Optimal FRP-strengthening strategy for corrosion-affected reinforced concrete columns

Abstract Deterioration of reinforced concrete (RC) structures is unavoidable after their long time in service, with corrosion being the major mechanism of deterioration. In order to ensure safety of deteriorated structures, an effective rehabilitation plan is essential. Although considerable research on strengthening of RC structures using fibre-reinforced polymers (FRPs) composites has been undertaken, more is on the methods of strengthening and effects of corrosion on strength of RC columns than that on the prediction of optimum strengthening time. This paper presents a methodology for determining the optimal strengthening time and the required number of FRP layers for corrosion-affected RC structures with application to columns. The methodology is based on the time-dependent reliability method and the renewal theory. An example is provided to illustrate the application of the proposed methodology. It is found in this study that an optimum point for the formulated objective function exists, and that outcomes of optimisation problem, i.e. strengthening time and number of required FRP layers, are sensitive to corrosion rate. The significance of the proposed methodology is that it provides guidance for practitioners and asset managers to decide when and how to strengthen deteriorated structural members.

[1]  Tao Xie,et al.  Reliability Engineering , 2017, IEEE Softw..

[2]  Yong Lu,et al.  Probabilistic Drift Limits and Performance Evaluation of Reinforced Concrete Columns , 2005 .

[3]  Bruce R. Ellingwood,et al.  MAINTAINING RELIABILITY OF CONCRETE STRUCTURES. II: OPTIMUM INSPECTION/REPAIR , 1994 .

[4]  Mark F. Green,et al.  Long-Term Monitoring of Carbon Fiber-Reinforced Polymer-Wrapped Reinforced Concrete Columns Under Severe Environment , 2006 .

[5]  A. K. S. Jardine,et al.  Maintenance, Replacement, and Reliability , 2021 .

[6]  Hamid R. Ronagh,et al.  Effects of cross-sectional shape on the reliability of RC columns , 2011 .

[7]  Muhammad N. S Hadi,et al.  Behaviour of FRP wrapped normal strength concrete columns under eccentric loading , 2006 .

[8]  Palle Thoft-Christensen,et al.  Optimal strategy for inspection and repair of structural systems , 1987 .

[9]  Vistasp M. Karbhari,et al.  Design factors, reliability, and durability prediction of wet layup carbon/epoxy used in external strengthening , 2007 .

[10]  Afshin Firouzi,et al.  Efficient Solution for Calculation of Upcrossing Rate of Nonstationary Gaussian Process , 2018 .

[11]  R. K. Ursem.  Multi-objective Optimization using Evolutionary Algorithms , 2009 .

[12]  Michael D. A. Thomas,et al.  Accelerated corrosion and repair of reinforced concrete columns using carbon fibre reinforced polymer sheets , 2000 .

[13]  Bruno Sudret,et al.  The PHI2 method: a way to compute time-variant reliability , 2004, Reliab. Eng. Syst. Saf..

[14]  Stavroula J. Pantazopoulou,et al.  REPAIR OF CORROSION-DAMAGED COLUMNS WITH FRP WRAPS , 2001 .

[15]  Yanchun Yun,et al.  Effect of predamage on the stress-strain relationship of confined concrete under monotonic loading , 2014 .

[16]  Richard Sause,et al.  Axial Behavior of Reinforced Concrete Columns Confined with FRP Jackets , 2001 .

[17]  Omar Chaallal,et al.  Performance of fiber-reinforced polymer-wrapped reinforced concrete column under combined axial-flexural loading , 2000 .

[18]  Andrzej S. Nowak,et al.  Reliability analysis for eccentrically loaded columns , 2005 .

[19]  Andrew Chan,et al.  Residual capacity of corroded reinforcing bars , 2005 .

[20]  K W Neale,et al.  Confinement of reinforced concrete columns with fibre-reinforced composite sheets — an experimental study , 1999 .

[21]  Joan R. Casas,et al.  Partial safety factors for CFRP-wrapped bridge piers: Model assessment and calibration , 2014 .

[22]  Mark G. Stewart,et al.  Reliability and Model Accuracy for High-Strength Concrete Column Design , 1999 .

[23]  Ying Zou,et al.  Reliability assessment of FRP-confined concrete columns designed for buildings , 2011 .

[24]  Togay Ozbakkaloglu,et al.  Confinement Model for FRP-Confined High-Strength Concrete , 2014 .

[25]  Scott T Smith,et al.  Experimental testing and analytical modeling of CFRP-confined large circular RC columns subjected to cyclic axial compression , 2012 .

