Steel Free Hybrid Reinforcement System for Concrete Bridge Decks ...

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Fig. 4.7 Effect of embedment length on bond-slip curves ……………………. 90 Fig. 4.8 Effect of bar diameter on bond-slip curve ……………………………. 91 Fig. 4.9 Effect of polypropylene fibers on bond-slip curves (a) top – No.4 CFRP, (b) middle - No.4 GFRP and (c) bottom - No.8 GFRP ……. 92 Fig. 4.10 Failure for FRC and plain concrete specimens ……………………….. 93 Fig. 4.11 Residual slip versus numbers of fatigue cycles (a) top – No.4 CFRP, (b) middle - No.4 GFRP, and (c) bottom - No.8 GFRP……… 95 Fig. 4.12. Bond-slip response before and after fatigue loading (a) top - No.4 CFRP, and (b) bottom - No.8 GFRP………………………………… 96 Fig. 4.13. Degradation of bond stiffness ……………………………………….. 99 Fig. 4.14. Relationship between bond strength and splitting force ……………. 100 Fig. 4.15. Crack patterns in specimens showing effect of c b and v f ……………. 104 Fig. 4.16. Surface condition of FRP rebars after testing ………………………. 106 Fig. 4.17 Bond-slip relationship of various rebars in plain concrete and FRC (a) top - No.4 CFRP, (b) middle - No.4 GFRP, and (c) bottom - No.8 GFRP ………………………………………………… 110 Fig. 4.18. Previous definition of contribution from concrete …………………. 111 Fig. 4.19. Definition of splitting area for splitting-bond specimen …………… 113 Fig. 4.20 Static load-deflection response of specimens using No.4 CFRP reinforcement bars showing bond failure due to slip (Mode 1 failure) …. 116 Fig. 4.21 Static load-deflection response of specimens using No.8 GFRP reinforcement bars showing bond splitting failure (Mode 2 failure) ….. 116 Fig. 4.22 Schematic diagrams showing Mode 1 (top) and Mode 2 (bottom) failures …………………………………………….. 117 Fig. 4.23 Load-end-slip response of specimen reinforced with No.4 CFRP reinforcement ……………………………………………… 120 Fig. 4.24 Load – end-slip response of specimen reinforced with No.8 GFRP reinforcement ……………………………………………… 121 Fig. 4.25 Load-deflection response of specimen reinforced with No.4 CFRP reinforcement in a plain concrete (solid) and FRC (dashed) matrix …. 122 Fig. 4.26 Load-deflection response of specimen reinforced with No.4 GFRP reinforcement in a plain concrete (solid) and FRC (dashed) matrix …. 123 Fig. 4.27 Load-deflection response of specimen reinforced with No.8 GFRP reinforcement in a plain concrete (solid) and FRC (dashed) matrix … 123 Fig. 4.28 Load-deflection response of specimen reinforced with No.4 CFRP reinforcement in a plain concrete (bonded length = 10 db solid, bonded ………………………………………………………. 124 Fig. 4.29 Load-deflection response of specimen reinforced with No.4 GFRP reinforcement in a plain concrete (bonded length = 10 db solid, bonded length = 20 db dashed) ………………………………. 124 Fig. 4.30 Load-deflection response of specimen reinforced with No.8 GFRP reinforcement in a plain concrete (bonded length = 10 db solid, bonded length = 20 db dashed) ……………………………….. 125 Fig. 4.31 Slow-cycle load-deflection response after prescribed number of fast fatigue cycles (see inset legend) for the No. 8 GFRP reinforced specimens (plain concrete matrix). …………………….. 128 viii
Fig. 4.32 Fig. 4.33 Fig. 4.34 Fig. 4.35 Fig. 4.36 Fig. 4.37 Stiffness degradation computed from fast cycle fatigue test versus number of fatigue cycles for a No. 8 GFRP reinforced specimen (plain concrete matrix). ……………………………………. 128 Stiffness degradation computed from fast cycle fatigue test versus number of fatigue cycles for a No. 4 CFRP reinforced specimen (plain concrete matrix). …………………………………………….. 129 Influence of fibers in the fatigue performance of the No. 8 GFRP reinforced specimens. Substantial reduction in stiffness degradation with fatigue cycles is observed. …………………………. 130 Influence of fibers in the fatigue performance of the No. 4 CFRP reinforced specimens. …………………………………………….. 130 Load-deflection responses for no. 4 CFRP specimens in the post-fatigue static tests showing the influence of fibers. …………. 131 Stiffness degradation measured using CMOD and midspan deflection at two different upper limit fatigue load levels showing increased damage accumulation at the higher upper limit fatigue load ………………………………………….. 