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RELIABILITY ASSESSMENT OF
BRAIDED FRP REINFORCEMENT
FOR CONCRETE STRUCTURES
Sofia Antonopoulou & Ciaran McNally
University...
Outline
Background and Motivation
General Research Idea
Research Progress
Results
Conclusions
Background and Motivation
Deterioration of global infrastructure
Degradation of reinforced concrete structures due to
corr...
Background and Motivation
Replacement of steel as internal concrete reinforcement by
FRP composites
Fibre Reinforced Polym...
Background and Motivation
Limited information on FRP long-term durability in civil
engineering applications Real, in-situ ...
Background and Motivation
Design guidelines for the efficient use of FRPs in construction:
 ACI-440.1R
 CSA-S806-02
Manu...
Background and Motivation
Basic principle of braiding:
Interlacing of yarns in a diagonal direction -
Multiaxial Orientati...
Background and Motivation
Braided FRP reinforcement
Cost factor is related to geometrical & manufacturing parameters
like ...
General Research Idea
Aim of the project:
Main goal:
Design, Development, Optimisation & Performance
Evaluation of Basalt ...
Research Progress
Materials
 Basalt fibres
 PET fibres
 Epoxy resin
Manufacturing design & process of braided BFRP pref...
Research Progress
Manufacturing design & process of braided BFRP preforms
Braided BFRP preforms changing braiding paramete...
Results
Laboratory manufactured
BFRP preforms & rebars
using braiding & vacuum
assisted resin infusion
technique
Research Progress
Numerical analysis
Classical Lamination Theory
(CLT) numerical approach
Evaluation of elastic properties...
Results
Direct relation between braiding parameters
& rebar’s properties
!!(9)!
After the analysis on the mechanical prope...
Research Progress
Sensitivity Analysis
Sensitivity analysis on parameters affecting elastic modulus
of braided rebars
 Ev...
Results
The effect of braiding process is to reduce the
variation arising from the material input properties
Conclusions
 Direct relation between braiding parameters & rebar’s
properties.
 Pultruded FRP reinforcement Variation in...
THANK
YOU!
Training in Reducing
Uncertainty
in Structural Safety
2015 - 2018
sofia.antonopoulou@ucd.ie
www.esr1truss.blogs...
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"Reliability assessment of braided FRP reinforcement for concrete structures" presented at ESREL2017 by Sofia Antonopoulou

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Abstract: In recent years the long term durability of reinforced concrete structures has become a major concern. The effect of harsh loading conditions and aggressive environmental factors can lead to corrosion of reinforcing steel in civil engineering applications. This in turn leads to undesired repairs, additional costs and shorter service lives. Advanced composite materials, such as Basalt Fibre Reinforced Polymer (BFRP), have the capacity to significantly address this problem. These materials have enhanced physical properties such as higher mechanical and corrosion resistance, and have the potential to replace traditional steel rebars as tension reinforcement in concrete. There are however limitations that prevent their use on a larger scale, and lack of ductility is the most significant. Braiding techniques could provide the required performance benefits related to the additional ductility and flexibility needed, as well as enhancing the bond between FRP and concrete. If this is achieved, it has the potential to prevent a brittle failure and successfully meet strength, reliability and cost demands. This study focuses on the basics of materials characterization and reliability analysis of internal BFRP reinforcement for concrete structures towards design optimization for structural reliability over their service life.

