LRFD RESISTANCE FACTORS FOR MARYLAND RETAINING WALLS

American Association of State Highway and Transportation Officials (AASHTO), Load and Resistance Factor Design (LRFD) specifications for retaining walls were summarized and presented in this report. To carry out comparative design between allowable stress design (ASD) and LRFD specifications, three types of retaining walls that are used by the Maryland State Highway Administration were analyzed by both the ASD and LRFD methods of design. This provides a guide for engineers who are not familiar with LRFD methodology but are interested in implementing it. A spreadsheet program for the design of three types of retaining walls based on AASHTO LRFD specifications ere developed, which will facilitate the design of these walls for different geometry and soil properties. All analyses undertaken dealt only with the external stability of the wall, i.e., its resistance to overturning, sliding and bearing failure. Standard cantilever walls with different heights were then analyzed and their resistance factors determined. The resistance factors determined were found to be much less than the values recommended by the AASHTO specification, i.e., the walls were originally overdesigned. By varying the base dimension of a 20 ft high wall, a reduction in cross-sectional area of the wall of up to 34% can be achieved with the wall still within the AASHTO specification. Thus, unless there is a structural reason for the current dimensions of these cantilever walls, they can be reduced in cross-sectional area based on the geotechnical analyses undertaken, which will translate into a reduction in cost of the retaining wall. A study was also undertaken on the effect of the life load surcharge on the resistance factors. It was found that with the larger life load surcharge recommended by the AASHTO specification for shorter walls compared to the taller walls, the resistance factors are still acceptable. However, the shorter walls have higher resistance factors, as was expected.

• Record URL:
  https://rosap.ntl.bts.gov/view/dot/38792
• Corporate Authors:

  University of Maryland, College Park

  Department of Civil and Environmental Engineering
  College Park, MD  United States  20742

  Maryland Department of Transportation

  State Highway Administration, 707 N Calvert Street
  Baltimore, MD  United States  21202
• Authors:
  • Aggour, M S
• Publication Date: 2004-4

Language

• English

Media Info

• Media Type: Digital/other
• Features: Appendices; Figures; References; Tables;
• Pagination: 115 p.

Subject/Index Terms

• TRT Terms: Design; Load and resistance factor design; Retaining walls; Specifications; Spreadsheets
• Uncontrolled Terms: Allowable stress design; Cantilever walls; Life load surcharge
• Subject Areas: Bridges and other structures; Design; Highways; I24: Design of Bridges and Retaining Walls;

Filing Info

• Accession Number: 00974297
• Record Type: Publication
• Report/Paper Numbers: MD-04-SP308B4D,, Final Report
• Files: NTL, TRIS, STATEDOT
• Created Date: May 28 2004 12:00AM