47

Transportation Research Record: Journal of the Transportation Research Board, No. 2363, Transportation Research Board of the National Academies, Washington, D.C., 2013, pp. 47–55.DOI: 10.3141/2363-06

College of Engineering, Florida Institute of Technology, Melbourne, FL 32901. Corresponding author: F. Jarushi, fjarushi@yahoo.com.

at its highest fuel setting or at a setting determined by the engineer with a limit of 0.25-in. rebound per blow. For this research, HPR was defined as any rebound exceeding the specified 0.25-in. limit.

The objective of this research was to develop a geotechnical engineering protocol that would help engineers anticipate HPR.

Literature review

Authier and Fellenius (2) and Likins (3) presented information on high quake for several locations. High quake is the modeling param-eter describing the soil’s initial elastic movement from the energy of a single hammer blow. High quake may be related to HPR; there-fore, the case studies documenting high quake are included and summarized in Table 1.

Hussein et al. reported HPR during driving, at a site where FL-528 crosses the Indian River in Brevard County, Florida (4). Prestressed concrete piles (PCPs), 30 in. square and 115 ft long with an 18-in. hollow core, were driven by a single-acting Raymond 8/0 air hammer. Rebound between 0.5 and 0.8 in. was recorded with PDA equipment, when the pile encountered soils composed of medium-dense silt with sand to silty sand underlain by firm-to-hard clayey sand to sandy clay.

Murrell et al. reported HPR, which was termed “bouncing,” dur-ing driving of PCPs 20 in. square and 70 ft long with a single-acting diesel hammer (5). The site was located in coastal North Carolina, and the HPR soils consisted of firm-to-stiff clay underlain by dense-to-very-dense sand. Cone penetrometer pore water pressures (u2) greater than 20 tons/ft2 were recorded during the soil investigation in the HPR soils. In summary, the following trends were observed:

• Piles were high displacement,• Soils in the rebound layers contained material passing a No. 200

sieve with the exception of Site 2 in Likins (3),• Soils in the rebound zone were saturated and stiff to hard or

dense to very dense, and• Pile-driving hammers were generally single acting.

testing Program

HPR was evaluated at six Florida DOT sites. Five of the sites are in the Central Florida area, while the sixth site is in the Florida Panhandle. An extensive field and laboratory testing program was performed from 2008 to 2010 at three of the six Florida DOT sites referred to as retesting sites, where additional geotechnical field data were collected after completion of construction. The field testing

Prediction of High Pile Rebound with Fines Content and Uncorrected Blow Counts from Standard Penetration Test

Fauzi Jarushi, Paul J. Cosentino, and Edward H. Kalajian

High-displacement piles have rebounded significantly while undergoing an extremely small permanent set per hammer blow in certain soils. This phenomenon, called high pile rebound (HPR), has occurred in many areas of North America. The Florida Department of Transporta-tion identified HPR at six sites in Florida during the process of driving square, precast, prestressed concrete piles into saturated, fine silty-to-clayey sand and sandy-clay soils. Data on pile driving analyzer deflec-tion versus time were used to develop strong correlations between fines content, uncorrected standard penetration test blow counts (NSPT), pile displacements, and rebound. The correlations developed in this study allow the geotechnical engineer to predict whether HPR will occur at a proposed site at which high-displacement piles are planned for driving by a single-acting diesel hammer. A design equation relating pile rebound to NSPT and fines content was developed. The correlations showed that permanent set and rebound were a direct function of NSPT and fines con-tent of the soil at the pile tip. The design equation provides a methodology that allows prediction of HPR during the design phase.

