Bai ging vt liu FRP references

An Introduction to FRP-Reinforced Concrete Source Design with FRP reinforcement Module Objectives • To introduce students to the general philosophies and procedures for designing concrete structures with FRP reinforcement ISIS EC Module Design with FRP Introduction reinforcement Section: • A primary factor leading to extensive degradation… Corrosion Concrete Reinforcing Steel Moisture, oxygen and chlorides penetrate Through concrete Through cracks Corrosion products form Volume expansion occurs More cracking Corrosion propagation ISIS EC Module End result Design with FRP reinforcement Introduction Section: • Advantages Lightweight High Strength Easy to handle 5x steel FRP Materials Corrosion resistant Highly versatile Suit any project Durable structures ISIS EC Module Design with FRP reinforcement FRP Materials Section: General • Wide range of FRP products available: Fibres along axis • Unidirectional bars • Orthogonal grids Unidirectional bars in two directions • Prestressing tendons ISIS EC Module Design with FRP reinforcement FRP Materials Section: General Unidirectional glass FRP bar Glass FRP grid Carbon FRP prestressing tendon Glass fibre roving Carbon fibre roving ISIS EC Module Design with FRP FRP Materials reinforcement Section: Constituents • What is FRP? Fibres Matrix Provide strength and stiffness Protects and transfers load between fibres Carbon, glass, aramid Fibre Epoxy, vinyl ester Composite Matrix Creates a material with attributes superior to either component alone! ISIS EC Module Design with FRP reinforcement FRP Materials Section: Manufacturing • To enhance FRP bar’s mechanical bond with concrete: Incorporate sand on the surface… ISIS EC Module …or a fibre braid Design with FRP reinforcement FRP Materials Section: Properties ISIS EC Module 2500 Stress [MPa] • FRP properties (versus steel): • Linear elastic behaviour to failure • No yielding • Higher ultimate strength • Lower strain at failure 2000 1500 CFRP GFRP 1000 Steel 500 Strain [%] Design with FRP reinforcement FRP Materials Section: Properties FRP material properties are a function of: Type of fibre and matrix Fibre volume content Orientation of fibres ISIS EC Module Design with FRP Spacing and Cover reinforcement Section: Concrete Cover • Adequate cover required to: db Prevent cracking due to thermal expansion Prevent swelling from moisture ingress Protect reinforcement from fire Exposure Beams Slabs Interior 2.5db or 40 mm 2.5db or 20 mm Exterior 2.5db or 50 mm 2.5db or 30 mm ISIS EC Module Cover Design with FRP Spacing and Cover reinforcement Section: Bar Spacing • Adequate bar spacing required to: Allow for easy placement of concrete Prevent temperature cracking Minimum “s” 1.4 db Maximum “s” 1.4max aggregate size 5hslab 30 mm 500 mm concrete cover ISIS EC Module s Design with FRP reinforcement Spacing and Cover Section: Constructability • When designing with FRPs: Protect FRPs against UV radiation Store and handle each FRP product carefully Avoid contact between carbon FRPs and steel (galvanic corrosion) Tie FRP bars to formwork (with plastic ties) to prevent floating during concrete pour Avoid damaging FRP bars during concrete vibration by using a plastic protected vibrator ISIS EC Module Design with FRP Additional Topics reinforcement Section: Development Length and Anchorage • Development length of FRP bars depends on: Bar diameter Differs depending on FRP type Bar shape Surface condition Check manufacturer specifications Embedment length ld ld ISIS EC Module Design with FRP reinforcement Additional Topics Section: Flexural Design Aids • Flexural design aids are available What: Series of charts to aid in design of rectangular sections with 1-layer of reinforcement Where: In Chapter 10 of ISIS Design Manual No Why: Use of charts will satisfy both serviceability and ultimate limit states requirements ISIS EC Module Design with FRP reinforcement Additional Topics Section: Shear Design • FRP as shear reinforcement has successfully been used in field applications ISIS EC Module Design with FRP reinforcement Case Studies Section: Taylor Bridge Bridge during construction ISIS EC Module Design with FRP reinforcement Case Studies Section: Taylor Bridge Placement of the deck slab concrete ISIS EC Module Design with FRP Case Studies reinforcement Joffre Bridge Sherbrooke, Quebec Re-opened 1997 30.6 metre span 25 000 vehicles daily ISIS EC Module Section: Design with FRP reinforcement Case Studies Section: Joffre Bridge Flexural reinforcement Portions reinforced with carbon FRPs u v uBarrier Wall vSidewalk wDeck ISIS EC Module w Design with FRP reinforcement Case Studies Placement of instrumented carbon FRP deck reinforcement grids ISIS EC Module Section: Joffre Bridge Design with FRP Case Studies reinforcement Wotton bridge Wotton, Quebec Re-opened 2001 30.6 metre span ISOROD GFRP & CFRP in deck slab ISIS EC Module Section: Design with FRP reinforcement Case Studies Section: Wotton Bridge Placement of glass FRP deck reinforcement ISIS EC Module Design with FRP Case Studies reinforcement Morristown Bridge Morristown, Vermont Re-opened 2002 43 metre span ISOROD GFRP in deck slab FRP bridge deck reinforcement ISIS EC Module Section: Design with FRP reinforcement Case Studies GFRP reinforcement for the deck slab just prior to placing the concrete ISIS EC Module Section: Morristown Bridge ... desirable: sufficient warning rfrp < rbal rfrp = rbal rfrp > rbal efrp = efrpu efrp = efrpu efrp < efrpu ec < ecu ec = ecu ISIS EC Module ec = ecu Design with FRP Design for Flexure reinforcement 0.85f’c... Equilibrium T=C ΦfrpefrpuEfrpAfrp Eq 3-3 Eq 3-7 Φca1f’cb1cb Eq 3-8 ISIS EC Module Design with FRP reinforcement Design for Flexure Section: • When rfrp > rfrpb Compression failure • When rfrp < rfrpb Tension... 0.003 FRP: efrp < efrpu ISIS EC Module Design with FRP Design for Flexure reinforcement Section: Compression Failure a1Φcf’c ecu b a = b1c c C d Afrpb efrp Cross Section Strain Distribution Φfrpffrp