Use of Pushover Results

Pushover analysis has been the preferred method for seismic performance evaluation of structures by the major rehabilitation guidelines and codes because it is 5 conceptually and computationally simple. Pushover analysis allows tracing the sequence of yielding and failure on member and structural level as well as the progress of overall capacity curve of the structure. The expectation from pushover analysis is to estimate critical response parameters imposed on structural system and its components as close as possible to those predicted by nonlinear dynamic analysis. Pushover analyses provide information on many response characteristics that cannot be obtained from an elastic static or elastic dynamic analysis. These are:

• Estimates of inter-story drifts and its distribution along the height.
• Determination of force demands on brittle members, such as axial force demands on columns, moment demands on beam-column connections
• Determination of deformation demands for ductile members
• Identification of location of weak points in the structure (or potential failure modes)
• Consequences of strength deterioration of individual members on the behavior of structural system
• identification of strength discontinuities in plan or elevation that will lead to changes in dynamic characteristics in the inelastic range
• verification of the completeness and adequacy of load path

Pushover analysis also exposes design weaknesses that may remain hidden in an Elastic analysis. These are story mechanisms, excessive deformation demands, strength irregularities and overloads on potentially brittle members.