Contractors and engineers have experienced pile installation prob-lems while driving high-displacement piles with single-acting diesel hammers at Florida Department of Transportation (DOT) construc-tion sites in the Central and Panhandle regions of Florida (1). Prob-lems occur during pile driving when a large initial penetration per hammer blow is followed by a large elastic rebound [termed high pile rebound (HPR)] resulting in a small or negligible permanent set per blow. Figure 1 illustrates a typical HPR record of pile-top displace-ment versus time for a single hammer blow obtained from strain gauges and accelerometers of the pile-driving analyzer (PDA). The maximum initial downward motion (DMX) is the sum of elastic and plastic deformations of the pile and soil system. The final displace-ment is the pile penetration per blow, or “set.” “Rebound” is the difference between the pile maximum displacement and final set.

HPR may prevent the required driving resistance from being achieved or stop the pile-driving process, placing the foundation performance at risk or requiring redesign. HPR problems gener-ally occurred in soils that did not display any unusual geotechnical properties during routine soil investigations (1).

Florida DOT Specification 455-5.10.3 for road and bridge construc-tion defines “refusal” as 20 blows per in. with the hammer operating

48 Transportation Research Record 2363

included standard penetration test (SPT) borings with N-values, unconfined compressive tests from a pocket penetrometer, cone penetrometer, Pencel Pressuremeter tests, and dilatometer sound-ings to produce liftoff pressures and elastic moduli. The lab work included tests on disturbed samples to determine natural moisture content, grain size, and hydrometer data and Atterberg limits. Per-meability and consolidated undrained triaxial testing parameters were evaluated by using undisturbed samples. The data from the retesting program for the three sites appear in Cosentino et al. (1).

Findings from the retesting program indicated that the most critical parameters associated with HPR were percentage of fines and uncor-rected SPT blow counts (NSPT) or corrected blow counts (N60) (1). The fines content is defined as the percentage passing a No. 200 sieve. Cone penetrometer pore water pressure was also an indicator of HPR. The authors are currently evaluating cone penetrometer pore water pressure at these HPR sites.

Existing geotechnical profile data were used at the other three sites. PDA data were available from the pile-driving record at all the sites. The fines content, NSPT, and PDA data from all six Florida DOT sites were determined and compared.

PDA data were used to evaluate the pile movement per blow and to identify HPR limits and trends. The PDA software output included the following:

• The pile depth or elevation corresponding to each hammer blow,• The maximum displacement of the pile at the end of each

record (i.e., DMX in the PDA output), and• The permanent set of the pile (i.e., set in the PDA output from

the inspector’s log).

The PDA time scale is typically shorter or longer than the time that the piles actually move after each hammer blow. The digital maxi-mum displacements and inspector set were subtracted to determine the rebound per hammer blow (i.e., DMX − set = rebound).

Plots were developed for each of the Florida DOT sites to relate elevations (based on North American Vertical Datum 1988) to DMX, set, and rebound from the PDA data. The plots (Figures 2 to 7) include a dashed vertical line at 0.25-in. rebound that is based on the Florida DOT specification. The elevation associated with the start of the PDA data corresponded to the depth below ground surface at which pile driving commenced because piles at these sites were set into predrilled holes. Soil logs for the sites, NSPT, and fines content are also presented in Figures 2 to 7.

soiL ProfiLes and ProPerties

The soil profiles at the HPR sites appear in Figures 2 to 7. The soils at these sites were mainly sand with varying percentages of silts and clays. At all sites, the water table was located above the elevation at which HPR occurred. HPR sites and associated rebound with eleva-tions are presented in Table 2, which also presents soil classification, Atterberg limits, natural moisture content, and average fines content of the soils. The authors categorized HPR at two levels: (a) unaccept-able rebound, with minimal or near-zero set, and (b) acceptable rebound, at which set was sufficiently large that continual pile penetration occurred.

Soils at the soil strata where HPR occurred can be classified as one of the following groups: SC (clayey sand), SM-SC (silty clay with fine sand), SM (silty sand), CL (clay with some shell), SP-SM (sand with silt), SP-SC (poorly graded sand with clayey sand), and CH (green clay). Most HPR layers had high fines con-tent with a natural moisture content less than the liquid limit. These soils plotted near the A-line on the Casagrande plasticity chart. These soils were olive green to light green, with visual descriptions ranging from clayey and silty fine sands to highly plastic clays.

