Optimal Sizing of Prestressed Bridge Superstructures in Pennsylvania by LRFD

摘要

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 PennDOT’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.