Optimal Sizing of Prestressed Bridge Superstructures in Pennsylvania by LRFD

摘要

style="text-align: left;">Recent implementation of the LRFD (Load and Resistance Factor Design) and metric specifications for bridges in Pennsylvania resulted in significant design changes. To shorten the design path, the  authors contributed to the development of a computer-based preliminary design software (QUIKBEAM99) that generates several potential solutions for a given bridge span and bridge width. These   solutions are selected from PennDOTa€?s extensive inventory of geometric shapes. The program yields the section sizes, volume of precast concrete, the required release strength and the number of strands. These parameters allow the rapid selection of an optimum solution for a given case. The paper details the various steps used in the procedure development, which was sponsored by the Prestressed Concrete Association of Pennsylvania. Based on statistical analyses, it is found that the adopted approach (multiple linear regression) predicts the major parameters of concrete strength and number of strands within a small relative error. >References style="text-align: left;">1. AASHTO Standard Specifications for Highway Bridges, 16th Edition, American Association of State Highway and Transportation Officials, Washington, DC, 1996. style="text-align: left;">2. AASHTO-LRFD Design Specifications, SI Units, First Edition, American Association of State Highway and Transportation Officials, Washington, DC, 1994 and 1998. style="text-align: left;">3. Design Manual, Part 4 (Metric), Publication No. 15 M, Pennsylvania Department of Transportation, Harrisburg, PA,1996. style="text-align: left;">4. Standard Drawings for Bridge Design, BDM-600 Series, Publication 21 8M, Pennsylvania Department of Transportation, Harrisburg, PA, 1997. style="text-align: left;">5. QUIKBEAM Version 4.0 and Usera€?s Manual, Prestressed Concrete Association of Pennsylvania, Allentown, PA, 1992 to 1995. style="text-align: left;">6. QUIKBEAM99 Version 1.50 and Usera€?s Manual, Prestressed Concrete Association of Pennsylvania, Allentown, PA, 1999. style="text-align: left;">7. Aswad, G., and Aswad, A., target="_blank" title="a€?Rational Prediction of Bridge Girder Reinforcing and Strength,a€?" href="http://dx.doi.org/10.15554/pcij.05011991.68.77 ">a€?Rational Prediction of Bridge Girder Reinforcing and Strength,a€? PCI JOURNAL, V. 36, No.3, May-June 1991, pp. 68-75. style="text-align: left;">8. PSLRFD Software, Version 1.3, LRFD  Prestressed Concrete Girder Design and Rating, Pennsylvania Department of Transportation, Harrisburg, PA, 1998. style="text-align: left;">9. SAS/STAT Version 8, Usera€?s Guide, Volumes 1, 2 and 3, SAS Institute Inc., Cary, NC, 2000. style="text-align: left;">10. SAS/ETS Version 8, Usera€?s Guide, Volumes 1 and 2, SAS Institute Inc., Cary, NC, 2000.