Research Article Development of Curves of Laterally Loaded Piles in Cohesionless …downloads.hindawi.com/journals/tswj/2014/917174.pdf · 2019-07-31 · Research Article Development

Research ArticleDevelopment of 119901-119910 Curves of Laterally Loaded Piles inCohesionless Soil

Mahdy Khari Khairul Anuar Kassim and Azlan Adnan

Department of Geotechnics and Transportation Faculty of Civil Engineering Universiti Teknologi Malaysia81300 Skudai Johor Bahru Malaysia

Correspondence should be addressed to Mahdy Khari mehdikharigmailcom

Received 24 October 2013 Accepted 2 December 2013 Published 16 January 2014

Academic Editors C W Chang-Jian and M Vona

Copyright copy 2014 Mahdy Khari et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

The research on damages of structures that are supported by deep foundations has been quite intensive in the past decade Kinematicinteraction in soil-pile interaction is evaluated based on the p-y curve approach Existing p-y curves have considered the effects ofrelative density on soil-pile interaction in sandy soil The roughness influence of the surface wall pile on p-y curves has not beenemphasized sufficientlyThe presented study was performed to develop a series of p-y curves for single piles through comprehensiveexperimental investigations Modification factors were studied namely the effects of relative density and roughness of the wallsurface of pile The model tests were subjected to lateral load in Johor Bahru sand The new p-y curves were evaluated based onthe experimental data and were compared to the existing p-y curves The soil-pile reaction for various relative density (from 30to 75) was increased in the range of 40ndash95 for a smooth pile at a small displacement and 90 at a large displacement Forrough pile the ratio of dense to loose relative density soil-pile reaction was from 20 to 30 at a small to large displacement Directcomparison of the developed p-y curve shows significant differences in the magnitude and shapes with the existing load-transfercurves Good comparison with the experimental and design studies demonstrates the multidisciplinary applications of the presentmethod

1 Introduction

Significant damages of structures supported by deep founda-tions due to complete or partial collapse during earthquakeshas been observed in the past (El Naggar and Novak 1995[1ndash3]) These authors have demonstrated the paramountimportance of the soil-pile-superstructure interaction (SPSI)in the seismic behavior of structures [4] Kinematic inter-action in SPSI is due to presence of pile foundation in theground Several methods are widely used to determine thekinematic interaction such as finite element method (FEM)[5 6] boundary element method (BEM) [1 7] and beam onnonlinear winkler foundation (BNWF) [2 4 8 9] The FEMand BEM approaches are versatile techniques Although theSPSI analysis can be performed coupled without site responseanalysis it is very expensive from the calculation viewpoint[4] To evaluate the behavior of laterally loaded pile in thekinematic interaction the BNWF method is widely usedin research practices [4 9ndash11] McClelland and Focht [12]organized the BNWF method In the BNWF method the

soil and pile are modeled as nonlinear springs and linearelements respectivelyThe stiffness coefficient of the spring isevaluated based on the load-transfer approach often knownas p-y curve method

Many investigators have developed p-y curves for clayeysoils [10 13 14] and for sandy soils [10 15 16] Howeverthese developed curves do not account some parameters suchas relative density of sandy soil side friction and bendingstiffness of the pile This research has aimed to develop aseries of p-y curves through comprehensive experimentalinvestigations in Johor Bahru sand for a single pile subjectedto lateral load

2 Brief Review

The behavior of soil-pile interaction has been analyzedusing the concept of subgrade modulus In fact the staticequilibrium between pile and surrounding soil must beinitially obtained Kondner [17] performed a series triaxial

Hindawi Publishing Corporatione Scientific World JournalVolume 2014 Article ID 917174 8 pageshttpdxdoiorg1011552014917174

2 The Scientific World Journal

compression tests to obtain the stress-strain relationshipof soil where the p-y curves by hyperbolic function wereestablished In 1970 Matlock assumed that soil reaction at apoint dependent only on the pile deflection at that point andthe reaction is independence of pile deflection in the depthsof above and below of the point of interest Reese et al [15]developed a p-y curve from the of the full scale load testsThe curve consisted of an initial straight line (119901 = 119896119901119910119911119910 z =desired depth k119901119910 = subgrade modulus) a parabolic section(119901 = 1198621199101119899 119862 = 119901119898119910

1119899

119887 p119898 is soil pressure at y119887) between

119910119887 = 11986360 and 119910119906 = 311986380 (D = pile diameter) and a finalstraight line (119901 = 119860 119904119901119906 119860 119904 = empirical factor p119906 = ultimateresistance derivation from analysis of a wedge) establishedat 119910119906 It is noteworthy that the curve is same for sands inboth above and below the water table Weeselink et al [18]developed p-y curves for use in calcareous soils which is givenbelow as follows

119875 = 119877(119911

1199110)

119899

(119910

119863)

119898

(1)

where 1199110 = constant length taken as 1m R = control variablefor curve stiffness (850 kPa) and m and 119899 are empiricalfactors Other researchers developed the values of119877 119899 and119898[19] In 2001 Dyson and Randolph developed the curves foruse in calcareous soils They added the unit weight factor toWeeselinkrsquos equation Scott [20] performed centrifuge tests toinvestigate the soil-pile interaction and suggested the bilinearfunction to model the p-y curve as presented in the followingequation

