Replacement of the Amelia Earhart Memorial Bridge US-59 Highway Over the Missouri River Atchison, Kansas

摘要

The Kansas Department of Transportation and Missouri Department of Transportation are currently working on the design phase of the replacement of the US-59 Bridge over the Missouri River. At this time there are two structural designs: one a Tied Arch and the other is an Overhead Truss. The design and construction of this structure presents several Geotechnical Dilemmas. The foundation material for the structures both new and existing is the Weston Shale Formation. The Weston is problematic shale that contains several Paleosols and deposits of kaolinitic clays. Thick discontinuous near shore sandstone deposits are also common with minor inclusions of limestone and coal seams. The Weston Shale does not become a better foundation material with depth! Even the most competent of layers (Qu values of 100 tsf) can be underlain by material the strength of weak clay. The Bridge Foundation Geotech investigation for this structure will consist of core-holes and power auger soundings of which a minimum of 10 will have to be conducted from a barge set up. A Geophysical Study of the proposed river piers will also be done. This study will entail: seismic reflection, sub-bottom profiling, side-scan sonar and a single beam echo-sounder. Also included in this investigation was the first ever 3 cell Osterburg Test. This test was done to mimic the bedrock conditions we will encounter with the proposed drilled shaft group foundation elements. There will still be several problems facing the geotech section of KDOT during the design, and construction phase of the project. The most problematic will be the design and construction of drilled shafts in an ancient glacial river environment.