Lightweight Concrete for High Strength - Expanded Shale & Clay

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5.2 Girder Design Three each Series G1 girders and three each Series G2 girders were designed with concrete design strengths, f c ’, of 8,000 psi and 10,000 psi, respectively. Based on previous experiences, it was assumed the girder lengths would be in the range of 35-45 feet. Final design lengths were revised to accommodate the tests as needed. Three tests were planned for each of the six girders indicating 18 total tests. Since two concrete strengths were being investigated, there were 9 different test configurations that were performed on each series of girders. The prestressed girder design spreadsheet was used to iteratively design the tests to fit on the girders. The resulting tests were detailed in Table 5.1. The a/d ratio listed under “Point Load Placement Criteria” is the shear span to depth ratio where “d” is the total height of the composite girder. Test Configuration Stirrup Density Table 5.1 – Girder Test Configurations Point Load Placement Criteria Shear Span “a” (inches) Distance “L 1 ” Distance “L 2 ” Distance “L” (inches) (inches) (inches) 1 Single l d 90 456 0 456 2 Double 0.70*l d 61 316 0 456 3 Double 0.85*l d 75 456 0 456 4 Single 0.95*l d 85 504 0 504 5 Single 0.70*l d 61 321 0 456 6 Single 0.85*l d 75 369 0 504 7 Minimum a/d=2.28 82 185 140 456 8 Minimum a/d=2.67 96 210 135 456 9 Minimum a/d=3.33 120 244 135 504 d = 47.5 inches The dimension “a” was the shear span. The dimension L 1 was the distance from the left support to the right support. The dimension L 2 was the distance from the left COB (cent of bearing) to the left support. The COB was the point at a distance of 6 inches in from each girderend that was assumed to be the girder’s support point for curing. L 2 was used to signify a cantilever on the left girder-end. The dimension L was the distance from the left COB to the right COB. The dimensions “a,” L 1 , L 2 and L are shown in Figure 5.1. Figures 5.2 through 5.4 show the final designs of the six girders. 5-2
Portion of Girder Damaged During Test # 1 Test # 1 on Composite Girder Portion of Girder Damaged During Test # 2 Test # 2 on Composite Girder a Center Of Bearing Center Of Bearing 6 in. L 2 L 1 L 6 in. Test # 3 on Composite Girder Figure 5.1 Concept of Girder Testing Sequence 5-3
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: Chapter 5. Behavior of AASHTO Type
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 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
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3. Concrete compressive strength at
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findings were comments that the AAS
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including strand diameter, embedmen
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l d = l t + l fb = f si 3 d b + 1.5
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l d = l t + l fb ⎛ = ⎜ ⎝ f d
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Table A.1 Summary of Development Le
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strand release, the strand attempts
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Appendix B. Creep and Shrinkage B.1
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Changes in moisture migration: the
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t′: age of concrete at loading (d
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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
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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