Assessment of Several Nominal Resistance Interpretation Criteria for Drilled Foundations

Antonio Kodsy, Magued Iskander, Nikolaos Machairas

Research output: Contribution to journalArticlepeer-review


Agreeing on the nominal resistance (aka. capacity) derived from any load-settlement curve requires the use of an interpretation criterion. Few of the currently available criteria have been originally designed for drilled foundations despite the increasing use of such piles for supporting infrastructure projects. The performance of 16 interpretation criteria used in current geotechnical practice was assessed using a database of 194 load tests conducted on drilled shafts. Their performance was evaluated in terms of: (1) applicability; (2) correlation among each other; and (3) the effect of drilled shaft diameter, length, and soil type. Eight of the 16 methods could not be reliably used. Capacities interpreted from the remaining eight were consistent but resulted in excessive settlement in a few cases. Performance was also evaluated in terms of serviceability. A new criterion is proposed, where the nominal resistance is defined as the load corresponding to the smallest of (1) a settlement equal to the elastic compression of a free-standing column plus 0.75 in. (20 mm); (2) the load at plunging or strain-softening; or (3) settlement corresponding to 5% of the pile diameter, unless modified by the structural engineer of record. The proposed method showed good correlation with several established criteria while including a built-in serviceability safeguard against excessive settlement.

Original languageEnglish (US)
Article number04021181
JournalJournal of Geotechnical and Geoenvironmental Engineering
Issue number2
StatePublished - Feb 1 2022


  • Bored piles
  • Caisson
  • Capacity
  • Drilled shaft
  • Failure
  • Interpretation criteria
  • Interpreted load
  • NYU criterion
  • Pier

ASJC Scopus subject areas

  • General Environmental Science
  • Geotechnical Engineering and Engineering Geology


Dive into the research topics of 'Assessment of Several Nominal Resistance Interpretation Criteria for Drilled Foundations'. Together they form a unique fingerprint.

Cite this