settlement_of_shallow_foundations_on_granular_soils (Lutenegger ang DeGroot)

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rooo900lJmit rnpo..o by--..~BOO700•iiiw 600 a:.. iiiwf~500s~..400~300......... :.' '·-&.P.T,-"""" .......N • .......,_ """"......-~·"24 000 ··so ··vwy... . ... . ..20 000 5020016000 40-"""'12 000 30100 8 000 20 ......5000 2 3 4 5 6 7 8WIDTH B OF SQUARE FOOnNG IN METRES4 000 102 ooo 5 v. """Figure 6.26 van der Vlugt and Rosenthal (1989) Allowable Soil Pressure Chart.173
7.0 LOAD-SETTLEMENT BEHAVIOR OF SPREAD FOOTINGS ONGRANULAR SOILS-UNIVERSAL APPROACHThe settlement prediction methods previously described in this report generally suffer frombeing site specific and are based on a decoupling of the limit equilibrium and deformation behaviorof shallow foundations. Because of this, it is useful to approach the problem from a differentphilosophical viewpoint and search for an alternative approach. It may be possible to link thesettlement of shallow foundations resting on granular soil deposits to the limit equilibrium condition,i.e., ultimate bearing capacity. Since most shallow foundations are designed to function at workingloads well below the limiting value, which would produce a bearing capacity failure, it is normallythe settlement criteria which governs the overall design. This means that while a normal industryfactor of safety on the order of 3 against bearing capacity is sought, this level of loading providessufficient safety from a bearing capacity but generally allows excessive settlements, especially forsettlement critical structures. This means that a higher operational factor of safety is usually ineffect.7.1 BackgroundThere is substantial evidence in the literature which suggests that there is a direct connectionbetween load capacity and deformation offoundations for both deep and shallow foundations. Forexample, Trautmann and Kulhawy (1988) have shown that this link exists in the performance ofshallow foundations subjected to axial uplift loading. Based on the results of a large number offullscaleload tests conducted on shallow (D/B ,; 3) grillage and cast-in-place foundations, theysuggested that the uplift displacement under load could be expressed in terms of the normalized loadi.e., any given load divided by the load at failure. In order to express the deformation in a nondimensionalfashion, they suggested that the deformation be normalized with respect to the depthof burial (D) as shown in Figure 7.1 the depth of burial, D, which in effect identifies the active zoneof soil where the deformation occurs.In granular soils, it was found that the failure of the foundation occurred at a displacementcorresponding to about O.OOSD. When plotted non-dimensionally, as shown in Figure 7.1, theresults displayed a general shape expressed as a hyperbolic function by:Q/Qult = (z/D)/(0.013 + 0.67(z/D))[7.1]where:Q = Current LoadQuit = Ultimate Loadz= displacementD=Depth.174
Page 1 and 2:
SETTLEMENT OF SHALLOW FOUNDATIONSON
Page 3 and 4:
ACKNOWLEDGEMENTSThis study was fund
Page 5 and 6:
5.2.6 Alpan (1964) ................
Page 7 and 8:
LIST OF TABLESTable 2.1 Previous In
Page 9 and 10:
Figure 5.9 Schultze and Sherif(l973
Page 11 and 12:
Figure B.8 Updated Douglas Chart (O
Page 13 and 14:
2.0 BACKGROUND - SETTLEMENT OF SHAL
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HORIZONTAL DISPLACEMENT, mm10. 0Not
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3.1 Introduction3.0 DESIGN APPROACH
Page 19 and 20:
4.0 ELASTIC SOLUTIONS FOR ESTIMATIN
Page 21 and 22:
"o2.8-2.4t2.01.61.2(a)iII-~10520.80
Page 23 and 24:
- 0 2:::::>0a::- (!)-Q.1.5 H.......
Page 25 and 26:
2.52.0fl-1 1.5Figure 4.5 Janbu et a
Page 27 and 28:
thus underestimate settlement. A co
Page 29 and 30:
1.00.9 ~--~~~ ~t::$:::"--+-----+---
Page 31 and 32:
1.0~'-o0.90.80.70.60.5~~~-BURLAND\~
Page 33 and 34:
settlement of each layer. The layer
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ifa.=JO" S=Q867xplbxC 80 02 .Cs04 0
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0. I 00. 150.20m'-.NJ:>-~w0w>....<-
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I2IIfvEDG~- ~,..=.33~vc/-""CENTERJL
Page 41 and 42:
" ~...,I...,"~~....."'w 0-~'z z1.0~
Page 43 and 44:
2 - Compute the settlement of one c
Page 45 and 46:
s = settlementq = foundation stress
Page 47 and 48:
4.8 Wahls and Gupta (1994)A method
Page 49 and 50:
Corrections to the SPT blowcount sh
Page 51 and 52:
4.9.1 Standard Penetration TestNume
Page 53 and 54:
there are several techniques that h
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Overconsolidation ratio, OCRFigure
Page 57 and 58:
Table 4.3 Soil Modulus from Standar
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Table 4.5 Soil Modulus from Cone Pe
Page 61 and 62:
Table 4.5 Cont'dReference Relations
Page 63 and 64:
Table 4.6 Other Expressions for Soi
Page 65 and 66:
Table 5.1 Methods to Evaluate Settl
Page 67 and 68:
