Lightweight Concrete for High Strength - Expanded Shale & Clay

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Table 5.10 Predicted vs. Experimental V u Values for Tests Failing in Shear Test # AASHTO Standard f y = 62 ksi V u (kips) AASHTO Standard f y = 60 ksi V u (kips) AASHTO LRFD f y = 62 ksi V u (kips) Exp. V u Percent Diff. Exp vs Std 62 Percent Diff. Exp vs Std 60 Percent Diff. Exp vs LRFD (kips) G1A-Center 138.7 137.4 103.8 258.0 86.0% 87.8% 148.5% G1B-East 243.3 238.9 241.1 312.2 28.3% 30.7% 29.5% G1B-Center 138.6 137.3 104.3 234.1 68.9% 70.5% 124.5% G1C-East 238.4 234.0 255.5 289.2 21.3% 23.6% 13.2% G2A-Center 149.5 148.2 82.3 255.9 71.2% 72.7% 211.0% G2B-Center 150.9 149.6 102.7 246.3 63.2% 64.6% 139.9% G1 Average 51.1% 53.2% 78.9% G2 Average 67.2% 68.7% 175.5% G1 Std Dev 31.3% 31.0% 67.5% G2 Std Dev 5.7% 5.7% 50.3% The current AASHTO Standard specification provides a conservative prediction of concrete and ultimate shear capacity when shear steel capacity is capped at a yield strength of 60 ksi. The alternate design procedure listed in ACI-318 Section 11.4.2.2 for predicting shear strength produced some unconservative predictions for concrete compressive strengths over 10,000 psi. The method for predicting interface shear strength is conservative for HSLC. The current AASHTO LRFD specification provides a conservative prediction of ultimate strength. 5.10 Development Length of 0.6-in. Strand in HPLC Table 5.11 presents the development length test results. An evaluation of current code provisions using the twelve slate HPLC girder development length tests in this study and eight normal weight HPC girder tests from Dill (2000) showed the current AASHTO (1996) and ACI provisions to be conservative (Table 5.12). The code equations overestimated development lengths by 19 percent for both slate HPLC and normal weight HPC and never underestimated them. Use of the current code provisions for design of development length for slate HPLC and 0.6-inch diameter strand was conservative. Based on the concrete strength range addressed in 5-24
this research project, modification of the current code specifications for development length was not necessary for HPLC or for 0.6-inch diameter strands. Test # E=East W=West Stirrup Density 1X 2X Table 5.11 Development Length Test Results Strand Embedment Average Strand Slip at P max (inches) Maximum Strand Strain ε ps (in/in) Maximum Deck Strain ε cu (in/in) Failure Mode FL-Flexure SH-Shear SL-Strand Slip (inches) G1A-E 2X 67 0.0102 0.0158 0.0038 FL/SH-SL G1A-W 1X 96 0.0000 0.0168 0.0042 FL G1B-E 1X 67 0.7350 0.0078 0.0030 SH-SL G1B-W 2X 81 0.0007 0.0190 0.0032 FL G1C-E 1X 81 0.1988 0.0113 0.0032 SH-SL/FL G1C-W 1X 91 0.0000 0.0140 0.0036 FL G2A-E 2X 67 0.0033 0.0190 0.0036 FL G2A-W 1X 96 0.0000 0.0204 0.0072 FL G2B-E 1X 67 0.0065 0.0155 0.0045 FL G2B-W 2X 81 0.0000 0.0199 0.0064 FL G2C-E 1X 81 0.0041 0.0228 0.0045 FL G2C-W 1X 91 0.0000 0.0198 0.0049 FL Basis of Comparison Table 5.12 Proposed Equation Evaluation for use on HPLC AASHTO ACI Code Proposed Equation For Design 5000 ⎞ + f ps − fse d ' f Proposed Equation For Best Fit 2500 f ps fse d f ⎟ ⎞ 50 + − ' ci ⎠ ⎛ 2 ( f ps − 3 f se ) d ⎜ b ⎟ ⎛ ⎜ ⎝ ⎠ ⎝ Avg Diff (HSLC) 19% 13% 4% Max Over (HSLC) 30% 31% 21% Max Under (HSLC) 8% 2% -6% 50 b ⎜ b ci Avg Diff (NWC) 18% 2% -5% Max Over (NWC) 18% 4% -3% Max Under (NWC) 17% 0% -6% Avg Diff (Overall) 19% 9% 1% Max Over (Overall) 30% 31% 21% Max Under (Overall) 8% 0% -6% 5-25
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School of Civil and Environmental E
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ACKNOWLEDGMENTS The research presen
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A statistical evaluation based on f
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5.6 - Transfer Length 5-13 5.7 - Gi
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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 and 52: 120 100 80 Stress (ksi) 60 40 20 0
Page 53 and 54: Table 5.5 -Transfer Length Results
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: Test # Table 5.9 Predicted vs. Expe
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
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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
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Guide for Structural Lightweight Ag
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Martin, L. D., Scott, N. L., “Dev
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Shahawy, M. A., Batchelor, B., “S
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Lightweight Concrete for High Strength - Expanded Shale & Clay

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