FHWA NHI Manual: Drilled Shafts Construction Procedures and LRFD Design Methods
The FHWA has released for download a comprehensive update to the 1999 O’Neil and Reese manual “Drilled Shafts: Construction Procedures and Design Methods”, lovingly referred to in the industry as the “Brown Book” or the “Drilled Shaft Bible”. This 2010 manual from the National Highway Institute (NHI) of the FHWA is entitled “Drilled Shafts: Construction Procedures Procedures and LRFD Design Methods” and was authored by Dan A. Brown, Ph.D, P.E. of Dan Brown and Associates, John P. Turner, Ph.D, P.E. of the University of Wyoming, and Raymond J. Castelli, P.E. From an FHWA Memo on the manual:
Distributed with this memorandum is the publication entitled "Drilled Shafts: Construction Procedures and LRFD Design Methods" (FHWA-NHI-10-016). This manual is the reference text used for the National Highway Institute (NHI) course numbered 132014 on Drilled Shafts. The publication will become the tenth in the series of geotechnical engineering guidelines called "Geotechnical Engineering Circulars." Geotechnical Engineering Circular (GEC) No. 10 is prepared as a significant revision and update to "Drilled Shafts: Construction Procedures and Design Methods" (FHWA IF-99-025), and reflects the standard of practice for the design, construction and inspection of these features. The guidance is developed following Load and Resistance Factor Design (LRFD) procedures and will enable engineers to identify and evaluate technical feasibility and potential applications. The text is developed with a sufficiently broad scope to be of value to a wide range of transportation specialists responsible for assisting with selection, design, development of materials specifications, construction monitoring, and contracting methods for Drilled Shafts.
Download the “Drilled Shafts: Construction Procedures and LRFD Design Methods” manual from the FHWA’s NHI.
This manual has been used as the reference text for the NHI course 132014 since sometime in the beginning of the year, but to my knowledge, was just recently made available on the FHWA’s website. In addition to being the NHI manual, the document was also given a GEC designation, GEC No. 10, similarly to what was done with the recently updated “Design of Mechanically Stabilized Earth Retaining Walls and Reinforced Soil Slopes” manual, which was designated GEC No. 11 but became available to the public before this manual.
What’s New in the 2010 Drilled Shaft Manual
Digesting this massive manual is going to take some time…a lot of time, as it comes in at 970 pages, over 200 pages larger than the 1999 O’Neill and Reese version. But here are a few of my preliminary and general comments about what jumped out at me. This is anything but an exhaustive list.
- Beautiful color photos and diagrams of all aspects of drilled shaft construction, equipment and testing
- Updates on the latest state of the practice on the construction side of things
- GeoMaterials section (Chapter 3) seems much expanded, split out from the Site Characterization section
- Expanded section on casings and liners
- Much expanded section on drilling fluids in shaft construction (Chapter 7)
- Chapter 10 – LRFD for drilled shaft design, an easy to read interpretation of AASHTO LRFD guidelines and supplemental information
- Separate chapters for the design process (11), lateral loading (12), axial loading (13) and shaft groups (14).
- Extreme events like scour and earthquakes are addressed in Chapter 15
- Structural design of drilled shafts chapter (16)
- Seemingly much expanded section on field load testing
- Something I’m very interested in checking out, a new chapter (21) on remediation of deficient drilled shafts
- Appendix C commentary on axial loading includes discussion of bearing capacity theory for base resistance and equations for design of base resistance with post-grouting of the drilled shaft base
- Appendix D axial load-deformation response: no longer includes the O’Neill and Reese normalized load transfer curves that have been in AASHTO for computing settlement. They include the method proposed by Kulhawy.