Digging Deeper: L.A. Courthouse’s Cantilevered Cube

Thanks to a structural-steel hat truss, the 10-story tower of the 240-ft-tall New United States Courthouse, Los Angeles, appears to balance on its core, hovering over the ground as if it were a sculpture on a pedestal.

“In a typical building, you have perimeter columns that meet the ground,” says Mark Sarkisian, structural and seismic engineering partner in the San Francisco office of the project’s architect-engineer Skidmore, Owings & Merrill LLP (SOM). “In this case, those perimeter elements don’t reach the ground,” he adds. They stop at the second floor.?