Bursting and Spalling in Pretensioned U-Beams - Ferguson ...

More documents

Recommendations

Info

B.3.4 Transmission Length (Clause 6.9.11.4)Equation B.9where:= factor considering release method:= 1.0 for gradual release, and= 1.25 for sudden release.= factor considering action to be verified:= 1.0 for moment and shear capacity, and= 0.5 for transverse stresses in anchorage zone.= factor considering bond:= 0.5 for strands, and= 0.7 for indented or crimped wires= basic anchorage length= stress in strands just after release (i.e. after elastic losses)= strand design stress210
B.3.5 Bursting Force (Clause 6.9.12.2)Figure B.1 Symmetrical prism model for CEB-FIP bursting provisions(CEB-FIP MC 1990)Equation B.10where:= symmetrical prism length (as tendons are anchored by bond)= prism height (twice the distance from prestress centroid to bottom fiber)= transmission length211
Page 1 and 2:
CopyrightbyDavid Andrew Dunkman2009
Page 3 and 4:
Bursting and Spalling in Pretension
Page 5 and 6:
Bursting and Spalling in Pretension
Page 7 and 8:
2.4.2.3 Itani & Galbraith, 1986 ...
Page 9 and 10:
4.2.2.4 Beam 1: Lateral-Bar Burstin
Page 11 and 12:
List of TablesTable 2.1 Range of st
Page 13 and 14:
Figure 2.25 Mechanical gage points
Page 15 and 16:
Figure 3.30 Thermocouple placement
Page 17:
CHAPTER 1Introduction1.1 IMPETUS FO
Page 20:
At present, current end-region deta
Page 23 and 24:
Figure 2.1 Severe cracking in a pre
Page 25 and 26:
through use of tensioned, high-stre
Page 27 and 28:
As splitting stress is bond-related
Page 29 and 30:
Figure 2.6 Effect of bursting & spa
Page 31 and 32:
magnitude of the end-region transve
Page 33 and 34:
FEA can readily output color maps o
Page 35 and 36:
2.3.1.3 Plastic Analysis of Beam En
Page 38 and 39:
force can increase by 400% (Yettram
Page 40 and 41:
2.4 EXPERIMENTAL STUDIES OF BURSTIN
Page 42 and 43:
The trial specimens included one 40
Page 44 and 45:
mechanical gage (2 in. gage length)
Page 46 and 47:
Bursting stress(normalized by prest
Page 48 and 49:
proprietary post-tensioning anchors
Page 50 and 51:
Though Marshall and Mattock placed
Page 52 and 53:
ectangular beam” (p. 21). At high
Page 54 and 55:
Most beams observed to crack did so
Page 56 and 57:
The behavior of these beams was dom
Page 58 and 59:
2.4.2 Studies of End-Region Transve
Page 60 and 61:
Figure 2.28 I-beams studied by Mars
Page 62 and 63:
transverse forces compared to those
Page 64 and 65:
(a) Actual spalling stress variatio
Page 66 and 67:
stirrups in Gergely, Sozen and Sies
Page 68 and 69:
50% more reinforcement than require
Page 70 and 71:
strength concrete, increasingly hig
Page 72 and 73:
the reinforcement located within th
Page 74 and 75:
Typical crack patterns for the beam
Page 76 and 77:
“Very common”crack locationPred
Page 78 and 79:
Figure 2.38 Typical gage locations
Page 80 and 81:
2.4.2.7 Smith et al., 2008Most rece
Page 82 and 83:
the provided transverse reinforceme
Page 84 and 85:
Itani and Galbraith (1986) reported
Page 86 and 87:
Figure 2.45 Confining reinforcement
Page 88 and 89:
cracks located along lines of prest
Page 90 and 91:
odies relevant to pretensioned conc
Page 92 and 93:
than that in another shape. For thi
Page 94 and 95:
Figure 2.47 Required splitting rein
Page 96 and 97:
No attempt was made in the Tentativ
Page 98 and 99:
No citation is provided in the PCI
Page 100 and 101:
Section Propertiesy b22.4 in.A 1120
Page 102 and 103:
minimum for greater skews. For beam
Page 104 and 105:
treatment (counting the transverse
Page 106 and 107:
Pretensioned/post-tensioned beams h
Page 108 and 109:
Figure 2.57 Harped strands in webs
Page 110 and 111:
transversereinforcementwithin voidp
Page 112 and 113:
2.8 SUMMARYIn this chapter, literat
Page 114 and 115:
3.2.1.1 Linear and Nonlinear Stress
Page 116 and 117:
Empirical expressions can be used t
Page 118 and 119:
