TABLE OF CONTENTS Dennis R. Mertz, Ph.D., P.E.
Professor of Civil Engineering
University of Delaware
Newark, Delaware
This chapter provides guidance to highway bridge designers in the application of standard design specifications to the more common types of bridges. In addition, it provides rules of thumb to result in cost-effective and safe structures. Because of the complexity of modern bridge design and construction, this chapter does not provide comprehensive treatment of all types of bridges. Because specifications are continually being revised, readers are cautioned to use the latest edition of the applicable specification, including interims, in practical applications.
Traditionally, design of most highway bridges in the United States was in accord with the Standard Specifications for Highway Bridges (Standard Specifications) published by the American Association of State Highway and Transportation Officials (AASHTO), 444 N. Capitol St., NW, Washington, DC 20001. However, in the early 1990s, AASHTO introduced a new, more modern and comprehensive highway bridge design specification, the LRFD Bridge Design Specifications (LRFD Specifications) as an equal alternative to the Standard Specifications. AASHTO publishes new editions of these specifications periodically, and annual revisions to each are published as Interim Specifications.
The Federal Highway Administration (FHWA) and AASHTO established a goal to design all new highway bridges after October 2007 in accord with the LRFD Specifications. Since 1994, the states have been slowly moving toward full adoption of the LRFD Specifications. Interim changes to the Standard Specifications have not been made since 2000, and a final complete version as frozen in 2000...
