Transcript Naser Abu-Hejleh "Loadtest Database" FHWA

43rd ANNUAL FHWA MIDWEST GEOTECHNICAL CONFERENCE
Bloomington, 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
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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
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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
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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
4
Load Test: Direct Measurements of
Foundations Resistance/Displacements
Axial Load, Q (MN)
0
1
2
0
Top Deflection (mm)
5
10
15
Qtotal = Qs + Qb
Pred. Qs
20
Pred. Qb
Meas. Total
25
Meas. Shaft
Meas. Base
30
Load test data can be used to develop more
accurate/economical simple design methods
5
3
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!
6
Foundations Load Test Database =
Quality and Complete Data at Load Test Sites
 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.
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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
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Applications of Foundation Load Test Databases
By Designers: perform more accurate and economical
design for production foundations in their projects
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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
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Future: Reliability-Based
Foundation Geotechnical Design Methods
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
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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)
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FHWA DFLTD Information
Location by States
State
# of
Load Tests
State
California
Mississippi
Arizona
South Carolina
Massachusetts
327
98
35
19
11
Louisiana
Texas
Pennsylvania
Nevada
Washington
# of
Load
Tests
245
37
24
18
10
State
# of
Load Tests
Florida
New York
Hawaii
Colorado
New
Mexico
163
36
23
11
8
Subsurface Investigation
Boring Data
Lab Data
SPT
CPT
PMT
723
752
971
275
75
Cohesive
Non-Cohesive
Variable
119
263
715
13
Rock s
IGM
978
FHWA DFLTD Information
Pile Types
Drilled
Shafts
Pile:
Pile:
Pile:
Pile:
Pile: Step
Open
Square
Round
Steel H- Timber
Tapered
Pipe
Concrete
Concrete
pile
Pile
371
356
175
104
62
60
51
Screw Pile (3), Micropile (4), Monotube (18), Auger cast (9), Composite (13),
Franki (10)
Load Test
Compression
1132
Standard
692
Cyclic
109
Type of Loads
Tension
Lateral
67
44
Type of Load Tests
Quick
Osterberg
Statnamic
394
24
131
Other Criteria
To Failure
CAPWAP
712
113
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FHWA DFLTD Information
Construction Methods for Drilled Shafts
Drilled Dry
Wet
Wet
and
with
with
Grouted
Bentonite Casing
Left
17
128
5
Wet with
With
Casing
Polymer
Withdrawn Slurry
73
22
24
Wet
Water
only
36
Cast- N/A
inPlace
25
41
Construction Methods for Driven Piles
Impact
Driven
Mandrel Driven
Concrete Filled
Vibrated
Screw
Pile
Jacked
Vibrated and
Driven
N/A
601
42
27
2
4
1
8
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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
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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
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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
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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
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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
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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
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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
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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
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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!!
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Recommendations- Implementation
Collaboration between Public and Private
Highway Engineering Agencies
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Questions?
Dr. Naser Abu-Hejleh, P.E.
FHWA Resource Center
[email protected]; (708) 283-3550
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.”
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