119875 =1198631205901015840

0

(1120587) (1sin2119876 + 1(3 minus 4119863))05 (2)

where 12059010158400= (1205901015840

1+ 1205901015840

2+ 1205901015840

3)3

OrsquoNeill and Murchison (1984) studied the p-y curves insand andmodified the suggested equations by Reese et al [15]as shown in the following equation

119875 = 120578119860119875119906 tanh [119896119911119910

119860119875119906] (3)

where 120578 and 119896 are factors for shape of pile (ie for circularcross-section = 1) and initial modulus of subgrade reactionrespectively 119863 is pile diameter and 119911 is the depth 119860 is acoefficient based on loading conditions (static or cyclic) and119875119906 is determined based on wedge type and flow failure whichtakes from the smaller from the following equations

119875119906119889 = 1198623119863119911119910 119875119904119906 = (1198621119911 + 1198622119863) 119911120574 (4)

The three coefficients 1198621 1198622 and 1198623 (as function of the fric-tion angle) are used to calculate the ultimate soil resistanceThe initial modulus of soil reaction is computed using theexperimental factor 119896Thismethod is adopted by the API [21]as amodified shape of the p-y curves for sand for offshore pilefoundations

3 Experimental Work

The schematic diagram of the test setup is shown in Figure 1The dimensions of rectangular soil tank were 900mm inlength 700mm in width and 65mm in height To minimizethe box boundaries effects the size of soil tank was extendedup to 8ndash12D and 3-4D in the direction and perpendicular tolateral load respectively [22] In additional the soil thicknesswas kept below pile tip at least 6D

Lateral load was applied to piles at the surface of themodel ground through a pulley arrangement with flexiblewire attached to pile cap (Figure 1) The other end wasattached to the loading pan The loads were applied bygradually increasing the dead weight in the pan

31 Model Pile and Instrumentation As Figure 2 shows themodel pile wasmade of aluminumalloy tubingwith a value ofYoungrsquos modulus of 698GPa 1588mm in out diameter (119863)and 1388mm in inside diameter The embedded length-to-diameter ratio (119897119863) of pile was equal to 32The pile diameterwas around 16 times greater than the maximum particle sizefor sand which satisfied the recommended ratios in excess of15ndash30 to avoid scale effects [23] The properties of the modelpile were scaled by a dimensional analysis (Buckingham Pitheorem) with the properties of the basic prototype pile ofPenang Second Crossing in Malaysia A steel plate was usedas a pile cap for the single pile To satisfy the fixed headconditions the pile was passed through a hole in the capand then screwed to angle profiles (length = 50mm) weldedon the hole (Figure 2) The tests were conducted on smooth(wall friction of pile was low) and rough (fine sandwas pastedaround the pile by adhesive) single piles in dense (119863119903 = 75)and loose (119863119903 = 30) sand

A typical test (shown in Figure 1) included nine instru-ments two linear variable differential transducer (LVDT) tomeasure the deflection of the pile and seven levels of electricalstrain gauges having resistance of 350 plusmn 01Ω to measurebending moments The strain gauges were fixed along theouter surface of the pile The distances of the gauges were atcloser and larger spacing near ground surface and towardsthe pile tip respectively (Figure 2) They were coated with a05mm thick layer of epoxy for protection

Gauge constants were calculated for every one of thegauges separately The pile was supported on a set of edgesFifteen different pure moments were applied over the centralportion of pile (Figure 2) The values of observed strainand applied moments were correlated to compute the gaugeconstant at each gauge location (Figure 3) The constantwas determined by means of the method of least squaresDuring the calibration the central deflection of pile wasobserved The flexural stiffness (EI) was computed to be91 times 10

6Nsdotmm2

32 Soil Properties and Sample Preparation The tests con-ducted on the dried sand (ie in the laboratory temperature)The soil samples were from Johor Bahru in Malaysia Thesampled sand was classified as SP according to the UnifiedSoil Classification System (USCS) The medium diameter

The Scientific World Journal 3

Data recorder Strain gauges wires

LVDT

Straingauges

Johor Bahru sand

65 cm

90 cm

Pulley

Flexible wire

Loadingpan

Figure 1 Schematic view of experimental setup

Figure 2 Pile and pile cap setup in soil box

(D50) and uniformity coefficient (119862119906) of sand were 0532and 017mm respectively and particle sizes in a range of0075ndash097mm with the gradation are shown in Figure 4Based on British Standard methods (BS-1377) minimumand maximum unit weights of sand were 1374 kNm3 and1638 kNm3

To reconstruct the sand samples several methods havebeen developed by investigators such as vibration tampingand pluviation [24] The prepared samples using the pluvi-ation and tamping technique often result in a specimen ofhomogenous and nonuniform density respectively Accord-ingly the newly designed mobile pluviator was utilized inthis research to reconstruct the dry sandy soil samples usingthe dry pluviation method (Figure 5) The newly developedmobile pluviator by Khari et al [11] consisted mainly of a soilbin (hopper Figure 5 no 1) the diffuser system (the threesieves Figure 5 no 3) and sand collector a fixing device to setup these components so as the whole system was carried by amoveable steel frame As Figure 5 shows the interchangeablecircular wood plates (shutter plates Figure 5 no 2) wereinstalled in the bottom of the sand hopper The four patternsof the shutter plates were formed in a different manner of thedistribution of the holes for the sake of controlling the rateof the soil discharge While the apparatus was movable thedifferent factors were examined to obtain a wide range of the

7 cm 4 cm 4 cm 5 cm 5 cm 6 cm 9 cm 10 cm

G1 G2 G3 G4 G5 G6 G7

Load

(a)

