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Seismic Energy Based Fatigue Damage Analysis of Bridge Columns: Part 1 - Evaluation of Seismic Capacity

G.A.Chang, J.B.Mander

NCEER-94-0006 | 3/14/1994 | 240 pages

About the Report:

TOC: The table of contents is provided.

Keywords: Reinforced Concrete Bridge Columns, Fatigue Capacity, Energy Absorption, Hysteresis, Damage Analysis, Fiber Element Models, Mild Steel Reinforcement, Computer Programs, Prestressing Reinforcement, Stress Strain Relationships, UB-COLA, and Cyclic Inelastic Strut Tie (CIST) Model.

Abstract: This study is concerned with the computational modeling of energy absorption (fatigue) capacity of reinforced concrete bridge columns by using a cyclic dynamic Fiber Element computational model. The results may be used with a hysteretic rule to generate seismic energy demand. By comparing the ratio of energy demand to capacity, inferences of column damageability or fatigue resistance can be made. A complete analysis methodology for bridge columns is developed. The hysteretic behavior of ordinary mild steel as well as high threadbar prestressing reinforcement - stability, degradation and consistency of cyclic behavior - is explained. An energy based universally applicable low cycle fatigue model for such reinforcing steels is proposed. A hysteretic model for confined and unconfined concrete subjected to both tension or compression cyclic loading is developed. The model is also capable of simulating gradual crack closure under cyclic loading. A cyclic inelastic strut-tie (CIST) model is developed, in which the comprehensive concrete model stress-strain proved to be suitable. A fiber element based column analysis program UB-COLA is also developed, which is capable of accurately predicting the behavior of reinforced concrete columns subjected to inelastic cyclic deformations. The program is useful in predicting the failure model of high axial load columns. For shear critical columns, the cyclic inelastic behavior is accurately simulated through the CIST modeling technique.