[26]  Vistasp M. Karbhari,et al.  Consideration of material variability in reliability analysis of FRP strengthened bridge decks , 2005 .

[27]  Pierre Labossière,et al.  Axial Testing of Rectangular Column Models Confined with Composites , 2000 .

[28]  Tarek H. Almusallam,et al.  Behavior of normal and high-strength concrete cylinders confined with E-glass/epoxy composite laminates , 2007 .

[29]  Ralejs Tepfers,et al.  CONCRETE CYLINDERS CONFINED BY CFRP SHEETS SUBJECTED TO CYCLIC AXIAL COMPRESSIVE LOAD , 2003 .

[30]  Zhimin Wu,et al.  Experimental study on partially deteriorated strength concrete columns confined with CFRP , 2009 .

[31]  D. Darwin,et al.  Statistical Analysis of the Mechanical Properties and Weight of Reinforcing Bars , 2004 .

[32]  Dan M. Frangopol,et al.  Lifetime Performance Analysis of Existing Reinforced Concrete Bridges. I: Theory , 2005 .

[33]  Robert E. Melchers,et al.  Effect of reinforcement corrosion on reliability of highway bridges , 1998 .

[34]  R. Realfonzo,et al.  Concrete confined by FRP systems: Confinement efficiency and design strength models , 2011 .

[35]  A. Helba,et al.  Reinforced Concrete Structures , 1944, Nature.

[36]  J. Teng,et al.  Design-oriented stress–strain model for FRP-confined concrete , 2003 .

[37]  Riyad S Aboutaha,et al.  Strength Evaluation of Deteriorated RC Bridge Columns , 2008 .

[38]  Dan M. Frangopol,et al.  Optimization of Life-Cycle Maintenance of Deteriorating Bridges with Respect to Expected Annual System Failure Rate and Expected Cumulative Cost , 2014 .

[39]  Hamid Saadatmanesh,et al.  STRENGTH AND DUCTILITY OF CONCRETE COLUMNS EXTERNALLY REINFORCED WITH FIBER COMPOSITE STRAPS , 1994 .

[40]  Abdeldjelil Belarbi,et al.  Effects of Corrosion of Steel Reinforcement on RC Columns Wrapped with FRP Sheets , 2009 .

[41]  Mark G. Stewart,et al.  Mechanical behaviour of pitting corrosion of flexural and shear reinforcement and its effect on structural reliability of corroding RC beams , 2009 .

[42]  Wei Wang,et al.  Behavior of FRP Jacketed Concrete Columns under Eccentric Loading , 2001 .

[43]  Amir Mirmiran,et al.  Behavior of Concrete Columns Confined by Fiber Composites , 1997 .

[44]  Robert E. Melchers,et al.  Structural Reliability: Analysis and Prediction , 1987 .

[45]  Stephanie L. Walkup,et al.  Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete Structures (ACI 440.2R-02) , 2005 .

[46]  Baris Binici,et al.  Design of FRPs in circular bridge column retrofits for ductility enhancement , 2008 .

[47]  Tamer El Maaddawy,et al.  Post-repair performance of eccentrically loaded RC columns wrapped with CFRP composites , 2008 .

[48]  C. Q. Li,et al.  Outcrossings from Convex Polyhedrons for Nonstationary Gaussian Processes , 1993 .

[49]  T. Kaku,et al.  EVALUATION OF CONFINING EFFECTS OF CFRP SHEETS ON REINFORCED CONCRETE MEMBERS , 1998 .

[50]  Abul K. Azad,et al.  Capacity of Corrosion-Damaged Eccentrically Loaded Reinforced Concrete Columns , 2014 .

[51]  Hassan Baji,et al.  Calibration of the FRP Resistance Reduction Factor for FRP-Confined Reinforced Concrete Building Columns , 2017 .

[52]  Dimitri V. Val,et al.  Reliability of Fiber-Reinforced Polymer-Confined Reinforced Concrete Columns , 2003 .

[53]  Chun‐Qing Li,et al.  Probabilistic Design Models for Ultimate Strength and Strain of FRP-Confined Concrete , 2016 .

[54]  Rajan Sen,et al.  Advances in the application of FRP for repairing corrosion damage , 2003 .

[55]  Robert E. Melchers,et al.  Life‐Cycle Performance of RC Bridges: Probabilistic Approach , 2000 .

[56]  L. Hollaway.  A review of the present and future utilisation of FRP composites in the civil infrastructure with reference to their important in-service properties , 2010 .

[57]  Hamid R. Ronagh,et al.  Probabilistic assessment of FRP-confined reinforced concrete columns , 2016 .