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"Reliability assessment of braided FRP reinforcement for concrete structures" presented at ESREL2017 by Sofia Antonopoulou

  1. 1. RELIABILITY ASSESSMENT OF BRAIDED FRP REINFORCEMENT FOR CONCRETE STRUCTURES Sofia Antonopoulou & Ciaran McNally University College Dublin School of Civil Engineering This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 642453. 27th European Safety and Reliability Conference Training in Reducing Uncertainty in Structural Safety 2015 - 2018
  2. 2. Outline Background and Motivation General Research Idea Research Progress Results Conclusions
  3. 3. Background and Motivation Deterioration of global infrastructure Degradation of reinforced concrete structures due to corrosion of steel affects long-term durability, total service life, structural safety of RC elements Estimated global cost of corrosion ~ $ 2.5 trillion
  4. 4. Background and Motivation Replacement of steel as internal concrete reinforcement by FRP composites Fibre Reinforced Polymers consist of  High strength fibres  Polymer matrices Advanced properties of FRP  Corrosion resistance  High strength-to-weight ratio  Reduced life-cycle costs Main disadvantage of FRP Brittle failure without warning
  5. 5. Background and Motivation Limited information on FRP long-term durability in civil engineering applications Real, in-situ data are needed Durability of FRPs strongly dependent on  Type of fibre & matrix  Fibre content  Fibre-matrix interface  Orientation of fibres Degradation mechanisms Moisture, Alkalinity, Temperature, Fatigue
  6. 6. Background and Motivation Design guidelines for the efficient use of FRPs in construction:  ACI-440.1R  CSA-S806-02 Manufacture methods of FRP:  Pultrusion low cost & continuous process  Braiding additional ductility & increased bond with concrete
  7. 7. Background and Motivation Basic principle of braiding: Interlacing of yarns in a diagonal direction - Multiaxial Orientation Braiding Angle: Affects mechanical properties of braids
  8. 8. Background and Motivation Braided FRP reinforcement Cost factor is related to geometrical & manufacturing parameters like braiding angle, number of layers, elastic modulus. Sensitivity analysis How design variables influence the optimisation cost function Design Optimisation through Sensitivity Analysis Methods
  9. 9. General Research Idea Aim of the project: Main goal: Design, Development, Optimisation & Performance Evaluation of Basalt Fibre Reinforced Polymer composites, for internal concrete reinforcement, using braiding as a manufacturing technique Explore the potential of braided BFRP reinforcement in infrastructure applications
  10. 10. Research Progress Materials  Basalt fibres  PET fibres  Epoxy resin Manufacturing design & process of braided BFRP preforms ____________________________________________ ________ Material Property Basalt PET Epoxy resin______________________________________________ ______ Density (g/cm3 ) 2.7 1.39 1.15 Linear density (TEX) 300/ 600 97 - Yarn diameter (mm) 0.38/ 0.53 0.3 - Elastic modulus (GPa) 87/ 89 10 2.65
  11. 11. Research Progress Manufacturing design & process of braided BFRP preforms Braided BFRP preforms changing braiding parameters (angle, no of layers) 10 different braid configurations:  5 mm OD  8 mm OD  10 mm OD
  12. 12. Results Laboratory manufactured BFRP preforms & rebars using braiding & vacuum assisted resin infusion technique
  13. 13. Research Progress Numerical analysis Classical Lamination Theory (CLT) numerical approach Evaluation of elastic properties of braided composites Calculate each layer’s properties & define:  Thickness  Poisson’s ratio  Fibre volume fraction Estimate the effective longitudinal in-plane modulus of BFRP rebars
  14. 14. Results Direct relation between braiding parameters & rebar’s properties !!(9)! After the analysis on the mechanical properties of braided BFRP rebar, a sensitivity analysis is con- ducted on the parameters affecting cost as a function of elastic modulus. Firstly, the influence of fundamental material prop- erties (TEX, materials modulus, Poisson’s ratio) and braiding parameters (braiding angle) on rebar’s modulus was determined. Then, all parameters were ranked in order of influence and an initial estimation about the most important parameters for optimiza- tion was obtained. 