Load and Resistance Factor Design (LRFD)

NCS GeoResources and LRFD

NCSG has been at the forefront of the implementation of Load and Resistance Factor Design (LRFD). We invite you to learn more details about our contributions to LRFD implementation and research by browsing through the many LRFD publications available for free Downloads and the various publications on this page. So bookmark this website and check for future postings of interesting LRFD-related articles.

The following are examples of LRFD-based projects performed by NCSG:

  1. Developing procedures to calibrate service limit state for foundations for AASHTO and FHWA as part of SHRP2 Solutions program. Download the manual titled “Incorporation of Foundation Movements in AASHTO LRFD Bridge Design Process – Second Edition.“
  2. Developing policy guidelines for the design of drilled shafts and spread footings for the Arizona Department of Transportation (ADOT).
  3. Developing policy guidelines for the collection and presentation of geotechnical data for evaluation of scour in the LRFD context for Pima County Department of Transportation (PCDOT).
  4. Teaching the geotechnical-related components of the 3-day, 4-day and 5-day versions of the course “LRFD for Highway Bridge Substructures and Retaining Walls” for the National Highway Institute (NHI) of the Federal Highway Administration (FHWA) under a subcontract to Ryan R. Berg and Associates.
  5. Contributing to the development of the LRFD aspects of the NHI’s course on Mechanically Stabilized Earth (MSE) Walls and Reinforced Soil Slopes. This manual was issued by FHWA as Geotechnical Engineering Circular (GEC) #11.
  6. Developing policy guidelines for the design of MSE walls for the Arizona Department of Transportation. This effort includes the development of comprehensive specifications and detailed example problems, which are also included in the 2009 NHI/FHWA manual on MSE walls.
  7. Developing comprehensive examples problems to illustrate the use of LRFD methodology for the design of standard cast-in-place retaining walls for the Arizona Department of Transportation (ADOT).
  8. Developing 20 LRFD based webinars on different geotechnical topics for the American Society of Civil Engineers (ASCE). Hundreds of participants have attended these webinars since their inception in 2010.
  9. As part of a team led by Modjeski and Masters (M&M), developing new design codes that incorporate a rational approach to the evaluation of the expected service life of highway bridges based on service limit state (SLS) for durability and performance of bridge systems, subsystems, components, and details that are critical to reaching the expected service life and assuring an actual service life beyond 100 years. Led by Dr. John M. Kulicki, PE, of M&M, the key team members include Dr. Wagdy G. Wassef, PE, of M&M, Dr. Dennis R. Mertz, PE, of University of Delaware, Dr. Andrzej S. Nowak, PE, of University of Nebraska and Dr. Naresh C. Samtani, PE, of NCSG. The results of this work are available from Transportation Research Board (TRB). The project was funded as part of the Strategic Highway Research Program (SHRP) of the TRB.
  10. Developing a comprehensive guidance manual for the the Resource Center Technology Deployment Program of the FHWA, titled Selection of Spread Footings on Soils to Support Highway Bridge Structures. Written by Drs. Naresh Samtani and Ed Nowatzki of NCSG and Dr. Dennis Mertz of the University of Delaware, this manual provides the geotechnical engineer and structural engineer with LRFD-based design aids and guidance for the use of spread footings for highway bridges on competent soils.
  11. Helping the New Mexico Department of Transportation (NMDOT) and the University of New Mexico (UNM) in calibration of resistance factors for drilled shafts in New Mexico soils.
  12. Contributing to the development and teaching of a practitioner-led, semester-long, senior/graduate level 3 CEU course, “Integrated Highway Bridge Design Using LRFD Methodology”, for the Department of Civil Engineering and Engineering Mechanics, University of Arizona, Tucson.
  13. Presentation at the 42nd Annual Southwest Geotechnical Conference in Phoenix, AZ, for introducing the upcoming changes in AASHTO LRFD related to calibration of service limit state. 
  14. Making numerous invited presentations on various LRFD topics.