DESIGN AND CONSTRUCTION OF THE NEW PORTAGEVILLE RAILROAD BRIDGE

摘要

The new bridge consists of a 483-ft 2-hinged spandrel-braced arch flanked on each side by three 80-ft approach spans for a total length of 963-ft. Modjeski and Master's solutions to challenges such as designing a structure type not covered by AREMA, designing for locked in thermal stresses, wind loading on double stacked rail cars, stresses from support settlement, all while working within the site and civil constraints of the scenic Genesee River Gorge will be presented. The spandrel-braced arch and the gorge topography determined that the cantilevered erection method was the optimal method of construction. This minimized the need for temporary works and eliminated the need for a physical footprint in the Genesee River. American Bridge designed and executed construction means and methods for both the approach spans and spandrel-braced arch. Temporary works for each cantilever consisted of two major items; the Stage 1 Support Tower and the Arch Tieback System. The Stage 1 Support Tower, founded on the gorge face, supported the first bay of arch to develop enough of the cantilever dead load prior to installing the Arch Tieback System. The Arch Tieback System consisted of a series of cables tied into the U0 Gusset Plates and was anchored into a guy tower system founded on the permanent abutment able to withstand the 1800 ton tieback demand of the arch cantilever, construction equipment, and environmental loading. These designs as well as the complete construction sequence and construction means and methods for the steel erection will be presented.