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

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T CFRP T GFRP u u ’ u 0.002 u 0.01 u design u b,f u b,s u test u theo. w V f α β β d ∆ mid ε CFRP ε cu ε GFRP tensile force in the CFRP reinforcement tensile force in the GFRP reinforcement bond strength (longitudinal component of R), psi bond strength at second peak, psi bond strength at the slip of 0.002 in. at the free end, psi bond strength at the slip of 0.01 in. at the loaded end, psi design bond strength , psi bond strength of FRP rebar to concrete, psi bond strength of steel rebar to concrete, psi bond strength based on test results, psi theoretical bond strength, psi crack width at tensile face of the beam, in. volume fraction of fibers rib angle coefficient to converse crack width corresponding to the level of reinforcement to the tensile face of beam modification factor for FRP reinforced beam mid-span deflection, in. elastic stress in the CFRP reinforcement ultimate concrete strain elastic stress in the GFRP reinforcement ψ ε=0.001 curvature at concrete strain of 0.001 ψ u γ curvature at ultimate adjustment factor for different embedment length µ friction coefficient µ Ε ductility index ρ f ρ fb reinforcing ratio of FRP reinforced concrete balanced reinforcing ratio of FRP reinforced concrete xvi
1. INTRODUCTION 1.1. BACKGROUND AND PROJECT OVERVIEW There are approximately 592,000 bridges in the United States. Of this total, approximately 78,000 bridges are classified as structural deficient, 80,000 bridges are functionally obsolete (FHWA 2003). These numbers indicate that in excess of 25 percent of the bridges listed in the National Bridge Inventory Databases are in need of repair or replacement. Steel reinforcement corrosion is the primary reason for the structural deficiency of reinforced concrete (RC) bridges. The annual direct cost of corrosion for highway bridges is estimated to be $8.3 billion, consisting of $3.8 billion to replace structurally deficient bridges over the next ten years, $2.0 billion for maintenance and cost of capital for concrete bridge decks, $2.0 billion for maintenance and cost of capital for concrete substructures (minus decks), and $0.5 billion for maintenance painting of steel bridges. Life-cycle analysis estimates indirect costs to the user due to traffic delays and lost productivity at more than ten times the direct cost of corrosion maintenance, repair, and rehabilitation. (CorrosionCost.com 2004). Limited service life and high maintenance costs are associated with corrosion, fatigue and other degradation of highway bridges and RC structures. Corrosion problems began to appear in steel reinforced concrete in the 1960s. De-icing salt used in colder climates, and associated chloride penetration is a major cause of this corrosion in highway structures. Expansion, cracking, and eventual spalling of the concrete cover are the results of salt-related damage. Additionally, loss of bond between steel and concrete also occurs, resulting in structural damage to RC members. The long-term integrity of RC structures is of major concern. Repair and/or replacement of deteriorating structures constitute an enormous task that involves prohibitively high cost. For example, in the state of Missouri 10,533 bridges are classified as deficient (corrosion.com 2004), which amounts to 46% of its total number of bridges. In the late 1970s, the Federal Highway Administration (FHWA) funded extensive research to probe into various ways of overcoming this problem. 1
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 and 10: LIST OF FIGURES Fig. 2.1 Direct pul
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: f GFRP allowable stress in the GFRP
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
Page 67 and 68: 2.4 DUCTILITY REALTED ISSUES FOR FR
Page 69 and 70:
Based on experimental data, Vijay a
Page 71 and 72:
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
Page 91 and 92:
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
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
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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
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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