700

600

500

400

300

200

100

0

0 100 200 300 400 500 600

Strain (10e minus 6)M

omen

t (Nmiddotcm

)(b)

Figure 3 Relationship between strain and moment (a) Pile in puremoment (b) fitted straight line

0

20

40

60

80

100

001 01 1 10

Perc

ent fi

ner

Particle size (mm)

Figure 4 Gradation curve of the Johor Bahru sand

relative densities The falling height and the rate of pouringhad the opposite effects on the relative density [25] Based onthe obtained results the two patterns selected consisted of 11holes (diameter = 18mm) and 16 holes (diameter = 10mm)distributed evenly in the shutter to achieve the dense andthe loose sand samples with relative density of 75 and 30respectively The falling height was kept constant at 700mmfrom the surface of the model ground so it was more thanthe critical height to obtain terminal velocity The pour wasstopped when the height of sand rained in the soil tank was30mm thicker than the required height and finally the extrasoils were removed

33 Test Procedure Thepileswere first located in the center ofthe soil tank and fixed with the cap Verticality of the pile wasmaintained using a guide frame After placing themodel pile


1

2

3

Figure 5 Mobile Pluviator System

the soil box was filled with the dried sand using the mobilepluviator apparatus

To monitor uniformity and relative density during thesamples preparation three small boxes (cylinder shaped witha volume of 455 cm3) were placed on the surface of sampleprior to sand spreading The surface of the model groundwas leveled when the required height was achieved At least24 hours elapsed before applying any load to the pile Toeliminate any time effects due to sand consolidation straingauge readings were taken after 10 minutes for each loadincrement The data measured from the LVDTs and straingauges were stored on a computer data acquisition system

4 Results and Discussion

A series of tests were performed on single fixed-head pilesin loose (119863119903 = 30) and dense (119863119903 = 75) sand The testsT44 and T45 were performed on smooth piles and T48 andT47 were conducted on rough piles in dense and loose sandrespectivelyThe loads were applied to piles in an incrementalmanner

The strain values obtained were converted to momentsby multiplying strain by the previously estimated gaugeconstants A smooth fourth-order polynomial was thenfitted through the experimentally moments observed Lateraldisplacements (y) and soil-pile reactions (p) were computedby double integration and differentiation of moment curvealong the depth of pile respectively

The variation of deflection (y) along pile is presented inFigure 6 As stated earlier the integration of the slope curveleads to deflection curves versus depth along the pile It canbe noted that at a depth of 26 to 28 cm pile did not show anydeflection because of active length of pile (Figure 6)

Figure 7 shows the effects of relative density on themaximum bending moment along the pile As can be seen inFigure 8(b) the maximum bending moments were observedin the rough pile in loose and dense densities This isprimarily due to the fact that as friction between soil and

0

5

10

15

20

25

30

35

40

Dep

th (c

m)

Deflection (mm)minus02 0 02 04 06 08 1 12

6867N2934N3924N4905N

5886N

7848N

Figure 6 Deflection versus depth test 44

pile increased its impact on the soil-pile reaction was higherThis result can be derived from Figure 6 as well Howevera comparison of the results shown in Figures 7(a) and 7(b)explains the effect of the roughness of the wall pile is moresignificant in soil with the higher relative density Thusthe maximum bending moments were increased about 75and 24 for the relative density of 119863119903 = 70 and 35respectively Figure 8 illustrates the differences in deflectionat ground surface against applied lateral loadings for smoothand rough pile in the loose and dense sand The deflectionsmeasured using LVDTs and those obtained from the integra-tion process (Lines in Figure 8) were in good agreement Theresults indicate that the deflection of the smooth pile locatedin loose sand was 200 larger than the embedded pile inthe dense sand The value of the deflection was increased inrough pile about 175 and 23 for the 119863119903 = 75 and 119863119903 =30 respectively compared to the displacement occurred insmooth pile

As stated to evaluate the load-transfer (p-y) curve thebending moments at each gauge station were computedwith multiplying the strains recorded by the gauge constantmeasured The experimental bending moment data attainedwere fitted with smooth fourth-order polynomial The bend-ing moment curvature M(z) was then double differentiated


0 200 400 600 800 1000

140

120

100

80

60

40

20

0

Late

ral l

oad

(N)

T45T47

Maximum bending moment (Nmiddotcm)

(a)

140

120

100

80

60

40

20

00 200 400 600 800

Late

ral l

oad

(N)

T44T48


(b)

Figure 7 Maximum bending moment versus lateral load (a) 119863119903 =30 (b)119863119903 = 75

and integrated to obtain soil-pile reaction (p) and lateralpile deflection (y) as presented in the following equationsrespectively

119901 =1198892119872(119911)

1198892119911 (5)

119910 = ∬119872(119911)

119864119875119868119875119889119911 (6)

The integration constant was deduced by matching themeasured rotation and deflection at pile head As shown in(7) the p-y curves were obtained by combining the ultimatesoil-pile reaction (119901119906) and the initial horizontal subgrade

0 1 2 3 4 5

Deflection at ground surface (mm)

140

120

100

80

60

40

20

0

Late

ral l

oad

(N)

T45T47

(a)

140

120

100

80

60

40

20

00 1 2 3 4


Late

ral l

oad

(N)

T44T48

(b)

Figure 8 Deflection at ground surface versus lateral load (a) 119863119903 =30 (b)119863119903 = 75

modulus (119896ini) of p-y curve to produce curves for each depthfitted by a hyperbolic relationship of the form