8! RESULTS AND DISCUSSION Braided BFRP rebars were designed and manufac- tured in three different sizes and configurations (5, 8, 10 mm diameter) while changing key parameters (angle, no of layers) to achieve the desired structural geometry and meet the performance characteristics of existing rebar reinforcement. Manufactured com- posites are then numerically analysed and the effect of geometrical factors and processing conditions on their elastic properties is evaluated. In Table 2, technical braiding details are illustrat- ed along with the numerically determined effective longitudinal in-plane modulus ( ) using CLT ap- proach and Equations 1 – 9, while in Figure 4 a braided BFRP preform along with resin impregnated Table 2. Technical braiding details - Numerically determined elastic moduli & fibre content using CLT for braid OD (a) 5 mm, (b) 8 mm, (c) 10 mm______________________________________________ (a) 5 mm BFRP_____________________________________________ Layer Material Carriers OD Angle______________________________________________ 1 600 8 2.5 13 2 PET 32 3.8 11 3 PET 32 4.3 11 4 600 16 5.0 45_____________________________________________ 34.03 GPa_____________________________________________ φf 63.82 %___________________________________________________________________________________________ (b) 8 mm BFRP_____________________________________________ Layer Material Carriers OD Angle______________________________________________ 1 300 8 1.6 12 2 300 16 2.7 16 3 PET 32 3.5 10 4 600 16 4.5 25 5 600 16 5.2 26 6 PET 32 6.2 16 7 600 24 6.8 24 8 600 24 7.8 37_____________________________________________ 41.54 GPa_____________________________________________ φf 59.03 %___________________________________________________________________________________________ (c) 10 mm BFRP_____________________________________________ Layer Material Carriers OD Angle______________________________________________ 1 300 8 1.6 12 2 300 16 2.7 16 3 PET 32 3.5 10 4 600 16 4.3 42 5 600 16 5.2 41 6 PET 32 5.9 21 7 600 24 6.9 24 8 600 24 7.5 35 9 PET 24 8.6 39 10 600 24 9.2 31 (3) !!(9)! After the analysis on the mechanical properties of braided BFRP rebar, a sensitivity analysis is con- ducted on the parameters affecting cost as a function of elastic modulus. Firstly, the influence of fundamental material prop- erties (TEX, materials modulus, Poisson’s ratio) and braiding parameters (braiding angle) on rebar’s modulus was determined. Then, all parameters were ranked in order of influence and an initial estimation about the most important parameters for optimiza- tion was obtained. 8! RESULTS AND DISCUSSION Braided BFRP rebars were designed and manufac- tured in three different sizes and configurations (5, 8, 10 mm diameter) while changing key parameters (angle, no of layers) to achieve the desired structural geometry and meet the performance characteristics of existing rebar reinforcement. Manufactured com- posites are then numerically analysed and the effect of geometrical factors and processing conditions on their elastic properties is evaluated. In Table 2, technical braiding details are illustrat- ed along with the numerically determined effective longitudinal in-plane modulus ( ) using CLT ap- proach and Equations 1 – 9, while in Figure 4 a braided BFRP preform along with resin impregnated rebars in regular and spiral configuration are shown. The values presented are calculated using the mean Table 2. Technical braiding details - Numerically determined elastic moduli & fibre content using CLT for braid OD (a) 5 mm, (b) 8 mm, (c) 10 mm______________________________________________ (a) 5 mm BFRP_____________________________________________ Layer Material Carriers OD Angle______________________________________________ 1 600 8 2.5 13 2 PET 32 3.8 11 3 PET 32 4.3 11 4 600 16 5.0 45_____________________________________________ 34.03 GPa_____________________________________________ φf 63.82 %___________________________________________________________________________________________ (b) 8 mm BFRP_____________________________________________ Layer Material Carriers OD Angle______________________________________________ 1 300 8 1.6 12 2 300 16 2.7 16 3 PET 32 3.5 10 4 600 16 4.5 25 5 600 16 5.2 26 6 PET 32 6.2 16 7 600 24 6.8 24 8 600 24 7.8 37_____________________________________________ 41.54 GPa_____________________________________________ φf 59.03 %___________________________________________________________________________________________ (c) 10 mm BFRP_____________________________________________ Layer Material Carriers OD Angle______________________________________________ 1 300 8 1.6 12 2 300 16 2.7 16 3 PET 32 3.5 10 4 600 16 4.3 42 5 600 16 5.2 41 6 PET 32 5.9 21 7 600 24 6.9 24 8 600 24 7.5 35 9 PET 24 8.6 39 10 600 24 9.2 31 11 600 24 9.9 38_____________________________________________ 40.96 GPa_____________________________________________ (6) !!