Alternative Support Systems for Cantilever - National Transportation ...

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The maximum length for le is limited to 8da as delineated in ACI 318-08 D6.2.2. The constant 7 from Equation 3-1 was determined from a 5% fractile with cracked concrete. The constant 7 becomes a constant 13 for the mean breakout strength of a single anchor in uncracked concrete loaded in shear perpendicular to the edge. The mean breakout strength is described in Equation 3-2, as shown below (12). ( ) 5 . 1 0. 2 ⎛ e V ⎜ ⎛ l ⎞ b = 13 ⎜ ⎜ d ⎟ a ⎝ ⎝ ⎠ ⎞ d ⎟ a λ ⎟ ⎠ f ′ c ca1 (3-2) ACI 318-08 (5) describes the nominal breakout strength of an anchor loaded in shear perpendicular to the edge in Equation D-21 and is described below as Equation 3-3. Figure 3-4 depicts the projected concrete failure area of a single anchor in rectangular concrete. Figure 3-5 depicts the projected concrete failure area of a single anchor in cylindrical concrete. An important distinction to note between the failure area of a single anchor in rectangular concrete and cylindrical concrete is the edge distance ca1. Equation 3-4 details how to calculate the value of ca1 for an anchor adjacent to a circular edge. A = ψ ψ ψ V (3-3) Vc V c b ed , V c, V h, V AVco Where Vcb AVc AVco ψed,V ψc,,V ψh,V b = The nominal concrete breakout strength in shear of a single anchor (lb.) = The projected area of the failure surface for a single or group of anchors, used to determine the shear strength (in 2 ) = The projected concrete failure area of a single anchor, for calculation of strength in shear, if not limited by corner influences, spacing, or member thickness (in. 2 ) = 4.5(ca1) 2 , based on an ≈35° failure cone (Figure 2-16) = The factor used to modify shear strength of anchors for edge effects, ACI 318-08 Section D.6.2.6 = The factor used to modify shear strength of anchors based on presence or absence of cracks in concrete and presence or absence of supplementary reinforcement, ACI 318-08 Section D.6.2.7, accounted for in Equation 2-2 = The factor used to modify shear strength of anchors based on anchor location and effective length of anchor, ACI 318-08 Section D.6.2.8 26
2 [ ] 2 2 ( r ) + 3. 25 ( r ) − ( r ) ca1 = b s 3. 25 b − rb (3-4) Where ca1 = distance from the center of an anchor shaft to the edge of concrete taken in the direction of the applied shear (in.) rb = The distance from the center of the cylindrical shaft to the center of the anchor bolt (in.) = The radius of the cylindrical shaft (in.) rs ≈35° Vb 1.5ca1 1.5ca1 AVco 1.5ca1 1.5ca1 ca1 27 1.5ca1 Vb ≈35° AVco=1.5ca1·2(1.5ca1) =4.5(ca1) 2 Figure 3-4. Shear breakout of a single anchor in rectangular concrete 1.5ca1 As FDOT Report BD545 RPWO #54 determined, the failure loading on the foundation’s anchor group was torsion (1). This torsion can be resolved into shear forces acting parallel to an edge. ACI 318-08 prescribes in section D6.2.1 that the nominal concrete breakout strength of a single anchor loaded in shear parallel to an edge shall be permitted to be twice the value of the shear force determined as Vcb, which assumes shear loading perpendicular to an edge. Now that the basic equations for concrete breakout due to shear on anchor bolts have been established, it is appropriate to address the changes in these equations to satisfy the differences between the anchor breakout and the expected experimental breakout. The mean breakout
Page 1 and 2: Report No. BDK75 977-04 Date: Augus
Page 3 and 4: Metric Conversion Table SYMBOL WHEN
Page 5 and 6: ALTERNATIVE SUPPORT SYSTEMS FOR CAN
Page 7 and 8: EXECUTIVE SUMMARY During the 2004 h
Page 9 and 10: CHAPTER TABLE OF CONTENTS 1 INTRODU
Page 11 and 12: Torsion Test Data .................
Page 13 and 14: LIST OF FIGURES Figure page Figure
Page 15 and 16: Figure 4-15. Arrangement of the LVD
Page 17 and 18: CHAPTER 1 INTRODUCTION This project
Page 19 and 20: CHAPTER 2 BACKGROUND The following
Page 21 and 22: information obtained in the late 19
Page 23 and 24: these problems. The concern with fa
Page 25 and 26: opposite side, see Figure 2-2 The s
Page 27 and 28: 2.2.4 Helical Pipes This option wou
Page 29 and 30: 2.3 Alternative Foundations from Ot
Page 31 and 32: Figure 2-10. Drilled concrete piles
Page 33 and 34: Figure 2-13. Grouted soil anchors G
Page 35 and 36: The pad and pier foundation, found
Page 37 and 38: comments and recommendations on pre
Page 39 and 40: CHAPTER 3 DESIGN IMPLICATIONS Based
Page 41: Figure 3-2. Differences between con
Page 45 and 46: eakout surface for a single plate,
Page 47 and 48: strength of a headed anchor in tens
Page 49 and 50: Figure 3-9. Schematic of anticipate
Page 51 and 52: Vbfp l e tfp bfp f’c ca1 = the ba
Page 53 and 54: 3.2.2 Equivalent Side-Face Blowout
Page 55 and 56: computed. See Equation 3-14 below t
Page 57 and 58: One method to quantify the failure
Page 59 and 60: • An additional 12-4.5” long, 1
Page 61 and 62: Applied load Lever arm Figure 4-4.
