California Tower is a residential mixed use development that consists of 56 stories tower and 9 stories podium with 3 levels of below grade parking structure. The project residential program includes 116 for sale condominiums, 280 market rate rental unit and 150 rent restricted unit serving households earning up to 50% area median income (AMI) as published by the mayor's office of housing and community development (MOHCD).

The tower is equipped with amenities located at 7th floor, 31st floor, and 32nd floor. Amenities in 7th floor include fitness center, pool, and associated support spaces, such as a library, meeting room space, and the main leasing office for the building. At 31st and 32nd floor, amenities are located on the east side of the floors that encompasses dining area, show kitchen, wine room, media room, and a gaming room. This tower also has three terraces located in 5th, 7th, and 9th floor for building occupants. Mechanical and electrical are housed in the rooftop penthouse located at 56th floor.

Site Plan and Building Location

Located in Northern California, California Tower is part of the master development that consists of 11 other community developments. California Tower classifies as Transit Oriented Development (TOD), where the development is located within a half-mile of quality public transportation. Other than the convenient transportation system, California Tower also overlook the bay on the east side.

Zoning

Located in the commercial district area, California Tower is categorized as Downtown Commercial District, which includes the requirement for housing as well as office space.

Building Code and Standards

California Tower is built with accordance to:

2013 California Building Code
2013 California Electrical Code
2013 California Mechanical Code
2013 California Plumbing Code
2013 California Energy Code
2013 California Fire Code
2013 California Green Building Standards Code
2013 California Referenced Standards Code
2013 California Housing Code

The facade of the building is divided into four main materials: metal panel, storefront glass, curtain wall, and masonry. Metal panels are located on the east elevation of the building from 1st - 6th floor where they are used to cover the soffit created from the facade offset. Storefront glass is located only on the 1st floor of the building.

California Tower utilizes unitized curtain wall system where each curtain wall unit is stacked on top of each other. Masonry is only used on the first six floors of the south and west elevation.

Sustainability Features

With the intent of pursuing LEED Silver rating, California Tower is designed to be sustainable. Featuring recycled materials and materials sourced from local regions, the construction of California Tower also ensures good air quality control as well as using low-emitting materials.

Glazing

The glazing system encompasses insulating glass units with a dual-seal system that consists of two lites of glass, a primary seal of polyisobutylene. All glazing units have maximum U-factor of 0.55 BTU/ sq ft as specified in NFRC 100. The solar heat gain coefficient for the glazing units is 0.28, as specified in NFRC 200.

Roofing System

Roofing system in California Tower consists of 2 ply Styrene-Butadiene-Styrene (SBS). The system is composed of five basic components: Insulation, modified base sheets, modified bitumen membranes, adhesive, surfacing, and flashings. The system can resist thermal shock and has superior fire resistance. California Tower also has overflow drain assembly that serves as redundancy in the event of a heavy thunderstorm.

Building Enclosures

Structural

The superstructure of California Tower is predominantly post-tensioned flat slab with concrete core shear wall. The gravity system of the building is divided into two different types: reinforced concrete and post-tensioned slabs. Reinforced concrete flat slabs are used in the structure below grade. For the structure above grade, 8" thick post-tensioned flat slabs are used. The lateral force-resisting system consists of coupled special concrete structural shear walls, which are supplemented by wing walls at the lower levels to enhance the overall stability of the tower. The coupling beams are reinforced with either diagonal reinforcement or steel-reinforced composite steel coupling beams. The building utilizes 4'-0" thick mat foundation. The foundation bears on dense Colma Sands, 34-39ft beneath the surrounding grades.

Mechanical

The building mechanical system utilizes two cooling towers located on the roof. The cooling tower is connected with the chilled water system from the ground and is controlled with Variable Frequency Drive (VFD) to ensure efficiency. Each residential units are equipped with heat pumps that serve as both cooling and heating purposes. Depending on the size of the units, the supplied CFM varies from 525 to 1,400. The air distribution is mainly through sidewall and ceilings. All mechanical system in California Tower complies to Title 24 of California Energy Code.

Lighting/Electrical

The lighting system in California Tower predominantly features LED light fixtures in the residential units. The electrical system comply with California Energy Code Title 24.

Smoke Control

The smoke control used in California Tower complies with California Building Code. The lobby area is constructed with 1-hour rated fire partitions. All units on the floors will be separated from the corridor with 1-hour rated fire partitions. The walls will also be designed as smoke barriers. All the doors in the residential corridors are smoke tight with gaskets at the tops and sides. Each residential units will have operable windows. All the residential corridors will be an active smoke zone, which will be negatively pressurized upon detection of smoke within the corridor.

Construction

The construction methods feature construction waste recycling. The construction of California Tower uses low-emitting and and recycled content materials.

Geoffrey Tanudjaja

Structural Option

Dr. Thomas E. Boothby, P.E., RA

General Building Information

Project Team

Architecture