The proposed Aura Tower project in downtown Sacramento, California consists of a 38-story condominium tower with 262 units. Torque Down 1275 piles were selected for this project to minimize noise and vibration within the project vicinity.

Project Conditions

Subsurface conditions varied across the site. Most of the site was underlain by a dense gravel layer. However, the gravel layer was not present at a portion of the site, resulting in varying pile capacities depending on pile location. Where present, the gravel layer was generally overlain by alluvial deposits and fill.

Test Pile Program

Production pile installation procedures and allowable design capacities were determined through an indicator and test pile program. Production length piles were tested to an ultimate capacity of between about 500 and 800 kips. A shorter pile was also tested to an ultimate capacity of 360 kips. Eight piles installed to different depths were load tested at the site. Piles were instrumented with strain gauges, which indicated that 80 percent of their capacity was achieved through friction.