119901 =119910

1119896ini + 119910119901119906 (7)

The results of a typical fitted curve are compared with theexperimental data in Figure 9

Theultimate soil resistance (119901119906)was assumed to be relatedto the square of passive earth pressure coefficient (119896119901 =tan2(45∘ minus 02)) [26] Consider

119901119906

119863= 1198601198962

1199011205741015840119911119899 (8)

where 1205741015840 is effective unit weight of soil (KNm3) 119860 119899 arecurve-fitting constants 119911 is depth of soil (cm) and 119863 ispile diameter (m) 119875119906 was obtained from the p-y curves ateach depth by fitting the experimental data points with arelationship of the form of [8] Linear regression was used toobtain the best-fit values of the nondimensional parameters119860 and 119899 The average values of 119860 were 0093 and 0062 and


08

07

06

05

04

03

02

01

00 004 008 012 016

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

12D 9D

6D

4D

Figure 9 Typical fitted and experimental load-deflection curves indifferent depth for Johor Bahru sandNote (OB observed data Eqfitted curves)

the average values of 119899 were calculated 091 and 117 for denseand loose sand respectively

Load-transfer behavior is also a function of relativedensity of soil A series of tests were conducted at differentrelative densities Figure 10 presents the experimental load-transfer curves for 119863119903 = 75 and 119863119903 = 30 The initialsubgrademodulus was increased with the increasing of depth(Figure 10) The different magnitude of 119896ini for the differentrelative densities is shown in Figure 10 It is found that for agiven load decreasing the relative density causes an increasein the moments and deflections It can be stated that theincrease in deflection in smooth pile was more than that inrough pile

Figure 11 compares the results of experimental 119901-119910 curvesobtained in loose and dense sand at 5D and 6D depths It canbe stated that while there is similar trend in Figures 11(a) and11(b) increasing the friction on the surface the pile had thesignificant influence on the soil-pile reaction As Figures 11(a)and 11(b) show the ratio of dense to loose density soil-pilereaction (119901dense119901loose) ranges from 12 to 20 for the smoothpile at a small displacement and a ratio of 20 at a largedisplacement For the rough pile this ratio ranges from 20to 30 at a small to large displacements It is worth noting thatthis ratio decreasedwhen lateral soil resistance increasedwithdepth However in the smooth piles the initial stiffness ofp-y curves for dense sand was stiffer than that in loose sand(Figure 11)

41 Comparisons with Existing p-y Curves Practically thereare various p-y curves applied now in soil-pile interactionanalysis The procedures for generating p-y curves proposedby Reese et al [15] Weeselink et al [18] and OrsquoNeilland Murchison [16] are widely used in professional jobsThe American Petroleum Institute (InsAPI) suggests thecurve developed by OrsquoNeill and Murchison [16] The modelproposed from this study is presented in Figure 12 andalso compared with the three existing load-transfer curvemodels in dense sand at the depth of 6D (where D is pilediameter) Direct comparison of the p-y curve developedshows significant differences in the magnitude and shapes of

0

01

02

03

04

05

06

07

0 002 004 006 008 01

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

5D-T445D-T48

9D-T449D-T48

(a)

0

01

02

03

04

05

0 002 004 006 008 01 012 014

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

5D-T455D-T47

9D-T459D-T47

(b)

Figure 10 Experimental p-y curves of smooth and rough piles atdifferent depths for Johor Bahru sand (a)119863119903 = 75 (b)119863119903 = 30

the reaction-displacement response with the existing load-transfer curves Initial stiffness of curves for the two silicasand modelsrsquo Reese et al [15] OrsquoNeill and Murchison [16]indicated a perfectly plastic behavior The calcareous sandmodel that is presented by Weeselink et al [18] and the p-ycurves developed here show initial stiffness less than silicasand models In other words although the lateral pressureincreased more gradually but the ultimate soil-pile reactionwas larger than the p-y curves developed in dense sand

Figure 13 illustrates a comparison of the soil-pile reactionfrom the proposed model with the three existing models ata normalized displacement of 119910119863 = 005 It can be seenthat the developed model Reesersquos model and APIrsquos modelhad the same pressure from the surface to depth of 4D Inadditional the proposed model the API model becomesmore stiffer and the Weeselink model becomes more softerwith increasing the depth


04

035

03

025

02

015

01

005

00 005 01 015

6D-T445D-T45

5D-T446D-T45

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

(a)

5D-T47 6D-T47

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

6D-T485D-T48

06

05

04

03

02

01

00 002 004 006 008 01 012 014

(b)

Figure 11 Experimental p-y curves in different relative densitieswith different depthsfor Johor Bahru sand (a) smooth (b) rough

5 Conclusions

A series of model experiments have been conducted insandy soil to determine the load-transfer (p-y) curve andpile behavior subjected to lateral load The p-y curves wereobtained using the strains recorded along the pile located inloose and dense sand The experimental data were fitted bya hyperbolic function as well as several modification factorsin order to consider the soil density and the wall friction ofpile Finally the proposed p-y curves were compared withthe existing p-y curves The following conclusions are drawnbased on this study

(1) The p-y curves developed show good agreement withthe measurements

(2) The soil-pile reaction for various relative density(from 30 to 75) was increased in range from 40

1

09

08

07

06

05

04

03

02

01

00 004 008 012 016 02

ReeseAPIModel-T44

Model-T48Weeselink

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

Figure 12 Comparison of p-y curves obtained with previous studiesat the depth of 6D

