SME played a vital role in bringing renewable energy to the State of Michigan. Our client, ITC Transmission (ITC), made a major investment in the high-voltage electric grid by developing a new 140-mile double circuit 345 kV overhead transmission line and four new substations across Michigan’s Thumb through Tuscola, Huron, Sanilac and St. Clair counties. Constructed in three phases, the line and substations helps increase transmission system reliability, reduce system congestion, provide more efficient transmission of energy, and serves as a “backbone” for future interconnection of new generation sources in the area, particularly wind energy from wind farms in the Thumb. This transmission line will provide renewable energy to power over 350,000 homes

SME has been active during all three phases of the four electrical substations and transmission line design, construction and installation. The transmission line consisted of over 800 total structures, mostly monopoles that stand over 150 feet tall, generally spaced between 800 and 1,100 feet apart, with about six structures per mile. To build a safe and reliable line, ITC’s engineers needed to know and understand all the important characteristics of the land where the line would be built. SME’s Geotechnical Team provided over 180 soil borings along the three preferred routes to identify subsurface conditions at proposed monopole foundation structures for the transmission line; and 27 soil borings at monopole structures and for the electrical substations.

Using a drill rig with varying drilling techniques, we obtained samples of the soil every few feet to depths up to 65 feet. Access to the boring locations required careful coordination with ITC land agents and numerous landowners. The samples were then returned to our laboratory for analysis and testing. SME’s geotechnical engineers helped determine the type and size of foundation needed for each pole and substation location, clearing the way for final design. SME also conducted field electrical resistivity testing at most boring locations for the transmission structures and substations.