PiLe-driving oPerations

A summary of pile-driving information obtained from the case his-tories is presented in Table 3. It includes information such as site description, pile description, predrilled depth, hammer characteristic,

Set

Rebound

Time

Dis

pla

cem

ent

Dmax

FIGURE 1 Typical data for pile top displacement versus time from one hammer blow.

TABLE 1 High-Quake Case Histories

Author Site Description Pile Type ShapePile Length (ft)

Hammer Type and Model

Toe Quake (in.) Soil Description

Authier and Fellenius (2)

Ontario, Canada Closed-toe pipe piles 12.75-in. O.D.

41 Drop and three diesel 0.1–0.78 Very dense sandy silty glacial till

Montreal, Canada 12-in. square PCP 41 Berminghammer B-400 open-end diesel

0.8 Dense clayey silty glacial till

Likins (3) Site 1 Seattle, Washington

24-in.-dia. octagonal PCP 70 Kobe K45 open-ended diesel

0.42 Hard silty clay

Site 2 Florida

24-in. square PCP 122 Raymond 8/0 single-acting air

0.7 Dense light gray sand

Site 3 Florida

18-in. square PCP 80 Delmag D-30 diesel 0.4–0.5 Dense fine sand with some silt or clay

Note: O.D. = outer diameter; dia. = diameter.

Jarushi, Cosentino, and Kalajian 49

FIGURE 2 Anderson Street overpass: (a) generalized soil profile for 104-ft elevation of soil layers, (b) PDA diagram with pile displacements and rebound (in.), (c) NSPT in blows per foot, and (d) percentage of fines content (GWT = groundwater table).

(a)

(b)

(c) (d)

FIGURE 3 I-4–John Young Parkway: (a) generalized soil profile for 96-ft elevation of soil layers, (b) PDA diagram with pile displacements and rebound (in.), (c) NSPT in blows per foot, and (d) percentage of fines content.

(a)

(b)

(c) (d)

50 Transportation Research Record 2363

FIGURE 4 SR-50–SR-436 overpass: (a) generalized soil profile for 99-ft elevation of soil layers, (b) PDA diagram with pile displacements and rebound (in.), (c) NSPT in blows per foot, and (d) percentage of fines content (EB = eastbound, WB = westbound).

(a)

(b)(c) (d)

FIGURE 5 I-4–US-192, Ramp BD: (a) generalized soil profile for 89-ft elevation of soil layers, (b) PDA diagram with pile displacements and rebound (in.), (c) NSPT in blows per foot, and (d) percentage of fines content.

PredrilledDepth

(a)

(b)

(c) (d)

Jarushi, Cosentino, and Kalajian 51

FIGURE 6 I-4–SR-408, Ramp B: (a) generalized soil profile for 105-ft elevation of soil layers, (b) PDA diagram with pile displacements and rebound (in.), (c) NSPT in blows per foot, and (d) percentage of fines content.

(a)

(b)

(c)(d)

FIGURE 7 Ramsey Branch Bridge: (a) generalized soil profile for 7-ft elevation of soil layers, (b) PDA diagram with pile displacements and rebound (in.), (c) NSPT in blows per foot, and (d) percentage of fines content.

