Residual flexural strength of reinforced concrete beams with unbonded reinforcement

Fares Jnaid, Riyad S Aboutaha

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Corrosion is the primary limit state in steel reinforced concrete (RC) beams in severe environments. Corrosion of steel bars causes a decrease in steel bar section, loss of bond, and delamination of concrete cover. Very limited models have been developed for estimating the residual flexural strength of corroded RC beams. These models do not differentiate between the decrease in flexural strength due to loss of steel section, or due to loss of bond between the steel bars and the surrounding concrete. This paper presents an analytical model for estimating the residual flexural strength of RC beams with unbonded bars. In this research, the "neutral axis depth" approach, which is widely used to obtain the ultimate stress in prestressed concrete, was adopted and modified to estimate the residual ultimate capacity of concrete beams reinforced with unbonded steel bars. A finite element analysis (FEA) model was developed, and the results were verified against experimental data by others. The experimental data of a total of 109 RC beams covered many variables: span-depth ratio, reinforcement ratio, concrete compressive strength, length of unbonded zone, and type of applied load. Using the aforementioned data and FEA model, an analytical model was developed to calculate the ultimate strength of concrete beams reinforced with unbonded steel bars. The results of this investigation suggest that the reinforcement ratio and the unbonded length have a major effect on the residual flexural strength of RC beams with unbonded reinforcement, whereas the other variables have limited impact.

Original languageEnglish (US)
Pages (from-to)1419-1430
Number of pages12
JournalACI Structural Journal
Volume111
Issue number6
DOIs
StatePublished - Nov 1 2014

Fingerprint

Bending strength
Reinforced concrete
Reinforcement
Steel
Concretes
Analytical models
Corrosion
Finite element method
Prestressed concrete
Delamination
Compressive strength

Keywords

  • Beam
  • Evaluation
  • Finite element analysis
  • Flexural strength
  • Reinforced concrete
  • Residual strength
  • Unbonded bars

ASJC Scopus subject areas

  • Building and Construction
  • Civil and Structural Engineering

Cite this

Residual flexural strength of reinforced concrete beams with unbonded reinforcement. / Jnaid, Fares; Aboutaha, Riyad S.

In: ACI Structural Journal, Vol. 111, No. 6, 01.11.2014, p. 1419-1430.

Research output: Contribution to journalArticle

@article{59637c04f1724281a6288b4add26c24e,
title = "Residual flexural strength of reinforced concrete beams with unbonded reinforcement",
abstract = "Corrosion is the primary limit state in steel reinforced concrete (RC) beams in severe environments. Corrosion of steel bars causes a decrease in steel bar section, loss of bond, and delamination of concrete cover. Very limited models have been developed for estimating the residual flexural strength of corroded RC beams. These models do not differentiate between the decrease in flexural strength due to loss of steel section, or due to loss of bond between the steel bars and the surrounding concrete. This paper presents an analytical model for estimating the residual flexural strength of RC beams with unbonded bars. In this research, the {"}neutral axis depth{"} approach, which is widely used to obtain the ultimate stress in prestressed concrete, was adopted and modified to estimate the residual ultimate capacity of concrete beams reinforced with unbonded steel bars. A finite element analysis (FEA) model was developed, and the results were verified against experimental data by others. The experimental data of a total of 109 RC beams covered many variables: span-depth ratio, reinforcement ratio, concrete compressive strength, length of unbonded zone, and type of applied load. Using the aforementioned data and FEA model, an analytical model was developed to calculate the ultimate strength of concrete beams reinforced with unbonded steel bars. The results of this investigation suggest that the reinforcement ratio and the unbonded length have a major effect on the residual flexural strength of RC beams with unbonded reinforcement, whereas the other variables have limited impact.",
keywords = "Beam, Evaluation, Finite element analysis, Flexural strength, Reinforced concrete, Residual strength, Unbonded bars",
author = "Fares Jnaid and Aboutaha, {Riyad S}",
year = "2014",
month = "11",
day = "1",
doi = "10.14359/51686975",
language = "English (US)",
volume = "111",
pages = "1419--1430",
journal = "ACI Structural Journal",
issn = "0889-3241",
publisher = "American Concrete Institute",
number = "6",

}

TY - JOUR

T1 - Residual flexural strength of reinforced concrete beams with unbonded reinforcement

AU - Jnaid, Fares

AU - Aboutaha, Riyad S

PY - 2014/11/1

Y1 - 2014/11/1

N2 - Corrosion is the primary limit state in steel reinforced concrete (RC) beams in severe environments. Corrosion of steel bars causes a decrease in steel bar section, loss of bond, and delamination of concrete cover. Very limited models have been developed for estimating the residual flexural strength of corroded RC beams. These models do not differentiate between the decrease in flexural strength due to loss of steel section, or due to loss of bond between the steel bars and the surrounding concrete. This paper presents an analytical model for estimating the residual flexural strength of RC beams with unbonded bars. In this research, the "neutral axis depth" approach, which is widely used to obtain the ultimate stress in prestressed concrete, was adopted and modified to estimate the residual ultimate capacity of concrete beams reinforced with unbonded steel bars. A finite element analysis (FEA) model was developed, and the results were verified against experimental data by others. The experimental data of a total of 109 RC beams covered many variables: span-depth ratio, reinforcement ratio, concrete compressive strength, length of unbonded zone, and type of applied load. Using the aforementioned data and FEA model, an analytical model was developed to calculate the ultimate strength of concrete beams reinforced with unbonded steel bars. The results of this investigation suggest that the reinforcement ratio and the unbonded length have a major effect on the residual flexural strength of RC beams with unbonded reinforcement, whereas the other variables have limited impact.

AB - Corrosion is the primary limit state in steel reinforced concrete (RC) beams in severe environments. Corrosion of steel bars causes a decrease in steel bar section, loss of bond, and delamination of concrete cover. Very limited models have been developed for estimating the residual flexural strength of corroded RC beams. These models do not differentiate between the decrease in flexural strength due to loss of steel section, or due to loss of bond between the steel bars and the surrounding concrete. This paper presents an analytical model for estimating the residual flexural strength of RC beams with unbonded bars. In this research, the "neutral axis depth" approach, which is widely used to obtain the ultimate stress in prestressed concrete, was adopted and modified to estimate the residual ultimate capacity of concrete beams reinforced with unbonded steel bars. A finite element analysis (FEA) model was developed, and the results were verified against experimental data by others. The experimental data of a total of 109 RC beams covered many variables: span-depth ratio, reinforcement ratio, concrete compressive strength, length of unbonded zone, and type of applied load. Using the aforementioned data and FEA model, an analytical model was developed to calculate the ultimate strength of concrete beams reinforced with unbonded steel bars. The results of this investigation suggest that the reinforcement ratio and the unbonded length have a major effect on the residual flexural strength of RC beams with unbonded reinforcement, whereas the other variables have limited impact.

KW - Beam

KW - Evaluation

KW - Finite element analysis

KW - Flexural strength

KW - Reinforced concrete

KW - Residual strength

KW - Unbonded bars

UR - http://www.scopus.com/inward/record.url?scp=84917741808&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84917741808&partnerID=8YFLogxK

U2 - 10.14359/51686975

DO - 10.14359/51686975

M3 - Article

AN - SCOPUS:84917741808

VL - 111

SP - 1419

EP - 1430

JO - ACI Structural Journal

JF - ACI Structural Journal

SN - 0889-3241

IS - 6

ER -