19. Stroud (1989)20. Berardi eta!.
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-100.-----~-----------------,~-----
Page 71 and 72:
the compression of the layer is cal
Page 73 and 74:
20 40 60 dO 100Std. Penetration Res
Page 75 and 76:
40 60 80 100RELATIVE DENSITY, PER C
Page 77 and 78:
VIa..LLI0::JVIS P T- NUMBERS OF BLO
Page 79 and 80:
Alp an suggested that the correctio
Page 81 and 82:
y = soil total unit weightCw = wate
Page 83 and 84:
1000~-------r----~~--------~-------
Page 85 and 86:
00 0·5 1·0 1·5·Ye2•0Figure 5,
Page 87 and 88:
s M~87 !1•D.U/B)p~<=::!::':'"'e11
Page 89 and 90:
N = uncorrected blowcountC, = embed
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I 2 3UNCONFINED COMPRESSIVE STRENGT
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~-~LU-LU~ eJ:.:t::\:!W~~k-----4----
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5.2.19 Stroud (1989)Stroud (1989) s
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'E-z~161412 J-100WIZI.D8 J-4 J- 1jz
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N)'Nq140 IIIN'YINcIIII20 80 I/N'Y 1
Page 101 and 102:
The soil stiffness is evaluated usi
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1 •••. ... .,1-: •. .......
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5.2.21 Anagnostopoulos eta!. (1991)
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Ll.p' = (2P cos 6 8)/rcz 2 [5.91]Ad
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0~·Illso ·~100 II~\~ 0••100 "
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5.3.5 Schmertmann (1970)In what may
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4.- Use Equation 5.95 to calculate
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Soil Type.QJNsandy silt 2.5sand & g
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IOr---.----,,---,---,,,---,---,----
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Table 5.5 Influence Factors for Ber
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Table 5.6 Reported Use ofPressureme
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q' =net footing pressureB = footing
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In order to recognize the strain ar
Page 127 and 128:
For different soils Menard suggeste
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5.5 Dilatometer TestMarchetti (1980
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Method B - Special MethodThis metho
Page 133 and 134: OCR= [K(OC)/(1-sin ~ )](1 10·' sin
Page 135 and 136: Figure 5.29 Settlement Ratio as a f
Page 137 and 138: 5.6.2 Barata (1973)B arata also poi
Page 139 and 140: 6"';_;51 v = o , 1~ c~ 4 o/:;0-~ "'
Page 141 and 142: and circular foundation; 4B for str
Page 143 and 144: ~N~~~~~~"' ~0.~100 1.0ii..., c. 10
Page 145 and 146: Table 5.9 Comparison of Settlement
Page 147 and 148: 6.0 ALLOWABLE BEARING CAPACITY CHAR
Page 149 and 150: 5lr)lr.tl\)J~2~'§ I~t--·/_'f()()/
Page 151 and 152: 7\~' "'--O&nseVery Dense..___ N=5o-
Page 153 and 154: also noted that "If the pressure co
Page 155 and 156: 6;:.:5~4~~ 3'~~ 2~~tl. I~~',I) 0(c!
Page 157 and 158: capacity is reduced, the allowable
Page 159 and 160: 6.6 Sowers (1962)Sowers (1962) in L
Page 161 and 162: 301-E~. (2-1 1 9)251-201-l\1050~1-"
Page 163 and 164: 800700~- N'qo- 0.05 qo OOB 8~0_!:!.
Page 165 and 166: It was stated by Mohan et al. (1971
Page 167 and 168: 1 4f--u.-(")1 2C IIVl'->- 1 0z!;;au
Page 169 and 170: 600(a) D/B = 1 (b) D/B = 0.5 (c) D/
Page 171 and 172: 6050z~- 40c:~0u~ 30/v----/0~ 20 ".0
Page 173 and 174: 250----200 ,........15010050•/...
Page 175 and 176: q. = NJO.Ol2B (kN/m 2 ) [6.27)Equat
Page 177 and 178: fl(m)6 600~N.:::~~"2 ~~M"5 500-~~4
Page 179 and 180: 0 2 4B,FT10 12Qo =ALLOWABLE BEARING
Page 181 and 182: 0 0 010c"' E~-V> "' 8.£~0-V>drr!'?
Page 183: Table 6.2 (continuted)Method lxlm 1
Page 187 and 188: The value of Q/Q, 1 , is essentiall
Page 189 and 190: Figure 7.3 Nondimensional Load-Sett
Page 191 and 192: 120~-------------------------------
Page 193 and 194: z00 0.7:5w 0.6f- <t~ 0.5~:::J 0.4--
Page 195 and 196: qb(s/0=5%)0.5 1.0 150~6-....2"~zUJ
Page 197 and 198: tDr= 59%q'YB0 20 40 6040 t,-Dr= 47%
Page 199 and 200: The bearing capacity factors are a
Page 201 and 202: 7.3 Review of Load TestsInitially,
Page 203 and 204: Table 7.2 Normalized Load-Settlemen
Page 205 and 206: Table 7.3 Normalized Load - Settlem
Page 207 and 208: Table 7.4 Normalized Load- Settleme
Page 209 and 210: 0.9* •+.•t * ' '........... ,
Page 211 and 212: 1.0'I' i 'I' i0.9~"' i "'v :'I' "'
Page 213 and 214: 8.0 SETTLEMENTS FROM CYCLIC LOADING
Page 215 and 216: 9.0 RECOMMENDATIONSBased on the res
Page 217 and 218: 4- Martin (1987) Method (PMT)5- Par
Page 219 and 220: Berardi, R., Jamiolkowski, M., and
Page 221 and 222: Engineering." Proceedings of the 2n
Page 223 and 224: Garga, V.K., and Quin, J.T., 1974.
Page 225 and 226: Kovacs, W.D., Evans, J.C. and Griff
Page 227 and 228: Meigh, A.C., 1963. "Discussion on S
Page 229 and 230: Parry, R.H.G., 1978. "Estimating Fo
Page 231 and 232: Schultze, E. and Sherif, G., 1973.
Page 233: Tucker, K.D., 1987. "Uplift Behavio
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