(a)

(b)(c)

(d)

52 Transportation Research Record 2363

driving-blow counts, cushion thickness, and maximum rebound and elevation. As the information suggests, the HPR sites had several common characteristics:

• Piles were square displacement and ranged between 18 and 24 in.,

• Tested and production piles were longer than 70 ft,• Piles were set into predrilled holes of varying depths,• Pile-driving hammers were single acting, and• Average counts of pile-driving blows in the rebound layers

were greater than 50 blows per foot.

resuLts and discussion

Each site was analyzed by relating rebound, DMX, and set to NSPT and fines content versus elevation.

site 1. anderson street overpass

The HPR problems that occurred during installation of piles at Pier 6 of Site 1 caused construction delays, and the foundations were redesigned and replaced with low-displacement steel H-piles

TABLE 2 Rebound, Elevation, and Soil Properties at HPR Sites

SiteRetesting Site Rebound Observed Elevationa (ft) Soil Type (USCS) FC (%) wn (%) LL (%) PI (%)

I-4–SR-408, Anderson Yes No 74 to 15 SP-SM, SM, CL, SM-SC <20 22–50 47 18 Street overpass Yes, unacceptable 15 to −10 SM-SC, SC, CL, CH >40 30–50 40–86 13–42

I-4–John Young Yes Yes, acceptable 80 to 70 SP-SM >40 23 30 8No 70 to 20 SM, SC, CL, CH 20 31 61 42Yes, unacceptable 20 to 0 SM >40 25 34 7

SR-50–SR-436 overpass No Yes, acceptable 60 to 45 SP and SM 20 24 NA NANo 45 to 28 CH, SM, SP 30 53 NA NAYes, unacceptable 28 to 17 CH >40 63 155 110

I-4–US-192, Ramp BD No Yes, acceptable 62 to 53 SP 25 48 NP NPNo 53 to 25 SM, SC 25 42 38 19Yes, unacceptable 25 to 0 CH and ML >40 45 63 37

I-4–SR-408, Ramp B No No 90 to 35 SP, SP-SM, SP-SC, CH 20 29 NP NPYes, acceptable 35 to 9 SC 20 23 NA NA

Ramsey Branch Bridge Yes No 7 to −28 SP-SM <20 36 NP NPYes, unacceptable −28 to −70 SP-SC and SC >40 38 45 25

Note: USCS = Unified Soil Classification System; FC = fines content; wn = natural moisture content; LL = liquid limit; PI = plasticity index; NA = not available; NP = nonplastic.aNAVD elevations.

TABLE 3 Piles and Hammers

Site Pile Size and Type

Pile Length (ft)

Predrilled Depth (ft)

Hammer Model Typea

Ram Weight (kips)

Hammer Rate Energy (ft-kip)

Average BLb

(blows/ft) Total BLc

Rebound Elevation (ft)

Maximum Rebound (in.)

Anderson Street overpass

24-in. square SPCP 70–124 30 Delmag D62-22

13.67 90 135 3,674 15 to −10 1.4

HP (14 × 89; 26.1 in. square)

120 30 ICE I-30 6.6 71 NA NA — No rebound

I-4–John Young 24-in. square PCP 90–110 16 ICE 120 S 12 120 53 1,398 20 to 0 2.1

SR-50–SR-436 overpass

24-in. square PCP 105 32 APE 62-42

13.7 154 143 526–2,599 26 to 17 1.1

I-4–US-192, Ramp BD

24-in. square PCP 95 25 ICE 120 S 12 120 195 1,030 30 to 20 0.7–1.5

I-4–SR-408, Ramp B

18-in. square PCP 100 14 Delmag D36-32

7.94 84 50 3,101 30 to 0 0.5

Ramsey Branch Bridge

18-in. square PCP 100 NA Vulcan 512 Air

12 60 110 3,054 −28 to −70 1.2

Note: Cushion thickness varied from 9 to 12 in.; BL = blow counts; NA = not available.aSingle acting.bAverage driving blow counts in the rebound layer.cTotal pile-driving blow counts.

