Effects of Lateral Confinement on Concrete Columns Reinforced with Steel Bars with Uncertain Yield Strength

• Type: Article in International Scientific Journal
• Date: 2025

Authors

Khan, MS (Author) Other; Rafi, MM (Author) Other; Humberto Varum (Author) FEUP

Journal

The Journal is awaiting validation by the Administrative Services.

Title: JOURNAL OF STRUCTURAL DESIGN AND CONSTRUCTION PRACTICE

Vol. 30

ISSN: 2996-5136

Indexing

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Other information

Authenticus ID: P-019-SVA

DOI: 10.1061/jsdccc.sceng-1695

Abstract (EN): This paper investigates the impact of uncertain mechanical properties of reinforcement bars on the performance of RC columns under lateral load. Experimental tests were conducted on three full-scale RC columns featuring lap-spliced hot-rolled thermo-mechanically treated longitudinal bars, whose properties may not conform to stringent manufacturing standards typically found in developed countries. The paper assesses the influence of concrete confinement and core area on the behavior of RC columns reinforced with such rebars, characterized by uncertain mechanical properties. The tests revealed an underestimation of splice length due to an unintended increase in rebar yield strength, affecting column structural behavior. Although initial cracks were similar, the severely damaged region shifted near the dowel bar ends in the column with lesser confinement due to rebar slip, influencing flexural rigidity and curvature distribution. The results revealed that increasing confinement and core area enhanced the lateral load capacity and ultimate rotation by up to 32% and 64%, respectively. However, ductility remained unaffected. The experimental flexural capacity was up to 8% lower than predicted, accounting for concrete confinement by closely spaced lateral stirrups. Similarly, the rotation capacity was up to 12% lower than predictions from prevalent code methods. These discrepancies are attributed to the unintended increase in rebar yield strength. A modification to the method recommended by the code of practice for assessing the plastic rotation capacity of columns with insufficient splice lengths has been proposed that aligns well with the experimental data.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 12