0

2

4

6

8

10

12

T45API

WeeselinkReese

0 02 04 06 08

Soil-pile reaction P (KNm)

zD

Figure 13 Newprofiles and existing soil-pile reaction for Johor sandat a strain of 5 (119910119863)

to 95 for smooth pile at a small displacement and90 at a large displacement

(3) The nondimensional parameters in (8) and the aver-age values of 119860 were 0093 and 0062 and the averagevalues of 119899were 091 and 117 for dense and loose sandrespectively

(4) The developed p-y curve shows a significant differ-ence in the magnitude and shape compared with theexisting load-transfer curves


Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The research was undertaken with support from ResearchUniversity Grant (no QJ130000251303H63) under the Uni-versiti TeknologiMalaysia (UTM)Thefirst authorwould liketo thank the Ministry of Education (MOE) and the ResearchManagement Center for the financial supports during thisstudy

References

[1] G Wu and W D L Finn ldquoDynamic nonlinear analysis of pilefoundations using finite element method in the time domainrdquoCanadian Geotechnical Journal vol 34 no 1 pp 44ndash52 1997

[2] M Khari A K Kassim and A Adnan The Effects of Soil-PileInteraction on Seismic Parameters of Superstructure GeomatKuala Lumpur Malaysia 2012

[3] M Khari K A B Kassim and A B Adnan ldquoThe influenceof effective confining pressure on site response analysesrdquo AsianJournal of Earth Sciences vol 4 no 3 pp 148ndash156 2011

[4] M H El Naggar M A Shayanfar M Kimiaei and A AAghakouchak ldquoSimplified BNWF model for nonlinear seismicresponse analysis of offshore piles with nonlinear input groundmotion analysisrdquo Canadian Geotechnical Journal vol 42 no 2pp 365ndash380 2005

[5] M H El Naggar and M Novak ldquoEffect of foundation non-linearity on modal properties of offshore towersrdquo Journal ofGeotechnical Engineering vol 121 no 9 pp 660ndash668 1995

[6] B K Maheshwari K Z Truman M H El Naggar and PL Gould ldquoThree-dimensional nonlinear analysis for seismicsoil-pile-structure interactionrdquo Soil Dynamics and EarthquakeEngineering vol 24 no 4 pp 343ndash356 2004

[7] A M Kaynia and E Kausel ldquoDynamic behaviour of pilegroupsrdquo in Proceedings of the 2nd International Conference onNumerical Methods in Offshore Piling 1982

[8] T Nogami J Otani and H Chen ldquoNonlinear soil-pile inter-action model for dynamic lateral motionrdquo Geotechnical andGeological Engineering vol 118 no 1 pp 89ndash106 1992

[9] M Khari A K kassim andA Adnan ldquoDynamic soil-pile inter-action under earthquake eventsrdquo Caspian Journal of AppliedScienecs Research vol 2 pp 292ndash299 2013

[10] H Matlock ldquoCorrelations for design of laterally loaded pilesin soft clayrdquo in Proceedings of the 2nd Offshore TechnologyConference (OTC rsquo70) vol 1024 pp 577ndash594 Houston TexUSA 1970

[11] M Khari A K Kassim and A Adnan ldquoKinematic bendingmoment of piles under seismic motionsrdquoAsian Journal of EarthSciences In press

[12] B McClelland and J Focht ldquoSoil Modulus for Laterally LoadedPilesrdquo Transactions of the ASCE vol 123 no 2954 pp 1049ndash1086 1958

[13] L Reese W Cox and F Koop ldquoField testing and analysis oflaterally loaded piles in stiff clayrdquo in Proceedings of the 7thOffshore Technology Conference (OTC rsquo75) vol 2312 pp 671ndash690 Houston Tex USA 1975

[14] T W Dunnavant and M W OrsquoNeill Performance Analysisand Interpretation of a lateral load Test of a 72-Inch-DiameterBored Pile in Overconsolidated Clay Report UHCE Universityof Houston 1985

[15] L Reese W Cox and F Koop ldquoAnalysis of Laterally LoadedPiles in Sandrdquo in Proceedings of the 6th Offshore TechnologyConference (OTC rsquo74) vol 2080 Houston Tex USA 1974

[16] M OrsquoNeill and JMurchisonAn Evaluation of P-Y Relationshipsin Sands University of Houston 1983

[17] R L Kondner ldquoHyperbolic stress-strain response cohesivesoilsrdquo Soil Mechanics and Foundations Division vol 89 no 1pp 115ndash144 1963

[18] B DWeeselink J DMurffM F Randolph I L Nunez and AM Hyden ldquoAnalysis of centrifuge model test data from laterallyloaded piles in calcareous sandrdquo in Engineering for CalcareousSediments pp 261ndash270 Balkema RotterdamThe Netherlands1988

[19] G J Dyson and M F Randolph ldquoLoad transfer curves forpiles in calcareous sandrdquo in Proceedings of the InternationalConference on the Behavior of Offshore Structures p 245 258Delft The Netherlands 1997

[20] R F Scott Analysis of Centrifuge Pile Tests Simulation ofPile Driving Reaserch Report OSAPR Project 13 AmericanPetroleum Institute Washington DC USA 1980

[21] API Ed Recommended Practice for Planning Designing andConstructing Fixed Offshore Platforms vol 2 of API Recom-mended Practice American Petroleum Institute 1987