131 Fig. 5.1 Crack patterns for No.4 CFRP beams at moderate and high level loading …………………………………………………………. 136 Fig. 5.2 Crack patterns for No.4 GFRP beams at moderate and high level loading ………………………………………………………… 137 Fig. 5.3 Crack patterns for No. 8 GFRP beams at moderate and high level loading …………………………………………………………… 138 Fig. 5.4 Mechanism of crack formation in plain concrete and FRC beams …. 140 Fig. 5.5 Crack width versus applied moment of No.4 CFRP beams …………. 142 Fig. 5.6 Crack width versus applied moment of No.4 GFRP beams …………. 142 Fig. 5.7 Crack width versus applied moment of No.8 GFRP beams …………. 143 Fig. 5.8 Moment-deflection response for FRC beams ……………………….. 147 Fig. 5.9 Moment-deflection response for plain concrete beams ……… 148 Fig. 5.10 Moment-deflection response for No.4 CFRP with/without fibers ……. 148 Fig. 5.11 Moment-deflection response for No.4 GFRP with/without fibers …… 149 Fig. 5.12 Moment-deflection response for No.8 GFRP with/without fibers ……. 149 Fig. 5.13 Typical loading/unloading cycle’s effect on FRC beams ………… 152 Fig. 5.14 Typical loading/unloading response plain concrete beams ………. 152 Fig. 5.15 Typical strain distributions of No.4 CFRP beams ………………………. 153 Fig. 5.16 Typical strain distributions of No.4 GFRP beams …………………. 153 Fig. 5.17 Typical strain distributions of No.8 GFRP beams ……………….…… 154 Fig. 5.18 Typical failure modes ……………………………………………. 155 Fig. 5.19 Comparison of ultimate strain values of concrete ………………….. 157 Fig. 5.20 Energy-based ductility index (Naaman and Jeong, 1995) ………….. 158 Fig. 5.21 Typical moment curvature response for No.4 CFRP beams ………… 160 Fig. 5.22 Typical moment curvature response for No.4 GFRP beams ………… 160 Fig. 5.23 Typical moment curvature response for No.8 GFRP beams …………. 161 ix
Page 1 and 2: . . . . . . . . . . . . . . . . . .
Page 3 and 4: FINAL REPORT RI02-002 Steel-Free Hy
Page 5 and 6: EXECUTIVE SUMMARY New materials and
Page 7 and 8: 3.4.1 Flexural-Sensitive Beam Speci
Page 9: LIST OF FIGURES Fig. 2.1 Direct pul
Page 13 and 14: control as well as monitoring of th
Page 15 and 16: Table 8.1 Summary of Design Moments
Page 17 and 18: f GFRP allowable stress in the GFRP
Page 19 and 20: 1. INTRODUCTION 1.1. BACKGROUND AND
Page 21 and 22: continuous reinforcing bars, or com
Page 23 and 24: pitting of steel bars results from
Page 25 and 26: ehavior under different cover thick
Page 27 and 28: 2. BACKGROUND INFORMATION 2.1 BOND
Page 29 and 30: This test method has several disadv
Page 31 and 32: of the behavior of the FRP. A numbe
Page 33 and 34: applying tension to the reinforcing
Page 35 and 36: each of the two types of GFRP, alon
Page 37 and 38: second specimen was tested to 1,000
Page 39 and 40: of failure, bond strength can be ma
Page 41 and 42: The bar that had been exposed for 8
Page 43 and 44: modeled one-dimensionally. At the o
Page 45 and 46: The one bar-scale model presented b
Page 47 and 48: esistance to crack growth in the ha
Page 49 and 50: place forms made of concrete precas
Page 51 and 52: perpendicular to the main reinforce
Page 53 and 54: X = the distance in feet from load
Page 55 and 56: where A=effective tension area, in
Page 57 and 58: E=the effective length of slab resi
Page 59 and 60: d c = Dist. From extreme tension fi
Page 61 and 62:
The unfactored wheel loads placed o
Page 63 and 64:
The cover of the bottom of the cast
Page 65 and 66:
AASHTO AASHTO LFD LRFD MODOT NOTES
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2.4 DUCTILITY REALTED ISSUES FOR FR
Page 69 and 70:
Based on experimental data, Vijay a
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Figure 3.1 GFRP Tensile specimen wi
Page 73 and 74:
Two test configurations were used f
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correlation has been observed betwe
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3.3.1.2 Test Specimens Test specime
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This kind of specimen is not repres
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Figure 3.7 Casting operations for t
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Figure 3.9 Close-up photograph of m
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flexural beams were tested at UMC.
