- Author
-
El-Bahy, A.
|
Kunnath, S. K.
|
Stone, W. C.
|
Taylor, A. W.
- Title
- Cumulative Seismic Damage of Circular Bridge Columns: Benchmark and Low-Cycle Fatigue Tests.
- Coporate
- Tilden Lobnitz, Cooper, FL
University of Central Florida, Orlando
National Institute of Standards and Technology, Gaithersburg, MD
KPFF Consulting Engineers, Seattle, WA
- Journal
-
ACI Structural Journal,
Vol. 96,
No. 4,
633-641,
July/August 1999
- Keywords
-
bridges (structures)
|
damage
|
reinforced concretes
|
piers
|
earthquakes
|
fatigue (materials)
|
structures
|
cyclic loads
|
ductility
|
material properties
- Identifiers
- earthquake-resistant structures; details of prototype and model; summary of reinforcing bar characteristics; benchmark tests; low-cycle fatigue tests; fatigue life relationship
- Abstract
- An experimental study was undertaken to investigate cumulative damage in reinforced concrete circular bridge piers subjected to a series of earthquake excitations. Twelve identical quarter-scale bridge columns, designed in accordance with current AASHTO specifications, were fabricated and tested to failure. This paper summarizes the results of Phase 1 testing that consisted of benchmark tests to establish the monotonic force-deformation envelope and the energy capacity under standard cyclic loads, and constant amplitude tests to determine the low-cycle fatigue characteristics of typical flexural bridge columns. A companion paper will present the results of variable amplitude testing that focused on the effects of load path on cumulative damage. Test observations indicate two potential failure modes: low cycle fatigue of the longitudinal reinforcing bars; and confinement failure due to rupture of the confining spirals. The former failure mode is associated with relatively large displacements amplitudes in excess of 4 percent lateral drift, while the latter is associated with a larger number of smaller amplitude cycles. A fatigue life expression is developed that can be used in damage-based seismic design of circular, flexural bridge columns.