Recommended Design Specifications for Live Load Distribution to Buried Structures

The design and evaluation of buried structures requires an understanding of how vertical earth loads and vehicular live loads are transmitted through earth fills. Force effects due to vehicular live loads are determined by approximate methods. The approximate method for estimating the distribution of vehicular live loads through earth fill in the AASHTO Standard Specifications has, over many years, produced designs that have performed acceptably. The AASHTO LRFD Bridge Design Specifications use a different approximate method that significantly increases live load pressures on buried structures compared with the Standard Specifications. When combined with the increased dynamic load allowance prescribed in the LRFD Specifications, this increase is even greater. In addition, the basis of the approximate methods in both codes is not well documented or understood. Therefore, a more rational approach that takes into account the numerous factors that affect the actual live load distribution on these structures is needed. The approach should be validated by comparison with buried structure performance. The objective of this project is to develop recommended revisions to the AASHTO LRFD Bridge Design Specifications relating to the distribution of live load to buried structures. In addition, refined methods of analysis for the distribution of live load to buried structures shall be developed.

• Record URL:
  http://www.trb.org/TRBNet/ProjectDisplay.asp?ProjectID=409

Language

• English

Project

• Status: Completed
• Funding: $350000.00
• Contract Numbers:

  Project 15-29

• Sponsor Organizations:

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590

  American Association of State Highway and Transportation Officials (AASHTO)

  444 North Capitol Street, NW
  Washington, DC  United States  20001

  National Cooperative Highway Research Program

  Transportation Research Board
  500 Fifth Street, NW
  Washington, DC  United States  20001
• Project Managers:

  Dekelbab, Waseem

• Performing Organizations:

  CNA Consulting Engineers

  ,    
• Principal Investigators:

  Nelson, Charles

• Start Date: 20050421
• Expected Completion Date: 0
• Actual Completion Date: 20090427
• Source Data: RiP Project 10641

Subject/Index Terms

• TRT Terms: Bridge design; Design; Evaluation and assessment; Fills; Force; Live loads; Structures
• Identifier Terms: National Cooperative Highway Research Program
• Subject Areas: Bridges and other structures; Design; Highways; Planning and Forecasting; I30: Materials;

Filing Info

• Accession Number: 01463069
• Record Type: Research project
• Source Agency: National Cooperative Highway Research Program
• Contract Numbers: Project 15-29
• Files: RiP, USDOT
• Created Date: Jan 3 2013 2:16PM