Title:
Buckling and Fracture of Grade 60 Steel Reinforcement in Circular Columns (Prepublished)
Author(s):
Diego Sosa, Gunay Aliyeva, and Mervyn Kowalsky
Publication:
Structural Journal
Volume:
Issue:
Appears on pages(s):
Keywords:
buckling; damage limit states; fracture; low-cycle fatigue; reinforced concrete columns
DOI:
10.14359/51749162
Date:
9/10/2025
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 of 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.