Title:
Lumped-Plasticity Models for Performance Simulation of Bridge Columns
Author(s):
Michael P. Berry, Dawn E. Lehman, and Laura N. Lowes
Publication:
Structural Journal
Volume:
105
Issue:
3
Appears on pages(s):
270-279
Keywords:
bridge columns; damage; design; drift; plastic-hinge length; plastic rotation; strain
DOI:
10.14359/19786
Date:
5/1/2008
Abstract:
The current state of practice in bridge seismic design focuses on achieving life-safety performance under a maximum credible earthquake. Typically, a lumped-plasticity model, which is based on a specified plastic-hinge length expression, is employed to estimate the ultimate displacement capacity. In contrast to current design guidelines, performance-based earthquake engineering (PBEE) requires assessment of damage for multiple demand levels. Thus, implementation of PBEE of bridges requires analytical methods capable of predicting bridge damage for multiple levels of earthquake demand. This paper evaluates models for PBEE of bridge columns, including new expressions for effective elastic stiffness, plastic-hinge length, and strain at onset of bar buckling. Data from 37 tests of large-scale circular bridge columns with modern (post- 1980) design details were used for model evaluation and development. The models were used to compute displacements and strains associated with various damage states and the resulting mean values and standard deviations. In comparison with existing models, the new model provides a more accurate and precise method for predicting damage in bridge columns.