Title:
Buckling and Fracture of Grade 60 Steel Reinforcement in Circular Columns
Author(s):
Diego Sosa, Gunay Gina Aliyeva, and Mervyn Kowalsky
Publication:
Structural Journal
Volume:
123
Issue:
2
Appears on pages(s):
17-28
Keywords:
buckling; damage limit states; fracture; low-cycle fatigue; reinforced concrete (RC) columns
DOI:
10.14359/51749162
Date:
3/1/2026
Abstract:
In performance-based seismic design, buckling and fracture of longitudinal steel in reinforced concrete columns are damage limit states that may be considered for damage control and near-collapse, respectively. This study evaluates the progression of buckling instability, which eventually leads to bar fracture, based on bending strains measured in buckled bars from cyclic quasi-static column tests. Buckling-induced bending strains are calculated with bare-bar fiber models and experimental buckled shapes of longitudinal reinforcement in the column data set. This study proposes an empirical equation that calculates the buckling-induced bending strain based on column displacement ductility, low-cycle fatigue, and column design parameters for Grade 60 steel. This study also identifies the buckling-induced bending strains that trigger transverse steel yielding, visual bar buckling, and brittle bar fracture.
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