Alternative Support Systems for Cantilever - National Transportation ...

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• Determine the breakout strength of the system of torsional plates • Determine the torsional strength of the system of plates • Check to ensure that the Tn breakout is greater than Tu • Based on the breakout length above, choose depth of embedment for pipe - the breakout should not reach the surface of the concrete • Size welds to handle design loads (AASHTO LRFD Bridge Design Specifications Section 6.13.3.2.4) Embedded Pipe and Flexure Plate Design For the design of the flexural plate, the designer will need the following information from the FDOT program or their own design: • Design loads for shear, flexure, and torsion (Vu, Tu, and Mu) • Diameter and length of the circular pedestal portion of the foundation • Specified compressive strength of concrete • Embedded pipe dimensions The designer should then use this information and their own design knowledge to design the following for the embedded pipe and plate section (See Figure D-3): • Assume the number of idealized flexural bearing positions on flexure plate is 2 • Determine thickness of flexure plate, minimum of 1 inch • Determine diameter of flexure plate, minimum of 2 inches greater than embedded pipe outside diameter (maintain aspect ratio of width to thickness less than 2:1 to avoid prying action) • Determine the breakout edge distance, ca1 • Determine the angle available for each plate to breakout 176
• Determine the angle required for group effect • Check group effect. If group effect present, reduce the number of plates or diameter of shaft until no group effect occurs. • Determine length of breakout • Determine breakout area of one plate • Determine breakout area of equivalent anchor bolt • Determine basic shear strength of one torsional plate • Determine the breakout strength of one torsional plate • Determine the breakout strength of the system of torsional plates • Determine the torsional strength of the system of plates • Check to ensure that the Mn breakout is greater than Mu • Based on the breakout length above, verify depth of embedment for pipe - the breakout should not reach the surface of the concrete • Size welds to handle design loads (AASHTO LRFD Bridge Design Specifications Section 6.13.3.2.4) 177
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Report No. BDK75 977-04 Date: Augus
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Metric Conversion Table SYMBOL WHEN
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ALTERNATIVE SUPPORT SYSTEMS FOR CAN
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EXECUTIVE SUMMARY During the 2004 h
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CHAPTER TABLE OF CONTENTS 1 INTRODU
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Torsion Test Data .................
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LIST OF FIGURES Figure page Figure
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Figure 4-15. Arrangement of the LVD
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CHAPTER 1 INTRODUCTION This project
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CHAPTER 2 BACKGROUND The following
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information obtained in the late 19
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these problems. The concern with fa
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opposite side, see Figure 2-2 The s
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2.2.4 Helical Pipes This option wou
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2.3 Alternative Foundations from Ot
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Figure 2-10. Drilled concrete piles
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Figure 2-13. Grouted soil anchors G
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The pad and pier foundation, found
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comments and recommendations on pre
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CHAPTER 3 DESIGN IMPLICATIONS Based
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Figure 3-2. Differences between con
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2 [ ] 2 2 ( r ) + 3. 25 ( r ) − (
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eakout surface for a single plate,
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strength of a headed anchor in tens
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Figure 3-9. Schematic of anticipate
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Vbfp l e tfp bfp f’c ca1 = the ba
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3.2.2 Equivalent Side-Face Blowout
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computed. See Equation 3-14 below t
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One method to quantify the failure
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• An additional 12-4.5” long, 1
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Applied load Lever arm Figure 4-4.
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Figure 4-8. Isometric view of embed
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Flexural plate breakout area Torsio
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4.2.4 Annular Base Plate Design The
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torsional strength of the lever arm
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4.4 Concrete Block and Tie-Down Des
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Figure 4-13. Arrangement of the LVD
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4.7 Summary of Torsion and Flexure
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foundation displayed the predicted
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Figure 5-5. Specimen at failure 5.1
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Figure 5-7. Torsional moment and ro
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torsional 45 degree crack formation
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Figure 5-11. Widening of concrete b
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Failure cracks widen Bond loosens F
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Rear of shaft Figure 5-14. Load and
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testing, signifying that the predic
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provided in NCHRP Report 412 were i
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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
Page 141 and 142: Check_Bolt_Shear := "Sufficient Str
Page 143 and 144: Check Reinforcement No_Bars_Block_R
Page 145 and 146: Tie-Down Design Block Properties Wi
Page 147 and 148: Vmax Total Load that the Tie-down m
Page 149 and 150: λpf := .38⋅ λpw := 3.76⋅ E F
Page 151 and 152: Input and Properties Shaft Torsion
Page 153 and 154: ψcV := 1.4 ψecV := 1.0 ψedV := 1
Page 155 and 156: lbreakout := L + 2⋅1.5ca1 lbreako
Page 157 and 158: Rn_weld := Throat⋅FW Rn_weld 11.1
Page 159 and 160: ⎛ ⎜ ⎜⎜⎜⎜⎜⎜⎜ 9.250
Page 161 and 162: Flexural Capacity of T-Plates Using
Page 163 and 164: FAILURE EQUATIONS Torsion Threshold
Page 165 and 166: Required Length of Shaft Based on B
Page 167 and 168: Design Axial Strength ϕcomp := .90
Page 169 and 170: Design Axial Strength ϕcomp := .90
Page 171 and 172: Zp := ⎛ ⎜ ⎝ bp tp⋅ 2 ⎞
Page 173 and 174: Bolt Properties - D1" ASTM A325 Cen
Page 175 and 176: CONCRETE BLOCK Concrete Block Desig
Page 177 and 178: Check Shear Check_Shear_B := "Suffi
Page 179 and 180: 7'-4" 8" 5'-4" 8" 1'-3" Calculate s
Page 181 and 182: Required Capacity of the Channel As
Page 183 and 184: Check_Flange_Compact_Unit := "Compa
Page 185 and 186: Rear of Shaft Face of Shaft Figure
Page 187 and 188: Bolt slippage ends Predicted failur
Page 189 and 190: APPENDIX D DESIGN GUIDELINES For th
Page 191: The designer should then use this i
Page 195 and 196: Superstructure Base Connection Foun
Page 197 and 198: 1.5ca1 1.5ca1 Length of bearing are
Page 199 and 200: Vu = 9.04 kip T .u = 198.88 ft·kip
Page 201 and 202: Increase threaded rod diameter to 2
Page 203 and 204: Embedded Pipe and Torsion Plates De
Page 205 and 206: ⎝ ⎠ Check_Breakout_Torsion := "
Page 207 and 208: Lbreakout := tflex.plate + 2⋅1.5c
Page 209 and 210: ( ) .85 if fc < 4000psi β 1 f c .6
Page 211 and 212: REFERENCES 1. Cook, R.A., and Halco
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