[22] S Narasimha Rao V G S T Ramakrishna and M BabuRao ldquoInfluence of rigidity on laterally loaded pile groups inmarine clayrdquo Journal of Geotechnical and GeoenvironmentalEngineering vol 124 no 6 pp 542ndash549 1998

[23] N K Ovesen ldquoThe scaling law realationship-panel discussionrdquoin Proceedings of the 7th European Conference on Soil Mechanicsand Foundation Engineering pp 319ndash323 Brighton UK 1979

[24] M Khari A K Kassim and A Adnan ldquoSnad sample prepara-tion usingmobile pluviatorrdquoTheArabian Journal for Science andEngineering In press

[25] Y P Vaid and D Negussey ldquoRelatively density of pluviated sandsamplesrdquo Soils and Foundations vol 24 no 2 pp 101ndash105 1984

[26] W G K Fleming A J Weltman M F Randolph and W KElson Piling Engineering Surrey University Press London UK1992

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compression tests to obtain the stress-strain relationshipof soil where the p-y curves by hyperbolic function wereestablished In 1970 Matlock assumed that soil reaction at apoint dependent only on the pile deflection at that point andthe reaction is independence of pile deflection in the depthsof above and below of the point of interest Reese et al [15]developed a p-y curve from the of the full scale load testsThe curve consisted of an initial straight line (119901 = 119896119901119910119911119910 z =desired depth k119901119910 = subgrade modulus) a parabolic section(119901 = 1198621199101119899 119862 = 119901119898119910

1119899

119887 p119898 is soil pressure at y119887) between

119910119887 = 11986360 and 119910119906 = 311986380 (D = pile diameter) and a finalstraight line (119901 = 119860 119904119901119906 119860 119904 = empirical factor p119906 = ultimateresistance derivation from analysis of a wedge) establishedat 119910119906 It is noteworthy that the curve is same for sands inboth above and below the water table Weeselink et al [18]developed p-y curves for use in calcareous soils which is givenbelow as follows

119875 = 119877(119911

1199110)

119899

(119910

119863)

119898

(1)

where 1199110 = constant length taken as 1m R = control variablefor curve stiffness (850 kPa) and m and 119899 are empiricalfactors Other researchers developed the values of119877 119899 and119898[19] In 2001 Dyson and Randolph developed the curves foruse in calcareous soils They added the unit weight factor toWeeselinkrsquos equation Scott [20] performed centrifuge tests toinvestigate the soil-pile interaction and suggested the bilinearfunction to model the p-y curve as presented in the followingequation

119875 =1198631205901015840

0

(1120587) (1sin2119876 + 1(3 minus 4119863))05 (2)

where 12059010158400= (1205901015840

1+ 1205901015840

2+ 1205901015840

3)3

OrsquoNeill and Murchison (1984) studied the p-y curves insand andmodified the suggested equations by Reese et al [15]as shown in the following equation

119875 = 120578119860119875119906 tanh [119896119911119910

119860119875119906] (3)

where 120578 and 119896 are factors for shape of pile (ie for circularcross-section = 1) and initial modulus of subgrade reactionrespectively 119863 is pile diameter and 119911 is the depth 119860 is acoefficient based on loading conditions (static or cyclic) and119875119906 is determined based on wedge type and flow failure whichtakes from the smaller from the following equations

119875119906119889 = 1198623119863119911119910 119875119904119906 = (1198621119911 + 1198622119863) 119911120574 (4)

The three coefficients 1198621 1198622 and 1198623 (as function of the fric-tion angle) are used to calculate the ultimate soil resistanceThe initial modulus of soil reaction is computed using theexperimental factor 119896Thismethod is adopted by the API [21]as amodified shape of the p-y curves for sand for offshore pilefoundations

3 Experimental Work

The schematic diagram of the test setup is shown in Figure 1The dimensions of rectangular soil tank were 900mm inlength 700mm in width and 65mm in height To minimizethe box boundaries effects the size of soil tank was extendedup to 8ndash12D and 3-4D in the direction and perpendicular tolateral load respectively [22] In additional the soil thicknesswas kept below pile tip at least 6D

Lateral load was applied to piles at the surface of themodel ground through a pulley arrangement with flexiblewire attached to pile cap (Figure 1) The other end wasattached to the loading pan The loads were applied bygradually increasing the dead weight in the pan

31 Model Pile and Instrumentation As Figure 2 shows themodel pile wasmade of aluminumalloy tubingwith a value ofYoungrsquos modulus of 698GPa 1588mm in out diameter (119863)and 1388mm in inside diameter The embedded length-to-diameter ratio (119897119863) of pile was equal to 32The pile diameterwas around 16 times greater than the maximum particle sizefor sand which satisfied the recommended ratios in excess of15ndash30 to avoid scale effects [23] The properties of the modelpile were scaled by a dimensional analysis (Buckingham Pitheorem) with the properties of the basic prototype pile ofPenang Second Crossing in Malaysia A steel plate was usedas a pile cap for the single pile To satisfy the fixed headconditions the pile was passed through a hole in the capand then screwed to angle profiles (length = 50mm) weldedon the hole (Figure 2) The tests were conducted on smooth(wall friction of pile was low) and rough (fine sandwas pastedaround the pile by adhesive) single piles in dense (119863119903 = 75)and loose (119863119903 = 30) sand

