Fiber Reinforced Plastics PDF

18/03/62 CVE236 Civil Engineering Materials Fiber Reinforced Plastics Dr. Raktipong SAHAMITMONGKOL [email protected] 1 Fiber Reinfo...

18/03/62 CVE236 Civil Engineering Materials Fiber Reinforced Plastics Dr. Raktipong SAHAMITMONGKOL [email protected] 1 Fiber Reinforced Plastics (FRP) Another type of composite materials which is strong under tension Consists of very high strength fibers embedded in epoxy matrix Appropriate for flat and large round surfaces at least 1 direction Uniaxial fibers embedded into polymer matrix, (Courtesy SIKA/EMPA). 2 1  18/03/62 FRP: Properties of Fibers Relative Thickness of Fibers Glass fiber Glass Fiber Tensile Stress Strain AramidFiber Aramid fiber Relationship Carbon Fiber carbon - highest strength carbon fiber Carbon HumanHair Human hair 4000 Tensile Stress (MPa) Aramid 2000 Glass can deform more than tensile stress 0.000 0.020 0.040 Tensile Strain 3 Introduction of FRP Composite Materials CFRP vs Steel Reinforcement 4000 Carbon Fiber fiber is very strong Brittle Tensile Stress (MPa) Gr. 270 Strand 2000 fiber + prastic CFRP Gr. 60 Rebar + Ductile 0.00 0.020 0.040 Tensile Strain 4 Introduction of FRP Composite Materials 2  18/03/62 FRP Bars AFRP CFRP 13.7 mm 8 mm Diameter 5 high ability to craay the load but has a light weight FRP for External Bonding (Strengthening) Pre-cured Strips Hand-Lay-Up without prastic (FRP Laminates) (FRP Sheets) Sika MITSUBISHI, & Sika can put it on the concrete put the epoxy first then put the FRP it will help the structure carry the load sheet then cover it with epoxy again6 Introduction of FRP Composite Materials used to strength the smooth surface and stress structure. 3  18/03/62 FRP Strengthening: Advantage & Limitation Advantages: Lightweight and thin (space-saving) Good bonding High stiffness and ultimate tensile strength Non-corrosive nature Limitations: Brittle - เวลาพัง จะพังแล้วพังเลย Comparatively higher cost Susceptible to degradation by UV or moisture Low fire resistance (Tg of 70 to 80 oC) น้อนละลาย 7 Flexural FRP Strengthening Uniaxial FRP Composite strip/sheet Straight FRP sheet. we put it in the tension side(?) Uniaxial FRP Composite strip/sheet direction -> follow the stress 8 4  18/03/62 Shear Strengthening by FRP the best apply Complete Wrap U-Wrap Two-sides 9 Use ofDesign FRP Composite for Shear of RC Shear Strengthening Strengthening Beam Shear Strengthening by FRP: Configurations Strips put near the support put in the vertical direction for the shear force Continuous Bi-axial 10 5  18/03/62 Shear Strengthening of Circular Column FRP ทําให้คอลัมไม่อ้วน (a) Severely deteriorated circular column (b) FRP repaired circular column not use in vertical direction 11 Use of FRP Composite for Column Strengthening Effect of Lateral Confinement on Compressive Behavior Circular Column Stress Confined concrete Unconfined concrete Stress Confined concrete Strain Slightly cracked confined concrete Severely cracked confined concrete Unconfined concrete Cracked unconfined concrete Strain 12 6  18/03/62 put the proxy and FRP in the concrete Put FRP on the surface - concrete protect the FRP (น้องบอบบางต่อความชี้น ไฟ แดด) External Bonding vs Near-Surface Mounting concrete concrete EB adhesive NSM groove-filler FRP plate or sheet FRP bar Advantages of NSM Technique Better in protection the strengthening material from external damage. The amount of site installation work may be reduced, as no surface preparation is required apart from the grooving. Less prone to debonding from the concrete substrate. The aesthetics of the strengthened structure is virtually unchanged. 7