Page 63 and 64: Figure 4-8. Isometric view of embed
Page 65 and 66: Flexural plate breakout area Torsio
Page 67 and 68: 4.2.4 Annular Base Plate Design The
Page 69 and 70: torsional strength of the lever arm
Page 71 and 72: 4.4 Concrete Block and Tie-Down Des
Page 73 and 74: Figure 4-13. Arrangement of the LVD
Page 75 and 76: 4.7 Summary of Torsion and Flexure
Page 77 and 78: foundation displayed the predicted
Page 79 and 80: Figure 5-5. Specimen at failure 5.1
Page 81 and 82: Figure 5-7. Torsional moment and ro
Page 83 and 84: torsional 45 degree crack formation
Page 85 and 86: Figure 5-11. Widening of concrete b
Page 87 and 88: Failure cracks widen Bond loosens F
Page 89 and 90: Rear of shaft Figure 5-14. Load and
Page 91 and 92: testing, signifying that the predic
Page 93 and 94:
provided in NCHRP Report 412 were i
Page 95 and 96:
6.2.2 Tapered Embedded Steel Pipe a
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Figure 6-3. FDOT Design Standards I
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This option provides a possible alt
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6.2.5 Cast-in-Place Solid Concrete
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This option does have some disadvan
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Figure 6-9. Embedded steel pipe and
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However, the fillet welds are susce
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APPENDIX A TEST APPARATUS DRAWINGS
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Figure A-3. Dimensioned side elevat
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Figure A-5. Dimensioned drawings of
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Figure A-7. Dimensioned plan drawin
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Figure A-9. Dimensioned drawing of
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Figure A-11. Dimensioned view of em
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STIFFENER DESIGN Calculation of Cap
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L breakout Concrete Breakout Equiva
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Abrg L⋅b 7 in 2 := = .5 Nsb 200
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β 1 f c Calculations Using ACI Str
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Determine Flexural Capacity of Roun
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DEVELOPMENT LENGTHS OF FLEXURAL REI
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Short Pipe Design Flexural Strength
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Long Pipe Design Flexural Strength
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Superstructure Assembly Strength -
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Weld Design Tn_blowout Vweld := Tor
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Check_Bolt_Shear := "Sufficient Str
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Check Reinforcement No_Bars_Block_R
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Tie-Down Design Block Properties Wi
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Vmax Total Load that the Tie-down m
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λpf := .38⋅ λpw := 3.76⋅ E F
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Input and Properties Shaft Torsion
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ψcV := 1.4 ψecV := 1.0 ψedV := 1
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lbreakout := L + 2⋅1.5ca1 lbreako
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Rn_weld := Throat⋅FW Rn_weld 11.1
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⎛ ⎜ ⎜⎜⎜⎜⎜⎜⎜ 9.250
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Flexural Capacity of T-Plates Using
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FAILURE EQUATIONS Torsion Threshold
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Required Length of Shaft Based on B
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Design Axial Strength ϕcomp := .90
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Design Axial Strength ϕcomp := .90
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Zp := ⎛ ⎜ ⎝ bp tp⋅ 2 ⎞
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Bolt Properties - D1" ASTM A325 Cen
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CONCRETE BLOCK Concrete Block Desig
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Check Shear Check_Shear_B := "Suffi
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7'-4" 8" 5'-4" 8" 1'-3" Calculate s
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Required Capacity of the Channel As
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Check_Flange_Compact_Unit := "Compa
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Rear of Shaft Face of Shaft Figure
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Bolt slippage ends Predicted failur
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APPENDIX D DESIGN GUIDELINES For th
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The designer should then use this i
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• Determine the angle required fo
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Superstructure Base Connection Foun
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1.5ca1 1.5ca1 Length of bearing are
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Vu = 9.04 kip T .u = 198.88 ft·kip
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Increase threaded rod diameter to 2
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Embedded Pipe and Torsion Plates De
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⎝ ⎠ Check_Breakout_Torsion := "
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Lbreakout := tflex.plate + 2⋅1.5c
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( ) .85 if fc < 4000psi β 1 f c .6
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REFERENCES 1. Cook, R.A., and Halco
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