A typical test (shown in Figure 1) included nine instru-ments two linear variable differential transducer (LVDT) tomeasure the deflection of the pile and seven levels of electricalstrain gauges having resistance of 350 plusmn 01Ω to measurebending moments The strain gauges were fixed along theouter surface of the pile The distances of the gauges were atcloser and larger spacing near ground surface and towardsthe pile tip respectively (Figure 2) They were coated with a05mm thick layer of epoxy for protection

Gauge constants were calculated for every one of thegauges separately The pile was supported on a set of edgesFifteen different pure moments were applied over the centralportion of pile (Figure 2) The values of observed strainand applied moments were correlated to compute the gaugeconstant at each gauge location (Figure 3) The constantwas determined by means of the method of least squaresDuring the calibration the central deflection of pile wasobserved The flexural stiffness (EI) was computed to be91 times 10

6Nsdotmm2

32 Soil Properties and Sample Preparation The tests con-ducted on the dried sand (ie in the laboratory temperature)The soil samples were from Johor Bahru in Malaysia Thesampled sand was classified as SP according to the UnifiedSoil Classification System (USCS) The medium diameter



LVDT

Straingauges

Johor Bahru sand

65 cm

90 cm

Pulley

Flexible wire

Loadingpan






G1 G2 G3 G4 G5 G6 G7

Load

(a)

700

600

500

400

300

200

100

0

0 100 200 300 400 500 600


omen

t (Nmiddotcm

)(b)


0

20

40

60

80

100

001 01 1 10

Perc

ent fi

ner

Particle size (mm)





1

2

3









0

5

10

15

20

25

30

35

40

Dep

th (c

m)


6867N2934N3924N4905N

5886N

7848N





0 200 400 600 800 1000

140

120

100

80

60

40

20

0

Late

ral l

oad

(N)

T45T47


(a)

140

120

100

80

60

40

20

00 200 400 600 800

Late

ral l

oad

(N)

T44T48


(b)



119901 =1198892119872(119911)

1198892119911 (5)

119910 = ∬119872(119911)

119864119875119868119875119889119911 (6)


0 1 2 3 4 5


140

120

100

80

60

40

20

0

Late

ral l

oad

(N)

T45T47

(a)

140

120

100

80

60

40

20

00 1 2 3 4


Late

ral l

oad

(N)

T44T48

(b)



119901 =119910

1119896ini + 119910119901119906 (7)



119901119906

119863= 1198601198962

1199011205741015840119911119899 (8)



08

07

06

05

04

03

02

01

00 004 008 012 016

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

12D 9D

6D

4D






0

01

02

03

04

05

06

07

0 002 004 006 008 01

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

5D-T445D-T48

9D-T449D-T48

(a)

0

01

02

03

04

05

0 002 004 006 008 01 012 014

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

5D-T455D-T47

9D-T459D-T47

(b)





04

035

03

025

02

015

01

005

00 005 01 015

6D-T445D-T45

5D-T446D-T45

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

(a)

5D-T47 6D-T47

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

6D-T485D-T48

06

05

04

03

02

01

00 002 004 006 008 01 012 014

(b)


5 Conclusions




1

09

08

07

06

05

04

03

02

01

00 004 008 012 016 02

ReeseAPIModel-T44

Model-T48Weeselink

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)


0

2

4

6

8

10

12

T45API

WeeselinkReese

0 02 04 06 08


zD








Acknowledgments


References





























RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation











LVDT

Straingauges

Johor Bahru sand

65 cm

90 cm

Pulley

Flexible wire

Loadingpan






G1 G2 G3 G4 G5 G6 G7

Load

(a)

700

600

500

400

300

200

100

0

0 100 200 300 400 500 600


omen

t (Nmiddotcm

)(b)


0

20

40

60

80

100

001 01 1 10

Perc

ent fi

ner

Particle size (mm)





1

2

3









0

5

10

15

20

25

30

35

40

Dep

th (c

m)


6867N2934N3924N4905N

5886N

7848N





0 200 400 600 800 1000

140

120

100

80

60

40

20

0

Late

ral l

oad

(N)

T45T47


(a)

140

120

100

80

60

40

20

00 200 400 600 800

Late

ral l

oad

(N)

T44T48


(b)



119901 =1198892119872(119911)

1198892119911 (5)

119910 = ∬119872(119911)

119864119875119868119875119889119911 (6)


0 1 2 3 4 5


140

120

100

80

60

40

20

0

Late

ral l

oad

(N)

T45T47

(a)

140

120

100

80

60

40

20

00 1 2 3 4


Late

ral l

oad

(N)

T44T48

(b)



119901 =119910

1119896ini + 119910119901119906 (7)



119901119906

119863= 1198601198962

1199011205741015840119911119899 (8)



08

07

06

05

04

03

02

01

00 004 008 012 016

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

12D 9D

6D

4D






0

01

02

03

04

05

06

07

0 002 004 006 008 01

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

5D-T445D-T48

9D-T449D-T48

(a)

0

01

02

03

04

05

0 002 004 006 008 01 012 014

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

5D-T455D-T47

9D-T459D-T47

(b)





04

035

03

025

02

015

01

005

00 005 01 015

6D-T445D-T45

5D-T446D-T45

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

(a)

5D-T47 6D-T47

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

6D-T485D-T48

06

05

04

03

02

01

00 002 004 006 008 01 012 014

(b)


5 Conclusions




1

09

08

07

06

05

04

03

02

01

00 004 008 012 016 02

ReeseAPIModel-T44

Model-T48Weeselink

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)


