Abstract: (17543 Views)
Pushover analysis is a simplified nonlinear analysis technique that can be used to
estimate the dynamic demands imposed on a structure under earthquake excitations. One of the first
steps taken in this approximate solution is to assess the maximum roof displacement, known as
target displacement, using the base shear versus roof displacement diagram. That could be done by
the so-called dynamic pushover analysis, i.e. a dynamic time history analysis of an equivalent single
degree of freedom model of the original system, as well as other available approximate static
methods. In this paper, a number of load patterns, including a new approach, are considered to
construct the related pushover curves. In a so-called dynamic pushover analysis, the bi-linear and
tri-linear approximations of these pushover curves were used to assess the target displacements by
performing dynamic nonlinear time history analyses. The results obtained for five different special
moment resisting steel frames, using five earthquake records were compared with those resulted
from the time history analysis of the original system. It is shown that the dynamic pushover analysis
approach, specially, with the tri-linear approximation of the pushover curves, proves to have a
better accuracy in assessing the target displacements. On the other hand, when nonlinear static
procedure seems adequate, no specific preference is observed in using more complicated static
procedures (proposed by codes) compared to the simple first mode target displacement assessment.
Type of Study:
Research Paper |