Publication Abstract

SuperPile 2017 Online Proceedings, (DFI)

Causeway and working platform design, construction, and instrumentation for TH 53
Jeff Segar, P.E., S.E.

This presentation discusses the design and safety aspects of a causeway constructed to serve as a working platform for a new bridge, that when finished, will be the tallest bridge in Minnesota. The causeway is 500 feet long and varies up to 120 feet deep, with 5 feet above the water line. The design of the causeway and the working platform had to be able to support varied surface loading from heavy construction equipment, shoring towers, drill rigs for the pier construction, and the Terex CC 6800 heavy-lift crawler crane as it lifts bridge girders some 200 feet in the air. The causeway crosses the massive Rouchleau Pit, an abandoned open-pit iron mine, which now provides the source water for a nearby city. Approximately 19,000 square feet of impervious membrane was used in the reinforced platform section, in addition to the geogrid layers, to contain possible spills and maintain the quality of the city’s water. The design of the causeway required aggregate that provided sufficient permeability to prevent the causeway from acting as a dam. Once constructed the permeability was verified by field tests and multiple types of instrumentation were used to monitor the performance of the platform and the causeway, providing confidence to the city, state, and contractors.

 article #2661; publication #1031 (SP-2017)