RELIABILITY ASSESSMENT OF BRAIDED FRP REINFORCEMENT FOR CONCRETE STRUCTURES

Transcription

1 Training in Reducing Uncertainty in Structural Safety University College Dublin School of Civil Engineering RELIABILITY ASSESSMENT OF BRAIDED FRP REINFORCEMENT FOR CONCRETE STRUCTURES Sofia Antonopoulou & Ciaran McNally 27 th European Safety and Reliability Conference This project has received funding from the European Union s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No

2 Outline Background and Motivation General Research Idea Research Progress Results Conclusions

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 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 Background and Motivation Degradation mechanisms Moisture, Alkalinity, Temperature, Fatigue Durability of FRPs strongly dependent on Type of fibre & matrix Fibre content Fibre-matrix interface Orientation of fibres Limited information on FRP long-term durability in civil engineering applications Real, in-situ data are needed

6 Background and Motivation Manufacture methods of FRP: Pultrusion low cost & continuous process Braiding additional ductility & increased bond with concrete Design guidelines for the efficient use of FRPs in construction: ACI-440.1R CSA-S806-02

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 Background and Motivation Sensitivity analysis How design variables influence the optimisation cost function Braided FRP reinforcement Cost factor is related to geometrical & manufacturing parameters like braiding angle, number of layers, elastic modulus. Design Optimisation through Sensitivity Analysis Methods

9 General Research Idea Aim of the project: Design, Development, Optimisation & Performance Evaluation of Basalt Fibre Reinforced Polymer composites, for internal concrete reinforcement, using braiding as a manufacturing technique Main goal: Explore the potential of braided BFRP reinforcement in infrastructure applications

10 Research Progress Manufacturing design & process of braided BFRP preforms Materials Basalt fibres PET fibres Epoxy resin Material _ Property Basalt PET Epoxy resin Density (g/cm 3 ) Linear density (TEX) 300/ Yarn diameter (mm) 0.38/ Elastic modulus (GPa) 87/

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 Results Laboratory manufactured BFRP preforms & rebars using braiding & vacuum assisted resin infusion technique

13 Research Progress Classical Lamination Theory (CLT) numerical approach Numerical analysis 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 Results Direct relation between braiding parameters mm, (b) 8 mm, (c) 10 mm!!(9)! (a) 5 mm BFRP & rebar s properties mm, (b) 8 mm, (c) 10 mm!!(9)! Table 2. Technical braiding details - Numerically determined elastic moduli & fibre content using CLT for braid OD (a) 5 Table 2. Technical braiding details - Numerically determined _ elastic moduli & fibre content using CLT for braid OD (a) 5 Table _ Layer 2. Technical braiding details - Numerically determined _ Material Carriers OD Angle After the analysis on the mechanical properties of elastic (a) moduli & fibre content using CLT for braid OD (a) mm BFRP braided BFRP rebar, a sensitivity analysis!!(9)! is conducted the on analysis the parameters on the affecting mechanical cost properties as a function of (a) mm, Layer (b) 8 mm, (c) 10 mm _ 2 Material PET Carriers 32 OD 3.8 Angle 11 After 13 5 mm BFRP 600 PET (3) braided of elastic BFRP modulus. rebar, a sensitivity analysis is conducted After the on the analysis parameters on the affecting mechanical cost properties as a function of 3 PET Layer _ 24 Material PET 600 Carriers OD Angle Firstly, the influence of fundamental material properties elastic (TEX, BFRP modulus. materials rebar, a modulus, sensitivity Poisson s analysis ratio) is con- and φ GPa of braided 2 f PET % _ Firstly, ducted braiding on the parameters the influence of (braiding fundamental affecting angle) cost material as on a function rebar s prop PET GPa (b) erties of elastic (TEX, modulus. materials modulus, Poisson s ratio) and φ 8 mm BFRP modulus was determined. Then, all parameters were f % Layer braiding Firstly, ranked in the parameters order influence of influence of (braiding fundamental and angle) initial material on estimation rebar s properties (TEX, materials modulus, Poisson s ratio) and φ _ Material GPa Carriers OD Angle (b) 18 mm BFRP f (6) % modulus about the was most determined. important Then, parameters all parameters for optimization was obtained. were Layer ranked braiding in order parameters of influence (braiding and angle) initial estimation rebar s _ 2 Material 300 Carriers 16 OD 2.7 Angle 16 (b) 1 38 mm BFRP 300 PET about modulus the was most determined. important Then, parameters all parameters for optimization ranked was in obtained. order of influence and an initial estimation _ were Layer 2 4 Material Carriers OD Angle PET about 8! RESULTS the most AND important DISCUSSION parameters for optimization was obtained PET PET ! Braided RESULTS BFRP AND rebars DISCUSSION were designed and manufactured in three different sizes and configurations (5, GPa PET Braided 8! 8, RESULTS 10 mm BFRP diameter) AND rebars DISCUSSION while were changing designed key and parameters manufac- φ 6 f PET % _ tured (angle, in no three of layers) different to achieve sizes and the configurations desired structural (5, GPa (c) , Braided 10 mm BFRP diameter) rebars while were changing designed key and parameters manufac- φ 10 mm BFRP (10) geometry and meet the performance characteristics f % Layer (angle, tured of existing in no three of rebar layers) different reinforcement. to achieve sizes and the Manufactured configurations desired structural composites are then numerically analysed and the effect _ Material Carriers OD Angle (5, GPa (c) 10 mm BFRP geometry 8, 10 mm and diameter) meet the while performance changing key characteristics parameters φ f % Layer 2 Material 300 Carriers 16 OD 2.7 Angle 16 of (angle, of existing geometrical no of rebar layers) factors reinforcement. and achieve processing the Manufactured desired conditions structural composites geometry their elastic are and then properties meet numerically the is performance evaluated. analysed characteristics and the effect on _ (c) mm BFRP PET Layer 2 Material 300 Carriers 16 OD 2.7 Angle 16 of geometrical existing In Table rebar 2, technical factors reinforcement. and braiding processing Manufactured details conditions are illustrated along elastic are with then properties the numerically numerically is evaluated. analysed determined and the effective 6 PET composites on _ PET their of longitudinal In geometrical Table 2, in-plane technical factors modulus and braiding processing ( details ) using conditions are illustrated their proach along elastic and with properties Equations the numerically is 1 evaluated. 9, determined while Figure effective 4 a CLT ap on PET PET PET longitudinal braided In Table BFRP 2, in-plane technical preform modulus along braiding with ( details resin ) using are impregnated CLT illustrated rebars along in and with regular Equations the and numerically spiral 1 configuration 9, while determined Figure are effective shown. 4 a 611 PET approach PET braided longitudinal The values BFRP presented in-plane preform modulus are along calculated with ( resin ) using impregnated the CLT mean approach properties in and regular as Equations presented and spiral in 1 Table GPa rebars * OD: configuration 9, while 1. Outer diameter (mm); Braid yarns: Basalt (tex), PET Monofilament; Angle (º) in Figure are shown. 4 a φ9 11 PET f % The braided values BFRP presented preform are along calculated with resin using impregnated the mean * 10 Note: All values 600 GPa are an average 24 of readings 9.2 taken 31 at several

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 Results The effect of braiding process is to reduce the variation arising from the material input properties

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 THANK YOU! Training in Reducing Uncertainty in Structural Safety This project has received funding from the European Union s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No