Although smaller, younger and somewhat remote from the commercial cauldron of the east coast which drove the great towers of New York and Chicago, San Francisco is home to four examples of International Modernism which would be outstanding in any city. All but one are in fact by the east coast-originating practice of SOM.

 

Completed in 1967, SOM’s Alcoa Building is an elegant glass curtain wall tower over a vast two-storey podium covering several blocks. Deploying a tighter, smaller scale variant of the external diagonal structural bracing used on the firm’s contemporaneous John Hancock Center in Chicago and later to become something of a signature, Alcoa appears particularly striking at dusk, when internal lightness from the office illumination balances the darkness of the steelwork.

 

The podium, containing car parking, presents a significant barrier to the street from all sides, but this inconvenience is eclipsed by the exquisitely designed and immaculately maintained public gardens on its roof.

 

Informed by SOM’s seminal Lever House from the previous decade, this elevated haven forms a base for the tower and is divided into quarters. The mixture of grass, planting and hard landscaping is tightly controlled and reminiscent of Japanese rock gardens, highly appropriate for the Pacific city.

 

Deeper inland and, at twice the height, dominating the central business district stands 555 California Street, finished two years after Alcoa. Designed by Pietro Belluschi, SOM and Wurster, Bernardi & Emmons and initially occupied by the Bank of America, the building’s striking facetted elevations with their irregularly-stepped tops were inspired by basaltic rock formations in the Cascade Mountains of northern California. It is clad throughout in rich, red carnelian stone, polished smooth.

 

The building occupies most of a city block but the bordering streets slope considerably. The complexities this fall of land creates is handled superbly. A piazza parallels Kearny Street, but round the corner in California Street itself, a sea of steps emerges as the road level drops. The main entrance is placed here. On Montgomery Street a much shorter annexe building, acting almost as a podium, contains a retail banking hall. Once more drawing from SOM precedents, this time the jewel box Manufacturers Trust Company Bank in New York, an immense open box, glazed at its upper levels, rises above a generous mezzanine reached by escalators.

 

A stepped passageway leads from Montgomery Street to a second entrance to the tower and to an external terrace which, thanks to the land levels mentioned, is above the main entrance on California Street.

 

An observation suite, accessed by admission to the Carnelian Room bar and restaurant, was housed on the 52nd floor from the building’s opening until its closure in January 2010. The glazed triangular bays arising from the facetted plan provided intimate, revelatory views over San Francisco and the bay.

 

Though undoubtedly formidable, 555 California Street works thanks to its location, original finish and attention to detail. It is a true landmark.

 

If San Francisco could be said to have an architectural logo, however, it would be the Transamerica pyramid. Moving into the 1970s, where design began to adopt more forceful shapes, its unique form appears at first a mere frivolity. Closer-to, though, it becomes clear that William Pereira & Associates’ remarkable structure is underpinned by intelligence and quality.

 

Firstly, it is a square-based pyramid bisected diagonally by the line of Columbus Avenue, which intersects its street corner plot. The famous tapering profile is both an aesthetic choice and a response to zoning laws, bringing daylight down to the street. It also provides inherent resistance to seismic shock, enhanced by a five-storey foundation, openwork lattice bracing above the second floor and additional internal structure.

 

The tower itself has 48 useable floors, the top-most featuring – as the owner’s website boasts – a 360 degree view from every point in the room. A decorative aluminium spire comprises almost a quarter of the building’s overall height, perhaps a faint echo of the classic New York Deco-era Chrysler Building.

 

As with 555 California Street, the pyramid uses a distinctive cladding system, namely concrete panels made with quartz-flecked aggregate. A rigorous, near constant, cleaning and maintenance regime retains the bright white finish, which reflects the setting sun beautifully.

 

Transamerica’s considerate shape means it never dominates the street, and its openness to sunlight benefits a lovely redwood grove and park next door. Built as part of the development and with as much care, it has a pond with delightful leaping frog sculptures and cleverly dissolves into the surrounding streets.

 

But perhaps the single best Modernist building in the city is the oldest of this quartet, also by SOM and finished in 1959: the Crown Zellerbach building, or One Bush Street.

 

Walking round the site, one discovers the complex piece by piece.

 

Paths shelve gently down from the street to circle a wonderful circular, single-storey pavilion, originally an American Trust Company bank, sitting snugly in a dell of sorts at the base of the tower.

 

As with almost all of the first generation of towers built under the principles of International Modernism, some sleight-of-hand is displayed in that what appears from the front to be a single tower is in fact merely the office accommodation; services are housed in their own tower to the rear. This is clad not in glass but in mosaic, here in a dark grey. Unusually, open balconies connect the towers at each floor level.

 

So generous is the distance between the bank and tower that it is not immediately apparent that they are part of the same development. That distance is filled with the extraordinary plaza, a wide open space one storey lower than the surrounding streets.

 

Here, the landscaping is the best I’ve seen in a building of this period, mainly because the plaza is in fact a bowl, a gently-sloped, seemingly natural occurrence in the streetscape, not an ugly rectilinear square stamped into the pavement like a die. That, the carefully-chosen materials – pebbles, grassy banks – and sloping pathways that wind in and out really make it work.

 

Bush Street reveals the main building’s superbly-handled entry, with a bridge taking pedestrians across the ‘moat’ of the plaza to a floating lobby. This is a crisp, clear, double-height, all-glass box placed under the main office tower and connecting to the service tower. It sits gently on a travertine slab that seems to levitate above the surrounding plaza. The detailing is phenomenal. Massive polished hardwood railings on thick travertine balustrades encircle the slab, making a good place to pause and survey the plaza. Cars enter underground around the corner.

 

This is a stunning building; clean and sharp and hugely impressive. The quality of the materials used in the design is evident, helped by what is clearly an exceptional maintenance regime. The concrete bridge, with its gently curved sides, and even the parking garage ramps are well integrated into both the building and the streetscape. There is subtlety, too – whilst the bank is more accessible from the street, the main tower retains a degree of controlled access via the bridge, the plaza here being a vertical drop from the street.

 

Fittingly, SOM's offices today lie opposite, and the firm uses Crown Zellerbach as a life-size training aid for new architects. Michael Duncan, design director at SOM, calls the building a “clean machine”, and speaks of it appearing as though “you can take it apart with a screwdriver”.

 

Together, these four buildings demonstrate the sheer style, commitment and craftsmanship that Modernism produced under the Californian sun.

 

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Posted 2010 after a week in the city