When the 1906 earthquake struck San Francisco, most of the buildings at the time in the city were made of wood (like redwood harvested from the once vast stands of coastal redwood that grew in Northern California). This did not bode well for San Franciscans because immediately after the earthquake, a series of fires spread quickly over the city, largely razing to the ground almost every wooden structure that withstood the tremblor.
But curiously, a few structures did survive largely intact. Among them, are the Old United States Mint (also known as The Granite Lady) and a half-finished warehouse built for the Bekins Van and Storage Company at Mission and Thirteenth.
The Bekins building survived because it was made of a relatively new material that had largely been ignored (and vigorously opposed) in California. That material is reinforced concrete.
A problem with concrete is that it has great compressive strength. It can withstand high pressure without cracking. But it lacks tensile strength, meaning it cannot bend without shattering. Throughout the late 1800s, various builders tried to strengthen concrete with metal, mostly iron. With the advent of steel, which was becoming increasingly cheap to manufacture, and with a new technique based on twisting the metal to allow it to adhere better to the liquid concrete, a new era of construction was born.
In the years before the 1906 earthquake, the use of concrete was resisted by the legions of bricklayers, masons and powerful builders’ unions that saw in the material a threat to their survival. Others called the material ugly and not worthy of a great city like San Francisco.
One trade publication at the time wrote: “a city of the dull grayness of concrete would defy all laws of beauty. Concrete does not lend itself architecturally to anything that appeals to the eye. Let us pause a moment before we transform our city into such hideousness as has been suggested by concrete engineers and others interested in its introduction.”
The resistance against concrete was formidable enough that the material was not used widely in the city. Even after the earthquake, it took a while for people to grasp its value. Despite the overwhelming evidence that this new building material could dramatically help a city not only withstand an earthquake but fire as well, San Francisco building codes still forbade the use of concrete in high, load-bearing walls.
It wasn’t until two years later, in a contentious San Francisco board of supervisors meeting, that the city changed its building codes to allow the widespread use of reinforced concrete. By 1910, the city had issued permits for 132 new reinforced concrete buildings. The science of building advanced hugely in the wake of the disaster.
Today, most every tall building in the world makes use of steel reinforced concrete. The survival of the Bekins building was transformational for not only the city of San Francisco but in many ways, it heralded a watershed moment in the history of architecture, construction, and the planet’s cities.
by Erik Olsen