Chicago — The National Steel Bridge Alliance’s (NSBA) Continuous Span Standards for Steel Plate Girder Bridges are now available for free download. Developed to assist engineers and contractors during the type, size and location (TS&L) phase of projects, the standards offer conceptual solutions for three-span bridges with center spans between 150 feet and 300 feet and balanced end spans at 78 percent of the main span length.
"The Continuous Span Standards for Steel Plate Girder Bridges are designed to help mitigate the inherent risk in using preliminary designs for schedule, initial cost and cost growth estimates," said Bill McEleney, NSBA managing director.
All information is presented in easy-to-understand tables. Tabulated information includes: flange and web plate sizes, diaphragm spacing, intermediate stiffener locations, shear stud spacing, camber tables, girder weights and total weights. Girder spacing ranges from 7.5 feet to 12 feet with homogeneous and hybrid plate solutions available.
"If you can't find a standard that matches your project's geometry, we've included the NSBA LRFD Simon input files that were used to build the standards," added McEleney. "Just find the corresponding file, open it in the free LRFD Simon software, change the geometry and/or loading requirements and run the software. LRFD Simon provides a complete output of the required information."
The standards simplify the process for selecting a girder size and can be used to propose preliminary design on bid day, yet are accurate enough to keep cost growth in check once the project has been won and final designs are prepared.
For more information and to download a free copy of the standards, visit www.steelbridges.org/spanstandards.