where: 0.021 = spalling force,
Page 120 and 121:
3.3 CONCRETE PROPERTIES3.3.1 Concre
Page 122 and 123:
It was reasoned that the dimensiona
Page 124 and 125:
Splitting tensile-strength testing
Page 126 and 127:
For temperature-match curing, therm
Page 128 and 129:
3.4.1 Reinforcing-Bar Mechanical Te
Page 130 and 131:
Grade 60 rebar yielded at 65 ksi an
Page 132 and 133:
Equation 3.10where:ε1,2 = gage str
Page 134 and 135:
Figure 3.17 Typical strand failure
Page 136 and 137:
SouthNorth North120NorthSouthFigure
Page 138 and 139:
Beam 1 also included an additional
Page 140 and 141:
Figure 3.22 Strand strain-gage inst
Page 142 and 143:
Figure 3.25 Interface board used to
Page 144 and 145:
eam has a “hot spot” (measureme
Page 146 and 147:
3.6 BEAM FABRICATION3.6.1 Beam Cast
Page 148 and 149:
Figure 3.33 Installing the interior
Page 150 and 151:
In order to use a pretensioning bed
Page 152 and 153:
standardside-formprofilespecialtape
Page 154 and 155:
Figure 3.41 Strands installed, tens
Page 156 and 157:
Correspondence between the values o
Page 158 and 159:
Figures 3.45 to 3.50 show the fabri
Page 160 and 161:
Figure 3.49 Casting end block (and
Page 162 and 163:
Figure 3.52 Detensioning by gradual
Page 164 and 165:
CHAPTER 4Results & Discussion4.1 OV
Page 166 and 167:
The strain time history for each ga
Page 168 and 169:
1DNorthSouth1E18 ksi1C1C,E1D1521B1B
Page 170 and 171:
Figure 4.4 Beam 1 prestress losses
Page 172 and 173:
crack adjacent to this location was
Page 174 and 175:
The temperatures in the end blocks
Page 176 and 177: Table 4.4 Beam 2 applied prestressi
Page 178 and 179: Figure 4.10 Beam 2 prestress losses
Page 180 and 181: terms of force distribution seems t
Page 182 and 183: limits were only exceeded at locati
Page 184 and 185: spalling stresses were measured in
Page 186 and 187: transverse reinforcement contained
Page 188 and 189: Based on Figure 4.18, the 4% Pi des
Page 190 and 191: Uniform and linearly-decreasing tra
Page 192 and 193: 4.3.5 Contributing Factors to High
Page 194 and 195: stress ratio multiplied by a typica
Page 196 and 197: Figure 4.25 Relation between total
Page 198 and 199: 4.4.1 Recommended Texas U-Beam Rein
Page 200 and 201: Figure 4.28 Proposed end-region det
Page 202 and 203: At present, AASHTO LRFD (2009) lack
Page 204 and 205: CHAPTER 5Conclusions5.1 SUMMARY OF
Page 206 and 207: tested at transfer and under shear
Page 208 and 209: APPENDIX ADatabase of Transverse-Ba
Page 210 and 211: 194Figure A.1 U-beam with skewed en
Page 212 and 213: 196Figure A.3 Shallow Texas bulb te
Page 214 and 215: 198Figure A.5 Lightweight-concrete
Page 216 and 217: 200Figure A.7 Washington bulb tee (
Page 218 and 219: 202Figure A.9 Nebraska bulb tees an
Page 220 and 221: 204Figure A.11 Nebraska bulb tees a
Page 222 and 223: 206Figure A.13 Shallow I-beams
Page 224 and 225: where:= lower-bound concrete tensil
Page 228 and 229: Equation B.11where:= bursting force
Page 230 and 231: 50High Web gage4030Max Moment heigh
Page 232 and 233: C.2 CONCRETE RELEASE STRENGTHA bott
Page 234 and 235: Table C.1 Specimen Design for Beams
Page 236 and 237: Table D.1 Beam 1 match-cured cylind
Page 238 and 239: D.1.2 Beam 28Release-Point Cylinder
Page 240 and 241: Cylinder Strength (ksi)131197Ambien
Page 242 and 243: D.2 REINFORCING-BAR MODULUS & STREN
Page 244 and 245: APPENDIX EEnd-Block Temperature Pro
Page 246 and 247: E.2 BEAM 2T max = 142°F∆T = 30°
Page 248 and 249: REFERENCESREFERENCED STANDARDSAmeri
Page 250 and 251: Fédération Internationale du Bét
Page 252 and 253: Davis, R.T.; Buckner, C.D. & Ozyild
Page 254 and 255: Lin, T.Y. & Burns, N.H. (1981), Des
Page 256 and 257: Stone, W.C. & Breen, J.E. (1984),
Page 258: VITADavid Andrew Dunkman was born 2
show all

Bursting and Spalling in Pretensioned U-Beams - Ferguson ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?