(9)! After the analysis on the mechanical properties of braided BFRP rebar, a sensitivity analysis is con- ducted on the parameters affecting cost as a function of elastic modulus. Firstly, the influence of fundamental material prop- erties (TEX, materials modulus, Poisson’s ratio) and braiding parameters (braiding angle) on rebar’s modulus was determined. Then, all parameters were ranked in order of influence and an initial estimation about the most important parameters for optimiza- tion was obtained. 8! RESULTS AND DISCUSSION Braided BFRP rebars were designed and manufac- tured in three different sizes and configurations (5, 8, 10 mm diameter) while changing key parameters (angle, no of layers) to achieve the desired structural geometry and meet the performance characteristics of existing rebar reinforcement. Manufactured com- posites are then numerically analysed and the effect of geometrical factors and processing conditions on their elastic properties is evaluated. In Table 2, technical braiding details are illustrat- ed along with the numerically determined effective longitudinal in-plane modulus ( ) using CLT ap- proach and Equations 1 – 9, while in Figure 4 a braided BFRP preform along with resin impregnated rebars in regular and spiral configuration are shown. The values presented are calculated using the mean properties as presented in Table 1. Table 2. Technical braiding details - Numerically determined elastic moduli & fibre content using CLT for braid OD (a) 5 mm, (b) 8 mm, (c) 10 mm______________________________________________ (a) 5 mm BFRP_____________________________________________ Layer Material Carriers OD Angle______________________________________________ 1 600 8 2.5 13 2 PET 32 3.8 11 3 PET 32 4.3 11 4 600 16 5.0 45_____________________________________________ 34.03 GPa_____________________________________________ φf 63.82 %___________________________________________________________________________________________ (b) 8 mm BFRP_____________________________________________ Layer Material Carriers OD Angle______________________________________________ 1 300 8 1.6 12 2 300 16 2.7 16 3 PET 32 3.5 10 4 600 16 4.5 25 5 600 16 5.2 26 6 PET 32 6.2 16 7 600 24 6.8 24 8 600 24 7.8 37_____________________________________________ 41.54 GPa_____________________________________________ φf 59.03 %___________________________________________________________________________________________ (c) 10 mm BFRP_____________________________________________ Layer Material Carriers OD Angle______________________________________________ 1 300 8 1.6 12 2 300 16 2.7 16 3 PET 32 3.5 10 4 600 16 4.3 42 5 600 16 5.2 41 6 PET 32 5.9 21 7 600 24 6.9 24 8 600 24 7.5 35 9 PET 24 8.6 39 10 600 24 9.2 31 11 600 24 9.9 38_____________________________________________ 40.96 GPa_____________________________________________ φf 57.50 %_____________________________________________ * Note: All values are an average of readings taken at several (10) * OD: Outer diameter (mm); Braid yarns: Basalt (tex), PET Monofilament; Angle (º)
  15. 15. Research Progress Sensitivity Analysis Sensitivity analysis on parameters affecting elastic modulus of braided rebars  Evaluations of fundamental processing parameters: TEX, Material modulus, Poisson’s ratio, Braiding angle  Influence of fibre & epoxy properties: 10% coefficient of variation  Monte Carlo approach using CLT analysis
  16. 16. Results The effect of braiding process is to reduce the variation arising from the material input properties
  17. 17. Conclusions  Direct relation between braiding parameters & rebar’s properties.  Pultruded FRP reinforcement Variation in input properties is directly reflected in rebar’s properties Braided FRP More complex situation due to interaction between the layers Further development of sensitivity analysis for braided BFRP rebars based on CLT numerical approach , using PSOM. Include braiding angle parameter, cost function & a heuristic approach for high quality designs.
  18. 18. THANK YOU! Training in Reducing Uncertainty in Structural Safety 2015 - 2018 sofia.antonopoulou@ucd.ie www.esr1truss.blogspot.com This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 642453.

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