text-only page produced automatically by Usablenet Assistive Skip all navigation and go to page content Skip top navigation and go to directorate navigation Skip top navigation and go to page navigation
National Science Foundation
Awards
design element
Search Awards
Recent Awards
Presidential and Honorary Awards
About Awards
Grant Policy Manual
Grant General Conditions
Cooperative Agreement Conditions
Special Conditions
Federal Demonstration Partnership
Policy Office Website



Award Abstract #0936627

NEESR Payload: Characterization of Dynamic Soil-Pile Interaction by Random Vibration Methods

NSF Org: CMMI
Div Of Civil, Mechanical, & Manufact Inn
divider line
Initial Amendment Date: July 17, 2009
divider line
Latest Amendment Date: July 17, 2009
divider line
Award Number: 0936627
divider line
Award Instrument: Standard Grant
divider line
Program Manager: Richard J. Fragaszy
CMMI Div Of Civil, Mechanical, & Manufact Inn
ENG Directorate For Engineering
divider line
Start Date: August 15, 2009
divider line
End Date: July 31, 2012 (Estimated)
divider line
Awarded Amount to Date: $99,913.00
divider line
ARRA Amount: $99,913.00
divider line
Investigator(s): Jeramy Ashlock jashlock@iastate.edu (Principal Investigator)
divider line
Sponsor: Iowa State University
1138 Pearson
AMES, IA 50011-2207 (515)294-5225
divider line
NSF Program(s): NEES RESEARCH
divider line
Program Reference Code(s): 038E, 041E, 043E, 1057, 1576, 6890, CVIS
divider line
Program Element Code(s): 7396

ABSTRACT

This award is funded under the American Recovery and Reinvestment Act of 2009

(Public Law 111-5).

This award is an outcome of the NSF 09-524 program solicitation ''George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES) Research (NEESR)'' competition. This Payload project will be led by Iowa State University (ISU) and will utilize NEES equipment from the University of California, Los Angeles and the experimental field-test setup from the NEESR-SG project entitled "Understanding and Improving the Seismic Behavior of Pile Foundations in Soft Clays" (Award #0830328). The overall goal of the project is to contribute to improved experimental and computational tools to bridge the gap between theory and observation for soil-foundation systems under realistic multi-directional loading. Despite many years of significant advances in theoretical and experimental research, significant discrepancies remain between experimental measurements and theoretical predictions of general three-dimensional dynamic pile-soil interaction. These discrepancies may be partially attributed to a host of contributing factors such as complicated soil-pile contact conditions, difficulties in performing full-scale dynamic tests, and the statistical variation of the engineering properties of soils coupled with the challenge of their in-situ measurement. Such shortcomings in current prediction capabilities can lead to unsafe under-design or costly over-design.

The focus of this Payload project is to expand the existing NEES technologies and testing capabilities for characterizing dynamic soil-pile interaction, and to improve the accuracy of current analytical and computational simulation tools. Field vibration tests will be performed on piles installed in improved and unimproved soft clays to gain a fundamental understanding of the seismic response of piles in these soil conditions. Specific goals of the project are to; (1) evaluate the effectiveness of using a servo-hydraulic inertial mass shaker and broadband random excitation for characterizing the dynamic behavior of piles in improved and unimproved clays, (2) improve the efficiency of current testing techniques by combining the traditionally separate vertical and horizontal harmonic excitation cases into a single multi-modal random-vibration test with synchronous vertical and coupled horizontal-rocking motions, (3) investigate the use of an experimental technique involving chaotic impulse loading which has shown great success in scaled-model centrifuge tests, (4) compare the relative effectiveness of using sinusoidal, random and chaotic impulse excitation types for characterizing the elastodynamic response of the soil, (5) evaluate the predictive capabilities of current analytical and computational techniques against the measured responses of piles in improved and unimproved clays and develop corrections if necessary, and (6) investigate whether experimental behavior observed in recent centrifuge studies of piles in sands extends to piles in clays.

This project will generate a number of practical experimental methods and a substantive database towards a more complete understanding of the fundamental behavior of dynamic soil-pile interaction. Specific tools to be developed include an innovative method for dynamic in-situ characterization of soil-pile interaction using non-destructive random vibration techniques, improved computational simulation tools to incorporate effects of pile installation and stress-dependence on the soil's shear modulus and damping, and modifications to current engineering theories which can be immediately applied in practice. In the long term, lessons learned in this project will be extended to understanding the dynamic behavior of a greater range of soil conditions as well as pile groups. The experimental and computational simulation techniques generated by this research will improve our understanding of fundamental soil-foundation-structure interaction, enabling more accurate models for foundation design and leading to improvements in earthquake hazard mitigation.

