1

43rd ANNUAL FHWA MIDWEST GEOTECHNICAL CONFERENCEBloomington, MINNESOTA, OCTOBER 1-3, 2014

State of Practices in Databases for Deep Foundations Load Tests

Dr. Naser Abu-Hejleh, FHWA Resource Center

Dr. Murad Abu-Farsak, Louisiana State University

Dr. Muhannad T. Suleiman, Lehigh University

Dr. Ching Tsai, Louisiana DOT

.

2

Presentation Goals

Help State DOTs and their researchers/consultants to:

Use foundation load test databases

Benefit from existing foundation load test databases

Develop quality foundation load test databases

More accurate and economical foundations geotechnical design

3

Presentation Outline

1. Applications of foundation load test databases

2. Contents and use of:

FHWA Deep Foundation Load test Database

Other Deep Foundation Load Test Databases

3. Recommendations

4

Types of Methods to Determine Foundations Geotechnical Resistance & Displacement

1. Full-scale static load test: most accurate method

2. Simple prediction methods (analytical expression):

Static analysis (α- and β- methods)

Soil/rock design properties (e.g., Rn= 2.5Abqu)

Dynamic analysis (dynamic load test; formula)

Driving records and hammer/soil information

5

Load Test: Direct Measurements of

Foundations Resistance/Displacements

0

5

10

15

20

25

30

0 1 2 3

Top

Defl

ect

ion

(mm

)

Axial Load, Q (MN)

Qtotal = Qs + Qb

Pred. Qs

Pred. Qb

Meas. Total

Meas. Shaft

Meas. Base

Load test data can be used to develop more accurate/economical simple design methods

6

How Foundation Load Test Data Can Be Used?

1. In the individual projects they are used in to:

Optimize and/or verify the geotechnical design

2. Above and in the future to improve the simple

geotechnical design methods. Needs:

Quality and complete data

Document the data (databases)

Minimal extra efforts compared to the benefits!

7

Instrumented and proof Load test: Procedure, direction & results (load-settlement curve)

Test foundation: type, layout,

dimensions, construction, quality control

Soil/rock around the test foundation:

Design properties and the procedure

to obtain them.

Foundations Load Test Database = Quality and Complete Data at Load Test Sites

8

Analysis of Load Test Databases

For a group of test foundations, evaluate & compare:

Measured resistance/displacement from load test

Predicted resistance/displacement from the simple

design methods that will be evaluated.

Similar design and construction conditions for test and

production foundations

9

Applications of Foundation Load Test Databases

By Designers: perform more accurate and economical

design for production foundations in their projects

10

Applications of Foundation Load Test Databases

By Researchers: reliability calibration of various

(AASHTO, local, new) design methods:

Develop resistance factors

Identify/develop more accurate and economical:

Simple design methods

Testing methods to determine soil/rock properties

Methods for construction and quality control

11

This requires databases that include:

Quality and complete load test records

Statistically adequate to cover the common design

and construction conditions in the US

Local databases are needed:

Accounts for specific design/construction

conditions (more economical/accurate)

For methods not calibrated in AASHTO

Future: Reliability-Based Foundation Geotechnical Design Methods

12

FHWA Deep Foundation Load Test Database (DFLTD)

Most comprehensive and largest database 1307 load tests collected during 1985-2003

Load transfer results for 21 test foundations

Used to develop other databases (discussed later)

Limitations: Missing and limited information

Distribution: contact FHWA (Dr. Naser Abu-Hejleh)

13

FHWA DFLTD Information

State # of Load Tests

State # of Load Tests

State # of Load Tests

California 327 Louisiana 245 Florida 163Mississippi 98 Texas 37 New York 36

Arizona 35 Pennsylvania 24 Hawaii 23South Carolina 19 Nevada 18 Colorado 11Massachusetts 11 Washington 10 New

