In the late 1960s, when Structural Engineer Walt Hensolt and his team at Chin & Hensolt helped design San Francisco's Transamerica Building, Structural Engineers were just beginning to use mainframe computers and early-stage software to assess the effects of earthquake forces on building structures. Before then, most skyscrapers were built like tall rectangular boxes and Structural Engineers used slide rules and other mechanical aids to design them. Even a handheld calculator was still a thing of the future.
The Transamerica Building may have been one of those perfect marriages of art and science: a concept that pushed the envelope of design brought into being by technology that pushed the envelope of structural engineering. The solution was the selection of an unconventional design, one that would require thinking beyond the box. The Transamerica headquarters, with its tall pyramid-like tower, is one of the most recognized and celebrated skyscrapers today.
It all began in 1968 when then company President John R. Beckett wanted to allow natural light and fresh air to filter down to the streets around his new headquarters. The result: a refreshing openness that allowed access to the environment.
To ensure that this tallest building in the San Francisco skyline would perform well and survive future earthquakes, Hensolt used a 3-D dynamic computer model. It was one of the first times that this technology was used on a skyscraper. After consulting with academics and steel industry experts, he developed specialized welding sequences for the structure's complicated connections. This was done to ensure their integrity and to preclude fracture due to the intense heat of welding. This became one of the basis upon which modern welding codes were written.
When it was under construction, the Transamerica Building was also making history. At that time, it was the largest single concrete pour for a foundation ever in San Francisco. The thickness of the concrete mat foundation totaled nine feet. The base includes approximately 16,000 cubic yards of concrete, encasing more than 300 miles of steel reinforcing rods.
The building includes 48 floors with the largest floor on the fifth level. The smallest floor, not surprising, is the 48th, measuring only 45 feet per side and containing 2,025 square feet of space. The building's height reaches 853 feet, including the 212-foot spire. Today, there are more than 1,5000 people employed by more than 50 firms working in the Pyramid.