This report presents proposed AASHTO LRFD specifications for structural supports for highway signs, luminaires, and traffic signals. The proposed specifications are arranged in three divisions: (1) design according to LRFD methodology; (2) construction, including material specifications, fabrication, and installation; and (3) asset management, including inventory, inspection, and maintenance. In June 2000, AASHTO and the Federal Highway Administration agreed on an implementation plan for the design of highway structures utilizing the load and resistance factor design (LRFD) methodology. As part of that agreement, all new culverts, retaining walls, and other standard structures on which states initiate preliminary engineering after October 1, 2010, shall be designed according to the LRFD specifications. The current edition of the AASHTO Standard Specifications for Structural Supports for Highway Signs, Luminaires, and Traffic Signals is generally based on the working stress design method. Also, the design, construction, and inspection languages are intertwined in the specifications and commentary, resulting in a document that is cumbersome and difficult to follow. The probability-based specification (i.e., LRFD) will result in structures that are based on a more uniform set of design criteria. The specifications will promote quality construction and fabrication practices and will address the current shortcomings of inspection and maintenance of these ancillary structures. The combination of these efforts will allow agencies to better design, manage, and maintain these transportation assets to improve the safety and reliability of structural supports nationwide. Agencies will be in a better position to meet the LRFD implementation plan, and the provisions will facilitate the design, construction, inspection, and maintenance of structural supports for highway signs, luminaires, and traffic signals. Research was performed under NCHRP Project 10-80 by BridgeTech, Inc. The objective of this research was to develop proposed AASHTO LRFD specifications for structural supports for highway signs, luminaires, and traffic signals. Additionally, 16 comprehensive design examples were developed to illustrate the application of the new specifications. The report includes the Research Report, which documents the entire research effort, and the Calibration Report (i.e., Appendix A). Appendix B: AASHTO LRFD Specifications will be published by AASHTO. Other appendices are not published but are available on the TRB website. These appendices are titled as follows: • Appendix C: Design Examples, • Appendix D: Survey Results, and • Appendix E: Fatigue Resistance Comparisons. (Author/publisher)
Samenvatting