Mexico8

Boring Data Lab Data SPT CPT PMT

723 752 971 275 75

Cohesive Non-Cohesive Variable Rock s IGM

119 263 715 978

Location by States

Subsurface Investigation

14

FHWA DFLTD Information

Pile Types

Drilled Shafts

Pile: Square

Concrete

Pile: Round

Concrete

Pile: Steel H-

pile

Pile: Timber

Pile: Step Tapered

Open Pipe Pile

371 356 175 104 62 60 51Screw Pile (3), Micropile (4), Monotube (18), Auger cast (9), Composite (13), Franki (10)

Type of LoadsCompression Tension Lateral

1132 67 44Type of Load Tests

Standard Quick Osterberg Statnamic692 394 24 131

Other CriteriaCyclic To Failure CAPWAP

109 712 113

Load Test

15

FHWA DFLTD Information

Construction Methods for Drilled ShaftsDrilled

and Grouted

Dry Wet

with Bentonite

Wet with

Casing Left

Wet with Casing

Withdrawn

With Polymer Slurry

Wet Water only

Cast-in-

Place

N/A

17 128 5 73 22 24 36 25 41

Construction Methods for Driven PilesImpact Driven

Mandrel Driven Concrete Filled

Vibrated Screw Pile

Jacked Vibrated and Driven

N/A

601 42 27 2 4 1 8

16

Other Deep Foundation Databases

PD/LT2000 (NCHRP Report 507, 2004 )

AASHTO’s LRFD resistance factors ()

Washington dynamic formula

for drilled shafts (Ohio, 2012)

New Mexico (2012)

24 drilled shaft load tests in granular soils

Resistance factors () for side resistance methods

17

Deep Foundation Databases

PSU for Driven Piles (Oregon, 2010).

Identified quality data from DFLTD and applicable to

Oregon practices

= 0.5 for wave equation analysis at EOD/BOR

for different combinations of pile and soil types

California

Has a large number of load tests, archived in the web

On-going research study

18

Deep Foundation Databases

Florida DOT (FDOT):

Long history in development of databases

Deep Foundation Database

627 load tests in Access database

Online database (100 load tests)

Local load test data

FDOT for driven piles and drilled shafts

19

Deep Foundation Databases

International Database (Long, 2009)

Illinois:

Evaluation of various static/dynamic analysis methods

Identified/developed the best methods

Updated Illinois DOT design specifications

Wisconsin: Evaluation of 5 dynamic analysis methods

and identified the best method

20

Deep Foundation Databases

Pilot & DSHAFT Iowa online databases (2010-2011)

Local data

Driven piles (275) and drilled shafts (38)

for driven piles:

Larger than AASHTO

Smaller than with calibration by fitting to ASD

21

Deep Foundation Databases

Louisiana Load Tests (2008, 2012)

Driven piles (53) and drilled shafts (26)

Local load tests

larger than AASHTO

Calibrate design methods not used in AASHTO

22

Recommendations

1. Develop a national protocol to obtain and report

quality and complete new data at load test sites:

Consistent procedure to obtain data: Follow AASHTO/FHWA procedures Consider local and new/better procedures

Report consistent data using similar: “Foundation Load Test Record Form” Guide: describe the data and the procedure to obtain

them

23

Recommendations

2. Identify and compile existing quality load test

data that were not documented

3. Deploy quality format and facilitate distribution

Consistent format with the national protocol

Flexibility to update, expand, modify, and access

Appealing user friendly interface to filter, sort, query,

and generate the needed information.

Long-term management and maintenance

Online databases

24

Recommendations

4. Develop quality and complete:

Local databases by states Using their data and data of others appropriate to

their design/construction conditions

Regional databases Of states with similar design/construction conditions

National databases: Bank for other states!!

\

25

Recommendations- Implementation

Collaboration between Public and Private

Highway Engineering Agencies

26

Questions?

Will e-mail you:

FHWA Deep Foundation Load Test Database (DFLTD)

2010 NHI Manual: “Implementation of LRFD

Geotechnical Design for Bridge Foundations”

Relevant Papers

2013 FHWA Report: “Implementation of AASHTO LRFD

Design Specification for Driven Piles.” 

Dr. Naser Abu-Hejleh, P.E.FHWA Resource Center

naser.abu-hejleh@dot.gov; (708) 283-3550