Evaluation of bridge foundations by impulse response methods

Richard J Finno*, Sarah L. Gassman

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review


This paper summarizes the results of a series of impulse response tests on inaccessible drilled shafts constructed at the National Geotechnical Experimentation Site (NGES) at Northwestern University. The drilled shafts are 610 to 910 mm in diameter and 12 to 27 m long, and are covered by pile caps up to 1.5 m thick. Results of tests on drilled shafts obscured by the pile caps have shown that useful information can be obtained below a "cutoff frequency" which is defined by the propagation velocity and the geometries of the intervening structure and the deep foundation. An extension of the conventional impulse response method using multiple geophones is described which makes interpretation of responses from the foundation easier by minimizing the effects of surface waves on the processed signals. Superposing the velocity responses from each geophone allows the reflections from the deep foundation to be more easily identified.

Original languageEnglish (US)
Pages (from-to)32-43
Number of pages12
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - Dec 1 1998
EventStructural Materials Technology III - San Antonio, TX, United States
Duration: Mar 31 1998Apr 3 1998


  • Bridge pier
  • Drilled shafts
  • Impulse response method
  • Multiple geophones

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


Dive into the research topics of 'Evaluation of bridge foundations by impulse response methods'. Together they form a unique fingerprint.

Cite this