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Advances in Civil Engineering
Volume 2012 (2012), Article ID 673821, 8 pages
http://dx.doi.org/10.1155/2012/673821
Research Article

Optimization of Post-Tensioned Box Girder Bridges with Special Reference to Use of High-Strength Concrete Using AASHTO LRFD Method

1Department of Engineering and Computer Science, West Texas A&M University, WTAMU Box 60767, Canyon, TX 79016, USA
2Engineering Technical Group, Arizona Department of Transportation, 205 South 17th Avenue, MD 618E, Phoenix, AZ 85007, USA
3Design Section, Nfra Inc., 77 E. Thomas Road, Suite 200, Phoenix, AZ 85012, USA

Received 9 January 2012; Revised 17 May 2012; Accepted 24 May 2012

Academic Editor: Sami W. Tabsh

Copyright © 2012 Byungik Chang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

With the Federal Highway Administration-mandated implementation of the LRFD specifications, many state departments of transportation (DOTs) have already started implementing LRFD specifications as developed by the AASHTO. Many aspects of the LRFD specifications are being investigated by DOTs and researchers in order for seamless implementation for design and analysis purposes. This paper presents the investigation on several design aspects of post-tensioned box girder bridges designed by LRFD Specifications using conventional or High-Strength Concrete (HSC). A computer spreadsheet application was specifically developed for this investigation. It is capable of analysis, design, and cost evaluation of the superstructure for a cast-in-place post-tensioned box girder bridge. Optimal design of a post-tensioned box girder is achievable by correct selection of design variables. Cost evaluation of superstructures with different geometrical and material configurations has led to the development of optimum design charts for these types of superstructures. Variables used to develop these charts include, among others, span length, section depth, web spacing, tendon profile, and concrete strength. It was observed that HSC enables the achievement of significantly longer span lengths and/or longer web spacing that is not achievable when using normal strength concrete.