Jarushi, Cosentino, and Kalajian 53

(HP 14 × 89). While a PCP test pile 110 ft long and 24 in. square was being driven at Pier 6, HPR occurred and was evaluated by using PDA data. As Figure 2b shows, the PDA rebound ranged between 0.25 and 1 in. beginning at Elevation 15 ft to the end of driving at Eleva-tion −7 ft. The overlying non-HPR zone, where the pile experienced less than 0.25 in. of rebound, extended from Elevations 74 to 15 ft. In this zone, sets were sufficiently large that continual pile penetration occurred. In the HPR zone, where rebound approached DMX, rebound up to 1 in. occurred in this lower zone, Elevations 15 to −6 ft, which included a high pile blow count of 2,330 with minimal or zero set.

The NSPT from Test Boring AS-103, which was closest to Pier 6, was used for this evaluation. At Elevation 15 ft, where the pile rebound started, the average NSPT increased from 15 to 50 blows per foot (Figure 2c) and the fines content increased from 14% to 40% (Figure 2d). These higher NSPT and fines content are associated with an increase in rebound of up to 1 in. and a decrease in permanent set to near zero as Figure 2b shows.

site 2. i-4–John Young Parkway

At Site 2, as Figure 3b shows, HPR was observed in two zones: Elevations 80 to 70 ft and below Elevation 20 ft. At Elevations 80 to 70, the NSPT reached a maximum of 35 blows per foot when rebound reached 0.75 in. At HPR zone Elevations 20 to 5 ft, the NSPT increased to more than 50 blows per foot followed by an increase in rebound to more than 2 in. and a decrease in both the DMX and permanent set. The data below Elevation 20 ft included 980 pile hammer blows, again indicating a decrease in DMX and perma-nent set. The fines content shown in Figure 3d reached 70% at the same elevations at which rebound increased and corresponded to a decrease in pile displacements.

site 3. sr-50–sr-436 overpass

As Figure 4b shows, HPR was observed in two zones at Site 3: an upper elevation between 60 and 45 ft and a lower elevation from 28 ft continuing to the end of driving. A comparison of the PDA output with NSPT and fines content, in the upper HPR zone, shows the NSPT increased from 18 to 50 blows per foot and the fines content increased from 10% to 20%. In the lower HPR zone, Elevations 28 to 17 ft, a maximum rebound of 1 in. and a significant decrease in both DMX and permanent set occurred when the NSPT increased from 18 to 70 blows per foot. In this lower region, the soils changed from SM to CH, as the fines content reached 60%.

site 4. i-4–us-192, ramp Bd

At Site 4, HPR occurred at two elevations as Figure 5b shows: an upper zone, Elevations 62 to 53 ft, and a lower zone, Elevations 25 ft to the end of driving. Piles at this site with tip elevations between 25 and 0 ft experienced rebound ranging between 0.4 and 1 in. per hammer blow when the NSPT increased from 15 to more than 50 blows per foot. Rebound of 0.4 in., followed by an accept-able permanent set, was encountered between Elevations 62 and 53 ft when the NSPT were 30 blows per foot and the fines content was more than 30%. As the NSPT and fines content decreased between Elevations 50 and 25 ft, the rebound decreased to less than 0.25 in.

and permanent set increased. Below Elevation 25, both the NSPT and fines content increased approximately linearly with rebound.

A second PDA test pile was driven at this site. The data for this pile are not presented; however, the second test pile experienced similar rebound (0.75 to 1.5 in.) between Elevations 25 and 0 ft.

site 5. i-4–sr-408, ramp B

As the PDA data for Site 5 show (Figure 6b), no rebound was observed above Elevation 35 ft when the average NSPT were 8 blows per foot and the fines content was generally less than 20%, with the exception of clayey-fines sand (SC) overlying a thin CH layer (Elevations 45 to 42 ft) with a fines content of 45%. Rebound exceed-ing 0.25 in. was observed between Elevations 35 to 11 ft when the NSPT increased from an average of 8 to 25 blows per foot while the fines content was an average of 20%. This increase in NSPT, accompanied by fines content of approximately 20%, produced a maximum rebound of 0.35 in. and acceptable permanent set. Between Elevations 12 and 10 ft, the NSPT increased to 50 blows per foot with a fines content of 20%, yielding a maximum rebound of 0.5 in. and a decrease in permanent set. The soil conditions at this site were such that driving produced sufficient permanent set with minor HPR.

site 6. ramsey Branch Bridge

PDA information at Site 6 was not available above Elevation −22 ft. According to inspector logs, the pile did not experience any HPR above that elevation. Rebound occurred below Elevation −28 when the NSPT increased from 3 to more than 15 blows per foot and the fines content increased 40%.

