Mt. Tamalpais High School Renovations
Mill Valley, Calif.

The 102-year-old “Mt. Tam” High School reopened May 25 after eight years of renovations. Thornton Tomasetti provided structural engineering to WLC Architects. The project featured the new Keyser Hall consisting of two steel-framed classroom buildings totaling 10,058 sf and 27,882 sf. Unique components included a 27-foot-tall tieback retaining wall and the “Classroom 2020,” which required special steel to support a large folding partition and several canopies, some of which are supported by canted columns. We designed the foundation system for the Olympic-sized swimming pool and associated concrete deck. The pool included two one-story wood framed structures (a 1,600-sf weight-room building and a 1,738-sf mechanical room building, both with wood shear walls). Due to the very low bearing capacity of the soil, these structures (including the pool and concrete decks) required deep foundations. An intricate network of grade beams, mat foundations and Auger Pressure Grouted Piers was used.