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

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6.4 Concluding Remarks …………………………..…………………………….. 199 7. Full Scale Slab Tests ……………………………………………………………… 202 7.1 7.2 Test Program and Associated Test Protocols ………………………………… 202 Loading Used for Static and Fatigue Tests …………………………………… 206 7.3 Test Results and Discussions ………………………………………………. 208 7.3.1 Concrete Slab Properties …………………………………………….... 208 7.3.2 Reinforcing Bar Properties …..……….……………………………….. 208 7.3.3 Virgin Static and Slow Cycle Fatigue Tests …..……….…………….. 208 7.3.4 Fatigue Tests …………………………...………………………….... 214 7.3.5 Post-Fatigue Static Tests …..…………………………….…………….. 216 7.3.6 Cracking Patterns and Failure …..……………………….…………….. 217 7.4 Summary Observations ………………………………………………………. 220 8. Design Example of Hybrid FRP Reinforced Bridge Deck Slabs ………………..… 222 8.1 Introduction ………………………………………………..………………… 222 8.2 Statement of the Design Problem …………………………….…………… 223 8.3 Loadings and Design Moments ………………………………………………. 223 8.3.1 Loading Considerations 8.3.2 Design Moment Envelope …………………………………………….... 223 …..……….……………………………….. 225 8.4 Working Stress Design …………..…………………………………………. 228 8.5 Failure Mode at Ultimate Capacity …………………………………………. 232 8.6 Crack Widths …………………………………………………………………. 235 8.7 8.8 Creep Rupture and Fatigue ……………………………………………………. 237 Shear ……………………………………..……………………………………. 237 8.9 Temperature and Shrinkage Reinforcement ………………………………. 238 9. Conclusions and Recommendations ……………………………………………… 240 9.1 Conclusions ………………………………………………………………. 240 9.1.1 Bond Tests 9.1.2 Flexural Tests 9.1.3 Durability Tests ……………………………………………………….... 240 …..……….……………………..……………….. 241 ……………………………………………………. 242 9.1.4 Full-Scale Slab Tests ……………………………………………… 243 9.2 Recommendations …………………………………………………………. 244 References Appendix I ………………………………………………………………………… 246 ………………………………………………………………………….. 256 vi
LIST OF FIGURES Fig. 2.1 Direct pullout test ……………………………………………………. 10 Fig. 2.2 Flexural bond test …………………………………………………… 12 Fig. 2.3 Cantilever test …………………………………………………………. 12 Fig. 2.4 Bridge deck slab reinforcement systems (a) early Canadian steel-free deck slabs, (b) arch action in reinforced concrete beam, (c) layered hybrid composite system, and (d) continuous/discrete hybrid reinforcement system …………………………………………. 29 Fig. 2.5 FRP panels, FRP bars and FRP grid used in Wisconsin …………….. 31 Fig. 2.6 Reinforcement details …………………………………………… 40 Fig. 2.7 Definition of ductility index (Naaman and Jeong, 1995) ………… 50 Fig. 3.1 GFRP tensile specimen with bonded steel tubes for gripping ……….. 53 Fig. 3.2 CFRP tensile specimen in the test fixture showing gripping and displacement measurement details ……………………………….. 53 Fig. 3.3 Overall view (left) and a close-up view of the closed-loop compression test ………………………………………………………. 55 Fig. 3.4 Compression test on standard 6 in. diameter cylinders …… …… ……… 56 Fig. 3.5. Pull-out specimens …………………………………………………….. 58 Fig. 3.6. Splitting bond specimen configuration ……………………………….. 60 Fig. 3.7 Casting operations for the flexural bond specimens …… ……… ………. 63 Fig. 3.8 Schematic of the flexural bond specimen ………………………………. 63 Fig.3.9 Close-up photograph of midspan deflection and CMOD LVDTs ……… 65 Fig. 3.10 Close-up photograph of end-slip LVDT ………………………………. 65 Fig. 3.11 Test setup used for the flexural bond test …………………………….. 66 Fig. 3.12. Beam details …………………………… ……………………………… 69 Fig. 3.13 Geometric details of the shear-sensitive beam (Type 3 beam) ………… 72 Fig. 3.14 Set-up showing Type 3 beam in the test fixture ……………………….. 72 Fig. 3.15 The conventional deck slab with steel reinforcement ready for Fig. 3.16 plain concrete matrix placement ……………………………………….. The all-GFRP second deck slab is ready for FRC matrix placement …… 76 76 Fig. 3.17 The CFRP/GFRP hybrid deck slab is ready for FRC matrix placement… . 77 Fig. 3.18 Schematic plan view of the deck slab test configuration ………………. 78 Fig. 3.19 Schematic side elevation of the deck slab test configuration …………. 78 Fig. 3.20 Fabrication of the conventionally reinforced slab (a) concrete consolidation, and (b) concrete finishing operations ………………….. 79 Fig. 4.1 Bond mechanisms for deformed GFRP rebar (Hamad, 1995) ……. 81 Fig. 4.2. Average bond and local bond ……………………………………….. 81 Fig. 4.3. Bond-slip relationship of GFRP and CFRP specimens ……………… 85 Fig. 4.4 Surface conditions of rebars (left before and right after test in each case) …………………………………………………….. 86 Fig. 4.5 Idealized load-slip curve for CFRP rebar embedded in concrete …………………………………………………………….. 86 Fig. 4.6 Deformation patterns available in FRP rebars ………………………. 88 vii
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: 3.4.1 Flexural-Sensitive Beam Speci
Page 11 and 12: Fig. 4.32 Fig. 4.33 Fig. 4.34 Fig.
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
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d c = Dist. From extreme tension fi
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The unfactored wheel loads placed o
Page 63 and 64:
The cover of the bottom of the cast
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AASHTO AASHTO LFD LRFD MODOT NOTES
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2.4 DUCTILITY REALTED ISSUES FOR FR
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Based on experimental data, Vijay a
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Figure 3.1 GFRP Tensile specimen wi
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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
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observation was made by Tannous and
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6.3.1.2 Effect of environmental con
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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.
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Slip (in.) 0 0.05 0.1 0.15 0.2 0.25
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After specimens had been subjected
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% 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
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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
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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
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ASTM C 1543-02, “Standard Test Me
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CAN/CSA-S6-00, 2000, “Canadian Hi
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Deflection,” Technical Report, De
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Mashima, M., and Iwamoto, K., 1993,
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Status of the Nation's Highways, Br
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Table AI-3: Results From Compressio
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Steel Free Hybrid Reinforcement System for Concrete Bridge Decks ...

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