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INTRODUCTION

The compilation of these specifications began in 1921 with the organization of the Committee on Bridges and Structures of the American Association of State Highway Officials. During the period from 1921, until printed in 1931, the specifications were gradually developed, and as the several divisions were approved from time to time, they were made available in mimeographed form for use of the State Highway Departments and other organizations. A complete specification was available in 1926 and it was revised in 1928. Though not in printed form, the specifications were valuable to the bridge engineering profession during the period of development.

The first edition of the Standard Specifications was published in 1931, and it was followed by the 1935, 1941, 1944, 1949, 1953, 1957, 1961,1965, 1969, 1973, 1977, 1983, 1989, 1992, and 1996 revised editions. The present seventeenth edition constitutes a revision of the 1996 specifications, including those changes adopted since the publication of the sixteenth edition and those through 2002.

In the past, Interim Specifications were usually published in the middle of the calendar year, and a revised edition of this book was generally published every 4 years. However, since the Federal Highway Administration and the States have established a goal that the LRFD standards be used on all new bridge designs after 2007, only edits related to technical errors in the seventeenth edition will be made hereafter. These Standard Specifications are applicable to new structure designs prior to 2007 and for the maintenance and rehabilitation of existing structures. Future revisions will have the same status as standards of the American Association of State Highway and Transportation Officials (AASHTO) and are approved by at least two-thirds of the Subcommittee on Bridges and Structures. These revisions are voted on by the Association Member Departments prior to the publication of a new edition of this book, and if approved by at least two-thirds of the members, they are included in a new edition as standards of the Association. Members of the Association are the 50 State Highway or Transportation Departments, the District of Columbia, and Puerto Rico. Each member has one vote. The U.S. Department of Transportation is a nonvoting member.

Future revisions will be displayed on AASHTO's website via a link from the title's book code listing, HB-17, in the Bookstore of www.transportation.org. An e-mail notification will also be sent to previous purchasers notifying them that a revision is available for download. Please check the site periodically to ensure that you have the most up-to-date and accurate information.

The Standard Specifications for Highway Bridges are intended to serve as a standard or guide for the preparation of State specifications and for reference by bridge engineers.

Primarily, the specifications set forth minimum requirements which are consistent with current practice, and certain modifications may be necessary to suit local conditions. They apply to ordinary highway bridges and supplemental specifications may be required for unusual types and for bridges with spans longer than 500 feet.

Specifications of the American Society for Testing and Materials (ASTM), the American Welding Society, the American Wood Preservers Association, and the National Forest Products Association are referred to, or are recognized. Numerous research bulletins are noted for references.

The American Association of State Highway and Transportation Officials wishes to express its sincere appreciation to the above organizations, as well as to those universities and representatives of industry whose research efforts and consultations have been most helpful in continual improvement of these specifications.

Extensive references have been made to the Standard Specifications for Transportation Materials and Methods of Sampling and Testing also published by AASHTO, including equivalent ASTM specifications which have been reproduced in the Association's Standard Specifications by permission of the American Society for Testing and Materials.