Lightweight Concrete for High Strength - Expanded Shale & Clay

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Strain (microstrains) 1400 1200 1000 800 600 400 200 0 0 5 10 15 20 25 30 35 40 45 Distance from End of Beam (in) Release 1 Day 3 Days 7 Days 14 Days Figure 5.10 Smoothed surface strain plot for East End of Girder G1C 1400 1200 Transfer Length = 28" 95% AMS Strain (microstrains) 1000 800 600 400 200 Initial Linear Trend Averaged, Smoothed Strain Profile Constant Strain Plateau 0 0 10 20 30 40 50 Distance from Girder End (in) Smoothed 14-Day CSS 95% AMS Initial Linear Trend Figure 5.11 Transfer Length Determined Using 95 Percent AMS Method for G1C-East 5-14
Table 5.5 –Transfer Length Results (inches) G1A G1B G1C G2A G2B G2C East West East West East West East West East West East West 19.5 18.75 25.00 18.75 28.00 21.50 17.50 13.25 13.00 13.00 19.00 18.00 FREE FREE FREE 5.7 Girder Tests and Results Each girder was loaded monotonically until failure at a load of approximately 400 kips. Loading proceeded in increments of approximately 30 kips or in deflection increments of about 0.25 inches. After each load or deflection increment, concrete surface strain (CSS) readings, deflection readings, crack spacings, and VWSG readings were recorded. Readings were also taken at special occurrences such as first flexural or shear crack observation or initial strand slip. Table 5.6 provides an overview of experimental results listing failure types, ultimate strain values and moments at cracking and ultimate conditions. The failure types were classified using the definitions below: FL - The girder failed by “BOTH” crushing of the deck and yielding of the strands. SH - The girder failed purely in shear. It did not meet the criteria for a flexural failure. SH/FL - The girder failed predominantly in shear, but still yielded the strands and crushed the deck. The two failure states occurred almost simultaneously. SH-SL - The girder underwent a shear failure initiated by the strands slipping. FL/SH-SL or SH-SL/FL - The girder underwent both failure modes with one occurring more predominantly than the other. Both failures would result in yielding of the strands and crushing of the deck. Although there are five failure types listed in Table 5.6, the failures fell into two major categories; flexural failures and shear failures. 5.7.1 Flexural Failures Figure 5.12 shows a photo of girder test G1-B West, a typical flexural failure. The vertical lines indicate the location of shear reinforcement. Flexural failures were ductile in nature. A typical flexural failure showed flexural cracks extending from the bottom of the girder up into the deck and evenly spaced shear cracks less than 0.02 inches in width between the 5-15
Page 1 and 2: School of Civil and Environmental E
Page 3 and 4: ACKNOWLEDGMENTS The research presen
Page 5 and 6: A statistical evaluation based on f
Page 7 and 8: 5.6 - Transfer Length 5-13 5.7 - Gi
Page 9 and 10: Report ACI 318- 99 AASHTO Standard
Page 11 and 12: Chapter 1. Introduction 1.1 Purpose
Page 13 and 14: Long term properties including pret
Page 15 and 16: ottom flange. Prestressing strands
Page 17 and 18: 12500 12000 Concrete Strength, fc'
Page 19 and 20: Chapter 3. Mix Designs, Field Evalu
Page 21 and 22: Variation of coarse-to-fine aggrega
Page 23 and 24: 3.2.1 Compressive Strength Figure 3
Page 25 and 26: Table 3.5 Chloride Permeability --
Page 27 and 28: 12,000 11,500 11,000 Compressive St
Page 29 and 30: 1,400 1,300 1,200 1,100 Experimenta
Page 31 and 32: strength (10L made in the laborator
Page 33 and 34: The 50% and 90% of the 620-day cree
Page 35 and 36: 700 600 10,000-psi Measured Shams &
Page 37 and 38: a Creep Coefficient 3.0 2.5 2.0 1.5
Page 39 and 40: Chapter 5. Behavior of AASHTO Type
Page 41 and 42: Portion of Girder Damaged During Te
Page 43 and 44: 2” End Cover (Typ both ends) 4 Sp
Page 45 and 46: 5.3 Instrumentation The surface of
Page 47 and 48: Figure 5.7 Installation of stirrups
Page 49 and 50: Table 5.3 Girder concrete propertie
Page 51: 120 100 80 Stress (ksi) 60 40 20 0
Page 55 and 56: Figure 5.12 Typical flexural failur
Page 57 and 58: Since G2 girders had a higher concr
Page 59 and 60: V " pc cw− Pr ed = ft −Pr ed 1
Page 61 and 62: Test # Table 5.9 Predicted vs. Expe
Page 63 and 64: this research project, modification
Page 65 and 66: Chapter 6. Prestress Losses in HPLC
Page 67 and 68: losses in the 10,000-psi girders to
Page 69 and 70: Microstrains (in/inx10 -6 ) 0 500 1
Page 71 and 72: 6.3 Conclusions Regarding Prestress
Page 73 and 74: 7.3 Transfer Length An evaluation o
Page 75 and 76: Shrinkage after 620 days of drying
Page 77 and 78: More research is required to examin
Page 79 and 80: Appendix A. Background A.1 Introduc
Page 81 and 82: Raithby and Lydon described the use
Page 83 and 84: are normally recognized as being on
Page 85 and 86: aggregate must be saturated by pres
Page 87 and 88: A.7.2 Strength Ceiling Harmon discu
Page 89 and 90: compared to lower strength specimen
Page 91 and 92: A.8.8 Deatherage, Burdette and Chew
Page 93 and 94: 3. Concrete compressive strength at
Page 95 and 96: findings were comments that the AAS
Page 97 and 98: including strand diameter, embedmen
Page 99 and 100: l d = l t + l fb = f si 3 d b + 1.5
Page 101 and 102: l d = l t + l fb ⎛ = ⎜ ⎝ f d
Page 103 and 104:
Table A.1 Summary of Development Le
Page 105 and 106:
strand release, the strand attempts
Page 107 and 108:
Appendix B. Creep and Shrinkage B.1
Page 109 and 110:
Changes in moisture migration: the
Page 111 and 112:
t′: age of concrete at loading (d
Page 113 and 114:
s: slump (in) γ ψ ⎧ 0.30 −1.4
Page 115 and 116:
t: age of concrete (days) t 0 : age
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where ε sh ∞ ⎧ 510 µε for st
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left girder-end. The dimension L wa
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6” 85” 50” Segment of girder
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146” 89” 96” 137” Stirrups
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were added in a specific sequence f
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C.2.3 Formwork Removal, Detensionin
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Figure C.19 Mostafa Prestressing St
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Figure C.22 Ms. Lyn Clements (GDOT)
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If significant strand end slip over
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CSS at Level of Bottom Strands (µ
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Appendix D. Prestress Losses in HPL
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E ps : elastic modulus of prestress
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D.2.2. AASHTO-LRFD Refined Estimate
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∆f log(24 ⋅t) ⎛ f ⎜ ⎞ 55
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P i : initial prestressing force af
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References AASHTO (1996), Standard
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ASTM C 618, Standard Specification
Page 151 and 152:
Guide for Structural Lightweight Ag
Page 153 and 154:
Martin, L. D., Scott, N. L., “Dev
Page 155:
Shahawy, M. A., Batchelor, B., “S
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Lightweight Concrete for High Strength - Expanded Shale & Clay

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