Prediction model for longitudinal reinforcement buckling in reinforced concrete beams and columns with rectilinear hoops
Journal
Engineering Structures
Journal Volume
353
Start Page
122312
ISSN
01410296
Date Issued
2026-04-15
Author(s)
Sutejo, Hermawan
Abstract
Buckling of longitudinal reinforcement in compression, often followed by low-cycle fatigue fracture in tension, is a primary mechanism driving strength degradation in reinforced concrete flexural members subjected to large-displacement reversals. This study proposes a mechanics-based analytical model to predict the buckling length of longitudinal reinforcement restrained by rectilinear transverse reinforcement. The model captures buckling lengths over a non-integer interval of tie spacings by incorporating end transition regions beyond the outermost hoops bounding the buckling region. The buckling-restraint stiffness is formulated by combining axial and bending components. The axial component is adjusted to reflect hoop type and hook-bent angle through a geometric effectiveness factor, while the bending component is evaluated from the flexural response of transverse ties. The model is validated using 38 beam and 32 column specimens collected from the literature. The proposed model achieves improved accuracy relative to the models by Su et al. and Dhakal & Maekawa, with average prediction errors of 6.5 % for beams and 10.1 % for columns, compared to 9.8 % and 12.3 % for Su et al. and 26.0 % and 22.3 % for Dhakal & Maekawa, respectively. Parametric reanalysis shows that excluding either the axial reduction factor or the bending component increases the error by about 20 %, and neglecting both increases the error by up to 55 %, demonstrating that both mechanisms are essential for reliable buckling-length prediction.
Subjects
Beams
Buckling
Buckling length
Columns
Longitudinal reinforcement
Springs
Stiffness
Transverse reinforcement
Publisher
Elsevier Ltd
Type
journal article