0

2

4

6

8

10

12

T45API

WeeselinkReese

0 02 04 06 08


zD








Acknowledgments


References





























RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










1

2

3









0

5

10

15

20

25

30

35

40

Dep

th (c

m)


6867N2934N3924N4905N

5886N

7848N





0 200 400 600 800 1000

140

120

100

80

60

40

20

0

Late

ral l

oad

(N)

T45T47


(a)

140

120

100

80

60

40

20

00 200 400 600 800

Late

ral l

oad

(N)

T44T48


(b)



119901 =1198892119872(119911)

1198892119911 (5)

119910 = ∬119872(119911)

119864119875119868119875119889119911 (6)


0 1 2 3 4 5


140

120

100

80

60

40

20

0

Late

ral l

oad

(N)

T45T47

(a)

140

120

100

80

60

40

20

00 1 2 3 4


Late

ral l

oad

(N)

T44T48

(b)



119901 =119910

1119896ini + 119910119901119906 (7)



119901119906

119863= 1198601198962

1199011205741015840119911119899 (8)



08

07

06

05

04

03

02

01

00 004 008 012 016

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

12D 9D

6D

4D






0

01

02

03

04

05

06

07

0 002 004 006 008 01

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

5D-T445D-T48

9D-T449D-T48

(a)

0

01

02

03

04

05

0 002 004 006 008 01 012 014

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

5D-T455D-T47

9D-T459D-T47

(b)





04

035

03

025

02

015

01

005

00 005 01 015

6D-T445D-T45

5D-T446D-T45

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

(a)

5D-T47 6D-T47

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

6D-T485D-T48

06

05

04

03

02

01

00 002 004 006 008 01 012 014

(b)


5 Conclusions




1

09

08

07

06

05

04

03

02

01

00 004 008 012 016 02

ReeseAPIModel-T44

Model-T48Weeselink

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)


0

2

4

6

8

10

12

T45API

WeeselinkReese

0 02 04 06 08


zD








Acknowledgments


References





























RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










0 200 400 600 800 1000

140

120

100

80

60

40

20

0

Late

ral l

oad

(N)

T45T47


(a)

140

120

100

80

60

40

20

00 200 400 600 800

Late

ral l

oad

(N)

T44T48


(b)



119901 =1198892119872(119911)

1198892119911 (5)

119910 = ∬119872(119911)

119864119875119868119875119889119911 (6)


0 1 2 3 4 5


140

120

100

80

60

40

20

0

Late

ral l

oad

(N)

T45T47

(a)

140

120

100

80

60

40

20

00 1 2 3 4


Late

ral l

oad

(N)

T44T48

(b)



119901 =119910

1119896ini + 119910119901119906 (7)



119901119906

119863= 1198601198962

1199011205741015840119911119899 (8)



08

07

06

05

04

03

02

01

00 004 008 012 016

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

12D 9D

6D

4D






0

01

02

03

04

05

06

07

0 002 004 006 008 01

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

5D-T445D-T48

9D-T449D-T48

(a)

0

01

02

03

04

05

0 002 004 006 008 01 012 014

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

5D-T455D-T47

9D-T459D-T47

(b)





04

035

03

025

02

015

01

005

00 005 01 015

6D-T445D-T45

5D-T446D-T45

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

(a)

5D-T47 6D-T47

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

6D-T485D-T48

06

05

04

03

02

01

00 002 004 006 008 01 012 014

(b)


5 Conclusions




1

09

08

07

06

05

04

03

02

01

00 004 008 012 016 02

ReeseAPIModel-T44

Model-T48Weeselink

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)


0

2

4

6

8

10

12

T45API

WeeselinkReese

0 02 04 06 08


zD








Acknowledgments


References





























RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










08

07

06

05

04

03

02

01

00 004 008 012 016

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

12D 9D

6D

4D






0

01

02

03

04

05

06

07

0 002 004 006 008 01

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

5D-T445D-T48

9D-T449D-T48

(a)

0

01

02

03

04

05

0 002 004 006 008 01 012 014

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

5D-T455D-T47

9D-T459D-T47

(b)





04

035

03

025

02

015

01

005

00 005 01 015

6D-T445D-T45

5D-T446D-T45

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

(a)

5D-T47 6D-T47

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

6D-T485D-T48

06

05

04

03

02

01

00 002 004 006 008 01 012 014

(b)


5 Conclusions




1

09

08

07

06

05

04

03

02

01

00 004 008 012 016 02

ReeseAPIModel-T44

Model-T48Weeselink

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)


0

2

4

6

8

10

12

T45API

WeeselinkReese

0 02 04 06 08


zD








Acknowledgments


References





























RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










04

035

03

025

02

015

01

005

00 005 01 015

6D-T445D-T45

5D-T446D-T45

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

(a)

5D-T47 6D-T47

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)

6D-T485D-T48

06

05

04

03

02

01

00 002 004 006 008 01 012 014

(b)


5 Conclusions




1

09

08

07

06

05

04

03

02

01

00 004 008 012 016 02

ReeseAPIModel-T44

Model-T48Weeselink

Soil-

pile

reac

tion

(KN

m)

Deflection (yD)


0

2

4

6

8

10

12

T45API

WeeselinkReese

0 02 04 06 08


zD








Acknowledgments


References





























RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation












Acknowledgments


References





























RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation











RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation









Documents

Research Article Development of Curves of Laterally Loaded Piles in Cohesionless …downloads.hindawi.com/journals/tswj/2014/917174.pdf · 2019-07-31 · Research Article Development