As Figure 7b shows, HPR occurred when the pile penetrated into soils containing medium-dense greenish-gray and brown sand with silt (SP-SC) to greenish-gray clayey sand with cemented sand (SC). Although HPR of more than 1 in. occurred, the pile driving produced sufficient permanent set to allow the design capacities to be met.

correLations Between HPr, NsPt, and fines content

The data at the six sites were examined to develop correlations between (a) the pile displacements of set and rebound and (b) both NSPT and fines content. Acceptable permanent set for the piles occurred in soil conditions for which NSPT were 15 blows per foot or lower with fines content of 25%. Rebound in these soils, less than Florida DOT’s limit of 0.25 in., yielded permanent set of up to 3 in. When NSPT was between 15 and 40 blows per foot with fines content of 25% to 40%, the pile rebound varied between 0.25 and 0.6 in., accompanied by an acceptable permanent set. As NSPT exceeded 40 blows per foot with fines content greater than 40%, pile rebound was greater than 0.6 in. and accompanied by a small or zero per-manent set. These correlations, shown in Figure 8, a and b, were developed on the basis of the averages obtained within HPR zones (>0.25 in.) and non-HPR zones (<0.25 in.).

Data from Hussein et al. were added to the data from the six sites (4). The latter data were developed from the PDA results for the test pile chosen for the SR-528 bridge over the Indian River. The rebound versus NSPT produced an increasing nonlinear polynomial equation

54 Transportation Research Record 2363

with a regression coefficient, R2, of .80. NSPT greater than 15 blows per foot were associated with HPR of greater than 0.25 in. Blow counts greater than 50 blows per foot, the practical refusal limit, were esti-mated by linearly extrapolating the recorded data to equivalent blows-per-foot values (e.g., 30 blows per 0.5 ft = 60 blows per foot). The rebound-versus-fines content also produced a nonlinear polynomial equation with R2 of .80, indicating a significant increase in rebound as fines content exceeded about 25%. Neither permanent set versus NSPT nor fines content produced desirable correlations. The data (Figure 8b) indicate that set decreased with increases in either NSPT or fines content, but at low blow counts and fines content, scatter is large.

The authors also developed correlations between rebound and corrected N60. Both uncorrected NSPT and corrected N60 versus rebound produced a similar nonlinear polynomial equation with R2 of .80. The uncorrected NSPT was chosen for use so that engineers could more easily correlate behavior to field data from other sites.

The combined data from this study and from the site presented by Hussein et al. showed consistent trends to indicate that HPR may occur for (4)

• High-displacement piles,• Piles driven with single-acting diesel hammers,

• Pile tip below groundwater table,• Soils with high fines content, and• Soils with high NSPT values.

Correlations using NSPT and fines content from the seven sites, including the one in Hussein et al., were used to develop a design equation to predict pile rebound. Equation 1 was obtained through a statistical analysis of the data by using SPSS software (4). An analysis of variance (ANOVA) was conducted to determine whether a signifi-cant relationship existed between rebound and NSPT and fines content. The ANOVA result from SPSS gave an extremely strong indication of significance and produced the regression equations and R2 values shown in Figure 8. These results were further validated by examina-tion of the experimental residuals, which appeared normally distrib-uted and showed no signs of any patterns that would cause concern. Because of these data, there was no reason to question the results of the ANOVA, and thus the regression equations from these are presented.

Equation 1 is for use in predicting the rebound behavior of square, high-displacement, 18-in.-or-larger concrete piles driven by single-acting diesel hammers.