This project will involve the NEES community through teleparticipation, and a web site will be created with sections tailored for disseminating the research results to K-12 students, the general public, and the earthquake engineering community. Preliminary dynamic field-tests of a pile will be incorporated into a graduate course in soil dynamics at ISU, where students will have the option of analyzing the data for credit in a term project. Data from this project will be archived and made available to the public through the NEES data repository.

BOOKS/ONE TIME PROCEEDING

Ashlock, Jeramy C. and Fotouhi, Mohammad, K.. "Characterization of Dynamic Soil-Pile Interaction by Random Vibration Methods: Experimental Design and Preliminary Results", 08/01/2010-07/31/2011, "Proceedings of 2011 NSF Engineering Research and Innovation Conference, Atlanta, Georgia",  2011, "Proceedings of the 2011 NSF Engineering Research and Innovation Conference, Atlanta, Georgia, 11 pages, January 2011.".

Ashlock, Jeramy C. and Fotouhi, Mohammad K.. "Physical Poster at conference and Virtual Poster on NEES website: Characterization of Dynamic Soil-Pile Interaction by Random Vibration Methods: Experimental Design and Preliminary Results", 08/01/2010-07/31/2011, "Proceedings of 2011 NSF Engineering Research and Innovation Conference, Atlanta, Georgia",  2011, "http://nees.org/resources/2183".

Ashlock, J.C. and Fotouhi, M.K.. "Characterization of Dynamic Soil-Pile Interaction by Random Vibration Methods: Experimental Design and Preliminary Results", 08/01/2011-07/31/2012, "Proceedings of 2011 NSF Engineering Research and Innovation Conference, Atlanta, Georgia",  2011, "Proceedings of the 2011 NSF Engineering Research and Innovation Conference, Atlanta, Georgia, 11 pages, January 2011.".

Ashlock, Jeramy C. and Fotouhi, Mohammad K.. "Physical Poster at conference and Virtual Poster on NEES website: Characterization of Dynamic Soil-Pile Interaction by Random Vibration Methods: Experimental Design and Preliminary Results", 08/01/2011-07/31/2012, "Proceedings of 2011 NSF Engineering Research and Innovation Conference, Atlanta, Georgia",  2011, "http://nees.org/resources/2183".

Fotouhi, M.K., and Ashlock, J.C.. "Analysis of Experimental Dynamic Soil-Pile Interaction
by Approximate Numerical Solutions", 08/01/2011-07/31/2012, "Proceedings, 15th World Conference on Earthquake Engineering, Lisbon, Portugal",  2012, "Proc. 15th World Conference on Earthquake Engineering, Lisbon, Portugal, 10 pp., 2012.".

Ashlock, J.C. and Fotouhi, M.K.. "Physical poster presentation using e-poster: Analysis of Experimental Dynamic Soil-Pile Interaction by Approximate Numerical Solutions
", 08/01/2011-07/31/2012, "Proceedings, 15th World Conference on Earthquake Engineering, Lisbon, Portugal",  2012, "Proceedings, 15th World Conference on Earthquake Engineering, Lisbon, Portugal, 2012".

Ashlock, J.C. and Fotouhi, M.K.. "Analysis of Full-Scale Random Vibration Pile Tests in Soft Clay", 08/01/2011-07/31/2012, "Proc. 18th International Conference on Soil Mechanics and Geotechnical Engineering, Paris",  2013, "Proc. 18th International Conference on Soil Mechanics and Geotechnical Engineering, Paris, 4 pp., 2013
".

Ashlock, J.C. and Fotouhi, M.K.. "Physical poster presentation: Characterization of Dynamic Soil-Pile Interaction by Random Vibration
", 08/01/2011-07/31/2012, "2012 NSF Engineering Research and Innovation Conference, Boston, Massachusetts",  2012, "Proc. 2012 NSF Engineering Research and Innovation Conference, Boston, Massachusetts".

 

Please report errors in award information by writing to: awardsearch@nsf.gov.

 

 

Print this page
Back to Top of page
  FUNDING   AWARDS   DISCOVERIES   NEWS   PUBLICATIONS   STATISTICS   ABOUT NSF   FASTLANE  
Research.gov  |  USA.gov  |  National Science Board  |  Recovery Act  |  Budget and Performance  |  Annual Financial Report
Web Policies and Important Links  |  Privacy  |  FOIA  |  NO FEAR Act  |  Inspector General  |  Webmaster Contact  |  Site Map
National Science Foundation Logo
The National Science Foundation, 4201 Wilson Boulevard, Arlington, Virginia 22230, USA
Tel: (703) 292-5111, FIRS: (800) 877-8339 | TDD: (800) 281-8749
  Text Only Version