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Table 3.5 Flexural ductility test s
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Table 3.6 Experimental program for
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Data were recorded using a customiz
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thick and 1.5 in. wide stainless st
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The third slab used a hybrid reinfo
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Table 3.9 Reinforcement and spacing
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4. STATIC AND FATIGUE BOND TEST RES
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condition not exhibiting in real st
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u√f`c(MPa/√MPa) 3.2 2.8 2.4 2 1
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the loss of chemical bond, the curv
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of the embedded area had large bond
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Slip (in.) 0 0.2 0.4 0.6 0.8 1 1.2
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negligible mechanical bearing. Only
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were not in full contact because of
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specimens without fatigue loading,
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110.00% 100.00% 90.00% 80.00% 70.00
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approximated by f ct = 6. 8( f c '
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42 was obtained. As mentioned previ
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FRC Plain d) Crack patterns in #4 G
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4FC3 Pullout N/A 4FG1 Splitting 0.0
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I.D. Ultimate Bond Strength u (psi)
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4.3.2 Theoretical Prediction of Bon
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e be be le C (a) Schematic pullout
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By assuming the concrete strength o
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esponse until failure is initiated.
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the bond specimens with respect to
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typical load - end slip response fo
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18 Deflection (mm) 0 1 2 3 4 5 6 7
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14 12 Deflection (mm) 0 2 4 6 8 10
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4.4.2.3 Stiffness Degradation Speci
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110 Number of Cycles 0 20,000 40,00
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10 9 Deflection (mm) 0 1 2 3 4 5 6
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• Different bond mechanisms were
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index could be increased by as much
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0.4M u 0.8M u (a) VF4G (FRC beams)
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Table 5.1. Cracking moment and aver
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due to inadequate bond between the
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Moment (kN.m) 50 45 40 35 30 25 20
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As shown in Figures 5.5 through 5.7
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Specimen I.D. (1) Table 5.4. Compar
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m kN. ( n e Mom Deflection (in.) 0
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Based on the information provided b
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55 50 VP4C VP4C 450 45 400 40 VF4C
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Figure 5.18. Typical failure mode P
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Value used in this study Figure 5.1
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In the following sections, ductilit
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55 Curvature (1/in.) 0 0.0005 0.001
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6. ACCELERATED DURABILITY TEST RESU
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system, temperatures were varied fr
Page 185 and 186:
observation was made by Tannous and
Page 187 and 188:
6.3.1.2 Effect of environmental con
Page 189 and 190:
3 Slip (in.) 0 0.1 0.2 0.3 0.4 0.5
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1.4 1.2 Slip (in.) 0 0.1 0.2 0.3 0.
Page 193 and 194:
Slip (in.) 0 0.05 0.1 0.15 0.2 0.25
Page 195 and 196:
After specimens had been subjected
Page 197 and 198:
% Reduction of Design Bond Strength
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freezing-and-thawing cycles, damage
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Coated with Epoxy Solution Ingress
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ebar chairs were placed. This is ex
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concrete beams and from 4% to 8% fo
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55 50 Deflection (in.) 0 0.2 0.4 0.
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Table 6.3 Beam durability results f
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55 50 DP8G VP8G 450 45 40 DP8G 400
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Figure 6.31 Comparison of Ultimate
Page 215 and 216:
I.D. Table 6.7. Ductility index usi
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55 50 Curvature (1/in.) 0 0.0002 0.
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• With the addition of polypropyl
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shows the electronic test control f
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North Box Girder Support LVDT 1 Pot
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Figure 7.6 Stress contours on the u
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as these, it is not possible to eli
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potentiometers). The inset shows lo
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loops observed near zero load is ty
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GFRP/CFRP reinforced slab does as w
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More than a characteristic of the c
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Figures 7.18 and 7.19 show schemati
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profile of lower reinforcement mat)
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while a check of ultimate capacity
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Load Modifier The structure is duct
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(a) Truck Loads (multiple presence
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(d GFRP − c) ε GFRP = ε c , and
Page 249 and 250:
the transverse CFRP reinforcement o
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0.003 0.85 f’ c c a=β 1 c C ε C
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unrealistic based on results of ser
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parameters are identical to the one
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spacing of at least 10 in. in the t
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values. The bond specimens with a p
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• CFRP reinforced specimens exhib
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GFRP bars can be used exclusively f
Page 265 and 266:
ASTM C 1543-02, “Standard Test Me
Page 267 and 268:
CAN/CSA-S6-00, 2000, “Canadian Hi
Page 269 and 270:
Deflection,” Technical Report, De
Page 271 and 272:
Mashima, M., and Iwamoto, K., 1993,
Page 273 and 274:
Status of the Nation's Highways, Br
Page 275:
Table AI-3: Results From Compressio
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Steel Free Hybrid Reinforcement System for Concrete Bridge Decks ...

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