Once completed, this 61-story, 1,070-foot skyscraper will have used close to 100,000 cubic yards of concrete. For the mat foundation, more than 130 ready-mix concrete trucks from Cemex plants in the San Francisco region performed an 18-hour pour to supply 7,300 of the approximately 12,000 cubic yards of concrete required for the job. This was the second largest mat pour in the history of the city.
The main challenge for the concrete contractor, the pumping company, and Cemex was carefully coordinating supply, pumping, and placing highly sensitive 10,000 psi self-consolidating concrete (SCC) into the core walls of the tower. The early strengths of the SCC allowed the concrete contractor to use a form system that was raised in two to three days. High-strength lightweight concrete was also supplied for most of the floors. Pumping and placing concrete at these record heights in the Bay Area marked a milestone achievement.
The SalesForce tower was a repeat performance as Conco, the concrete contractor, participated in two of the largest pours in California’s history. In April 2014 the company placed 21,200 cubic yards for a foundation that will support the Wilshire Grand, a 1,000-foot high-rise in Los Angeles. Together, the two skyscrapers will not only be the tallest structures in their respective cities, but also the two tallest buildings west of the Mississippi River. Conco is getting closer to their final pours of concrete to complete all concrete placements, which began in November of 2015. While the culmination of the project will occur in 2018 when the tower is completed, the planning goes back nearly a decade.