Steep slope foundation for “H” frame structure

Crux has been selected to provide 100 percent design-build foundation services on the Lansing-Harmony 161 kV transmission project in northeast Iowa.

The project entails replacing approximately 120 wood “H” frame structures with steel “H” frame structures along a 50-mile alignment, which traverses rolling hills and private properties.

Teaming with M.J. Electric, Crux will design and construct foundations for one steel “H” frame structure and an adjacent 60-foot by 30-foot steel maintenance platform.  Both structures are located on a 45 degree slope and will require helicopter transport for all materials, equipment and personnel.  Site-specific geotechnical data was not available for these structures because of the challenging location, leading to the selection of micropile foundations.  Micropiles can readily adapt to variable subsurface conditions and are well suited for helicopter transport.  The “H” frame structure will employ bolted steel pile cap connections.  Crux crews will mobilize in early June and expect to be onsite for two weeks.

ITC Midwest commissioned the rebuild to improve the capacity of the electric transmission system in the area, and to meet increasing national reliability requirements.  Construction began in September 2012 and is expected to be completed in June 2013.