Cathedral of Saint Mary of the Assumption

The Roman Catholic Cathedral of Saint Mary of the Assumption is the third church of such name in the city of San Francisco. The first, built in 1854, was abandoned when the congregation outgrew the space, and the second Cathedral was built in 1891. This structure burnt and was destroyed in 1962, and so the current Cathedral was commissioned and consecrated in 1971. It serves as a symbol of San Francisco's international urban status and caters to a multi-cultural congregation.

The Cathedral of Saint Mary of the Assumption in San Fransisco, designed primarily by Pietro Belluschi and Pier Luigi Nervi, is a structural feat of engineering and a bold Modernist design from the early 1970's. Despite its simple square plan, the roof of the cathedral rises into four parabolic hyperboloids, which are given a seeming weightlessness by their vertical separation from the floor and their lateral separation from one another. Four pylons raise the cupola, and brilliantly colored stained glass separates the cupola fragments, giving the nave a sense of effortlessness. The Cathedral is now one of San Fransisco's best-loved structures, and attracts many parishioners and tourists. Although the physical form was controversial to some upon its construction, Saint Mary's Cathedral is now a clear representation of the Modernist movement, evidenced by its radical use of precast concrete forms and non-traditional religious design.

1965-1970

Situated in the density of San Francisco's urban fabric, Saint Mary's Cathedral was and still is an integral part of the cityscape in Japantown near the city's downtown district. Geographically, it sits atop one of San Francisco's many hills, presiding over much of the city with a highly visible presence.

The Cathedral's cupola rests solely upon four piers in the corners of the sanctuary. Precast concrete triangular forms are used to distribute the load of the roof, and the piers are cast in place concrete, each carrying 10 millions pounds of pressure. These piers are only 24 feet in circumference at their narrowest points, and spread to wider dimensions above and below, reaching 90 feet to subterranean bedrock.

Although the Cathedral's modernist design was controversial upon construction, it is now widely loved by San Franciscans and tourists alike. The forward-thinking design is credited to architectural critic Allen Temko, who pushed locally hired architects Lee, Ryan, and McSweeney to envision a less traditional church design. It is at this point that internationally known Belluschi and Nervi were brought on to the design team. Today, both churchgoers and tourists praise the bold modernist form of the Cahtedral.

Saint Mary's Cathedral is one of many buildings of the Modernist movement to use prefabricated concrete. Structures got lighter and thinner, and Nervi took advantage of this in designing the triangular units that make up the cupola of Saint Mary's. The shifting unit types, comprised of 128 sizes and 1680 pieces, bear a resemblance to today's parametrically designed buildings, but was obviously constructed with only late 1960's technology. Nervi's design, while fitting within the structural Modernist movement, was still ahead of its time.
In 2007, the Cathedral was named to the AIA Top 25 "Gems of San Francisco" List.