Title:
Assessment of Use of Steel Bars with Unintended High Strength in Tied Columns
Author(s):
Muhammad Masood Rafi and Muhammad Saad Khan
Publication:
Structural Journal
Volume:
121
Issue:
5
Appears on pages(s):
65-76
Keywords:
curvature; moment capacity; Monte Carlo simulation; reinforced concrete columns; strength-reduction factor; tensile strain
DOI:
10.14359/51740852
Date:
9/1/2024
Abstract:
This paper presents the details of the analyses which were
conducted to study the effects of steel reinforcing bars with unintended high strength on the behaviors of reinforced concrete (RC) columns. The influence of these bars on the column strength and strength-reduction factors were investigated. The former was
studied with the help of column axial load-moment interaction
diagrams, while a reliability analysis was carried out for the latter.
Four different column cross sections reinforced with reinforcement
ratios varying from 1 to 4% were included in the analysis. Other
variables included concrete compressive and reinforcing bar yield
strengths. The effects of the aforementioned variables were also
considered on the development length of the reinforcing bars in
tension and compression. It was found that the use of reinforcing
bars with unintended high strength could change column behavior
to compression-controlled at a lesser axial load level, which is
accompanied by a reduction in the curvature capacity. Modifications
have been suggested to control the negative effects of unintended
high strength of bars on the column behavior and bar development
length. Strength-reduction factors for RC sections ranging
from compression-controlled to tension-controlled regions have
also been proposed, which differ from those suggested by the prevalent code of practice.