09-04-2013, 08:44 PM
USING PUSHOVER ANALYSIS METHOD IN SEISMIC ANALYSIS OF BRIDGES
Author: Hamed AlAyed1 and Chung C. Fu2 | Size: 0.325 MB | Format: PDF | Quality: Unspecified | pages: 12
Nonlinear Static (Pushover) Procedure (NSP) is specified in the guidelines for seismic
rehabilitation of buildings presented by FEMA-273 [1] as an analytical procedure that can be used in
systematic rehabilitation of structures. However, those guidelines were presented to apply the
Displacement Coefficient Method (DCM) only for buildings. This study is intended to evaluate the
applicability of NSP by implementing the DCM to bridges. For comparison purposes, the Nonlinear
Dynamic Procedure (NDP) (or nonlinear time-history analysis), which is considered to be the most
accurate and reliable method of nonlinear seismic analysis, is also performed.
A three-span bridge of 97.5 meters (320 ft) in total length was analyzed using both the NSP-DCM
and nonlinear time-history. Nine time-histories were implemented to perform the nonlinear time-history
analysis. Three load patterns were used to represent distribution of the inertia forces resulting from
earthquakes. Demand (target) displacement, base shear, and deformation of plastic hinges obtained from
the NSP are compared with the corresponding values resulting from the nonlinear time history analysis.
Analysis was performed using two levels of seismic load intensities (Design level and Maximum
Considered Earthquake (MCE) level). Performance of the bridge was evaluated against these two seismic
loads. Comparison shows that the NSP gives conservative results, compared to the nonlinear time history
analysis, in the Design Level while it gives more conservative results in the MCE Level.
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