The complex consists of two buildings joined together at the base by a row of townhomes. The South Tower and North Tower rise 641 ft (195 m) and 495 ft (151 m) above the corner of Fremont and Harrison streets, respectively.[A][B] The North Tower contains 45 floors, while the South Tower contains 60.[A][B] However, because of the sloped nature of the Rincon Hill site, the South Tower's lobby floor or the First Street entrance is located on the sixth floor, and the first floor is five levels underground from the First Street entrance. The skyscraper is one of the most significant additions to the San Francisco skyline in over 30 years. It is also one of the tallest all-residential towers west of the Mississippi River, towering 697 feet (212 m) above San Francisco Bay.
One Rincon Hill South Tower towering over the San Francisco Bay
The crown of the South Tower contains a band of 25 LED floodlights that remain lit all night. Each LED light consumes little energy and has a lifetime of 40,000 hours. These lights are used to signal the weather, just like the lights on the John Hancock Tower in Boston. The crown glows red if warmer weather is in the forecast. A blue crown signifies that cold weather is expected soon. Green means that there is at least a 50 percent chance of rain. Amber indicates that the weather will remain unchanged. This is the San Francisco Bay Area's first weather beacon. The crown began lighting up on December 8, 2008.
In order to support the 60 story condo tower, One Rincon Hill South Tower will have a 12 foot (4 m) thick massive foundation embedded deep into serpentine rock. Although some engineers view serpentine rock with suspicion, there are massive structures, such as the Golden Gate Bridge, that have foundations on rock that is largely serpentine. Rising out of the foundation are the concrete core and large, tall columns of steel-reinforced concrete called outriggers. The core is attached to large outrigger columns by steel-buckling restrained braces that are designed to transfer building loads in an earthquake. These V-shaped restraining braces are said to act like a shock-absorber during earthquakes. The braces are also encased in a concrete and steel casing in order to prevent the braces from buckling and losing their strength. Many of these engineering technologies used in One Rincon Hill South Tower are new to the United States.
At the top of the building is a large tank, capable of holding up to 50,000 gallons (189,250 litres) of water, which will weigh 416,500 pounds (185,440 kg). A similar 50,000 gallon (189,250 liter) tank is located in the basement for firefighting purposes. There are two liquid damper screens in each tank to control the flow of the water in order to counter the sway from the powerful Pacific winds, which can sometimes reach hurricane-force.