Bridge 370.7 is 3-span 480' single track tangent bridge near the small town of Ferry, Alaska. 2-200' open deck trusses span the Nenana River. The river has a history of meandering, and shifting its attack angle at Pier #3, which resides near the middle of the river. The current 45 degree attack angle has caused significant scour on the upstream end of the pier, warranting pier replacement. Design for ice drift and meticulous planning with construction proved this to be an interesting and noteworthy pier replacement project. Part One (Design) of this paper will provide an overview of the structural approach, design, and lessons learned for the pier replacement, focusing on the design for ice drift. The paper will specifically explore . the appropriateness of the AREMA Chapter 8 Group VIII load combination factor of 1.4 in context of this particular project. Part Two (Construction) of this paper will highlight successful methods used to construct primary substructure elements, such as 7.5' diameter drilled shafts (via the wet-hole method) and phasing to install steel girder-caps to support the trusses.
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