manage to fully evidence the benefits of the method