DESIGN AND CONSTRUCTION OF BNSF BRIDGE 18.79 OVER THE MISSOURI RIVER AT BELLEFONTAINE, MO

摘要

This paper will describe the design and construction of BNSF Railway Bridge 18.79 over the Missouri River at Bellefontaine, MO. The existing bridge was designed by George Morison and was his last high truss project over the Missouri River. The original bridge was constructed in 1893 as double track but operated with only one track in service. Construction of the new bridge approach and rehabilitation of the existing main span trusses started in March 2013 and work was completed in May of 2014. The main elements of this project include the replacement of a 700' long approach viaduct with new ballast deck plate girders spans, construction of a new deck floor system on four 440ft truss spans and the realignment and construction of 1000' of track on each approach embankment. Other key aspects of this project included the use of an innovative hybrid foundation system and a unique erection scheme for assembling and installing the new approach spans. The foundation system consisted of micropiles encased within a short drilled shaft; which minimized the potential for movement of the existing tower bent foundations and served as an economical alternative to conventional drilled shaft construction. The erection scheme used to install the new approach bridge required 120ft long steel deck plate girder spans to be erected and assembled roughly 30ft in the air on top of falsework. This scheme was developed in response to the limited access, right-of-way and environmental constraints at the project site.