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Table 2 Column index, concrete strength, steel/fiber reinforcement ratios and fiber wrapping scheme.

From: Seismic Retrofitting of RC Circular Columns Using Carbon Fiber, Glass Fiber, or Ductile PET Fiber

TG Specimen index fcu MPa ρst % ρtie % ρf % Fiber type # of layers Method of application [Area of fiber (mm2/pitch)]
1 C-1-Control 21.0 1.93 0.37
C-1-CF 0.108 CF 1 CF sheet (27.23)
C-1-PET 1.05 PET 20 PET sheet (262.5)
2 C-2-Control 30.8 1.93 0.37
C-2-GF 0.108 GF 1 GF sheet (106)
C-2-PET 1.05 PET 10 PET sheet (132)
3 C-3-Control 41.1 1.83 0.29
C-3-PET 1.31 PET 25 PET sheet (393.8)
C-3-HF-hoop 1.32 HF 1 HF strand, hoop (PET = 362.4&AF = 32.7)
C-3-HF-spiral 1.32 HF 1 HF strand, spiral (PET = 362.4&AF = 32.7)
C-3-HF-spiral-LS 1.32 HF 1 HF strand, spiral-LS (PET = 362.4&AF = 32.7)
  1. LS is lap-splice (equal to 1.3 times development length); fcu is compressive strength of concrete at 56 days; ρst is steel reinforcement ratio (Ast/Ag); Ast is area of steel; Ag is gross area of specimen; ρtie; = tie reinforcement ratio (Vtie/Vcore_con); Vtie is volume of column tie; Vcore_con is volume of core concrete; ρf = fiber reinforcement ratio (Vf/Vcore_con); Vf is volume of fiber (= area of fiber (mm2/pitch) × perimeter × pitch (1 pitch is 250 mm and 300 mm for TG-1 & TG-2 and TG-3, respectively; shear span(a) is 1,200 mm and 1250 mm for TG-1&TG-2 and TG-3, respectively; effective depth (d) is 352 mm for all columns; a/d = 3.4 and 3.5 for TG-1&TG-2 and TG-3, respectively; column diameter = 400 mm and column height = 1500 mm for all columns.