R N= − + +0.166 0.016 0.009FC (1)SPT

(a)

(b)

FIGURE 8 Correlation between (a) rebound, NSPT, and fines content and (b) permanent set, NSPT, and fines content.

Jarushi, Cosentino, and Kalajian 55

where

R = rebound (in.); NSPT = uncorrected SPT blow counts (blows per foot), five blows

per foot or higher; and FC = fines content (percentage), 12% or higher.

The applicability of Equation 1 was evaluated by plotting the predicted rebound versus actual rebound, with the data from the seven sites used in this study and an additional five HPR Florida DOT sites. As Figure 9 shows, the equation produced R2 values of .80, which indicates an ability to predict rebound by using NSPT and fines content.

ConClusions and ReCommendations

Plots were developed to show that rebound correlates to both NSPT and fines content while permanent set did not correlate well to either variable. An equation for predicting rebound, based on SPT blow counts and fines content, was developed, and the results showed a good correlation with actual results.

When NSPT was less than 15 blows per foot and fines content less than 25%, rebound was less than 0.25 in., yielding acceptable per-manent set of up to 3 in. For NSPT values between 15 and 40 blows

per foot and fines content of 25% to 40%, the pile rebound varied between 0.25 and 0.6 in., yielding acceptable permanent set values. For cases in which NSPT exceeded 40 blows per foot with fines con-tent greater than 40%, pile rebound was greater than 0.6 in. and was accompanied by unacceptable permanent set.

The results of this study confirm that HPR occurs with high-displacement piles driven with single-acting diesel hammers into saturated medium-dense to very dense or stiff to hard soils. It is recommended that the geotechnical engineer use this methodol-ogy to assess HPR potential if large-displacement piles are under consideration.

aCknowledgments

This research was completed under a Florida DOT contract. The authors acknowledge the following people for their assistance: Peter Lai, David Horhota, Kathy Gray, Brian Bixler, Todd Britton, and Sam Weede of the Florida Department of Transportation; Zan Bates of Ardaman & Associates; and Mohamad Hussein, Brian Mondelo, and Ryan Gissel of GRL Engineers, Inc. The authors especially thank Thaddeus J. Misilo, Yeniree Chin Fong, and Katie Davis—students at the Florida Institute of Technology—who made this project successful.

RefeRenCes

1. Cosentino, P., E. Kalajian, T. Misilo, Y. Chin Fong, K. Davis, F. Jarushi, A. Bleakley, M. H. Hussein, and Z. Bates. Design Phase Identifica-tion of High Pile Rebound Soils. Florida Department of Transportation, Tallahassee, 2010.

2. Authier, J., and B. H. Fellenius. Quake Values Determined from Dynamic Measurements. Proc., 1st International Conference on the Application of Stress-Wave Theory on Piles. A. A. Belkema, Stockholm, Sweden, 1980, pp. 197–216.

3. Likins, G. E. Pile Installation Difficulties in Soils with Large Quakes. Proc., Symposium 6 at ASCE Convention, Philadelphia, Pa., May 18, 1983.

4. Hussein, M. H., W. A. Woerner, M. Sharp, and C. Hwang. Pile Drive-ability and Bearing Capacity in High-Rebound Soils. Proc., ASCE GEO Congress, Atlanta, Ga., 2006.

5. Murrell, K. L., G. J. Canivan, and W. M. Camp III. High and Low Strain Testing of Bouncing Piles. Proc., 33rd Annual and 11th International Conference on Deep Foundations, New York, Oct. 15–17, 2008.

The opinions, findings, and conclusions expressed in this paper are those of the authors and not necessarily those of the Florida Department of Transportation.

The Foundations of Bridges and Other Structures Committee peer-reviewed this paper.

FIGURE 9 Predicted rebound using NSPT and fines content from Equation 1 versus actual PDA rebound.