Deep at the bottom of Lake Ontario sits the foundation for Toronto Hydro Energy Services' research anemometer tower. The tower's principal foundation feature consists of post-tensioned rock anchors constructed from atop a temporary platform during a brief calm weather period in March 2010 by Geo-Foundations Contractors Inc.
The six rock anchors - 2 at each leg of the 3-leg tower - are embedded 12.5 metres in rock with 3.0 metre free-stressing lengths. Rock drilling took place from atop a jack-up barge, using temporary casing extended from the drilling platform to lake bottom. After the tower was dropped in place atop the rock anchors, post-tensioning was completed using a team that included divers placing the jack at the bottom of the lake and a jack operator working at surface. The rock anchor tendons are 64mm / 1030MPa solid bar with Class II corrosion protection. All rock anchors were proof tested to 1330 kN and locked off at a permanent pre-stress of 1025 kN.
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