• DFI Europe
  • DFI Trust

Drilled Shaft

Advancing the state of the practice or state of the art in design, construction, and quality verification of drilled shaft foundation systems.

Committee Chair

Paul Axtell, P.E., D.GE
Dan Brown and Associates PC

Axtell is the Chief Operating Officer and a Senior Principal Engineer for Dan Brown and Associates in Overland Park, Kansas.  In recent years, Paul has primarily focused on foundations for major bridge projects across the nation, delivered under a variety of project delivery methods.  He is the Geotechnical Engineer of Record for eight Mississippi River Crossings and has acted as foundation design, construction, or load test consultant on several others.

Axtell holds a B.S. degree in civil engineering from the University of Missouri and a M.S. degree in engineering from the University of Texas with a geotechnical emphasis.  He is registered as a professional engineer in 7 states and is a diplomate of the ASCE Academy of Geo-Professionals.  Paul has over 20 years of experience in geotechnical and foundation engineering and has authored or co-authored more than 25 technical papers.  Since 2013, he has served as chairman of the Deep Foundations Institute Drilled Shaft Committee.  Axtell serves on the Board of Directors for the ASCE Academy of Geo-Professionals and was recently honored with admittance into the University of Missouri’s Civil Engineering Academy of Distinguished Alumni.


Tremie concrete pour simulation for 52 ft deep drilled shaft.
Colors represents the age of concrete. Stages simulate the lifted tremie pipe.
The oldest concrete is pushed to the top of shaft.

Guide to Tremie Concrete for Deep Foundations (2nd Edition)

EFFC-DFI task force developed guidance for characterization related to performance, mix design process, and methods used to test fresh concrete.

Guide to Support Fluids for Deep Foundations (1st Edition)

EFFC-DFI task force outlined the state of the art of support fluid practice to improve existing design, testing and practices for deep foundation elements – bored piles (drilled shafts), barrettes (LBEs) and diaphragm wall panels.

CSL Task Force

Supporting Testing and Evaluation Committee review of existing cross hole sonic logging rating criteria and proposing improvements for potential future incorporation in codes and specifications.

Side and Base Resistance Task Force

Studying the mechanisms of load transfer between side and base resistance in drilled shafts. Click below for consensus document on rock-socketed drilled shafts. Research on soil-supported drilled shafts continues.


FHWA Geotechnical Engineering Circular No. 10 (FHWA-NHI-18-024) Drilled Shafts: Construction Procedures and LRFD Design Methods

FHWA Evaluation and Guidance Development for Post-Grouted Drilled Shafts for Highways

Final Report: Workshop on Quality Assurance for Post-Grouted Drilled Shafts

Manual for Non Destructive Testing and Evaluation of Drilled Shafts (#TM-NDT-1)

Drilled Shaft Inspector’s Manual (2nd edition) (#TM-DS-1)