Milestone involves 888 concrete trucks, 8,218 cubic yards of concrete and 2.5 million pounds of reinforcing steel
SAN FRANCISCO – The Balfour Beatty US California Division has successfully completed a concrete pour consisting of 8,218 cubic yards of concrete at the 42-story Transbay Block 9 residential tower project site at 500 Folsom St. in San Francisco. The amount of concrete poured is equivalent to 32 miles of a four-foot-wide sidewalk. The non-stop pour started at 1:59 a.m. on Saturday, June 17 and concluded at 1:56 a.m. on Sunday, June 18. The milestone marks the largest concrete pour on record for the company’s California vertical construction business unit.
Forty-five trucks, driven by 90 drivers on alternating schedules, delivered 888 truckloads of the concrete to five concrete pumps strategically located on the project site. The pour covered a 30,000-square-foot surface area to form the mat foundation situated 75 feet—or six floors—below the ground surface. Concrete thickness of the mat foundation ranged from 10 feet beneath the tower to five feet outside the tower. The mat is also comprised of 2.5 million pounds of reinforcing rebar.
A total of 53 craft workers, supervised by Balfour Beatty staff with rotating shifts, completed the work without interruption over the course of a 24-hour period. To meet the company’s commitment to sustainability, the team used concrete comprised of 40 percent fly ash, a cement replacement, and recycled water in its production process. Fly ash is an environmentally-friendly solution that meets or exceeds concrete performance specifications, and is recognized by the U.S. Green Building Council’s LEED® rating system as a post-industrial recycled material.
The massive effort involved a detailed logistics and coordination plan working alongside multiple partners including Balfour Beatty’s structural concrete contractor, Webcor Concrete Group, as well as the City of San Francisco’s building, traffic and police departments. To keep the public informed in advance of the planned activity, the project team distributed a newsletter to surrounding neighbors describing the event and the potential for increased noise and traffic. Street signage with detour and street closure information was also posted two-days prior to commencing.
Balfour Beatty senior vice president, Chet Brians, said precise timing and coordination was key to the operation’s success. “Every detail was meticulously planned to ensure our teams were 100 percent prepared to execute the non-stop work,” said Brians. “Even the slightest delay leading up to the scheduled pour could have significantly impacted the execution of this multifaceted job. I’m proud of our team and the collaborative effort that it took to accomplish this extraordinary feat.”
The new Transbay Block 9 residential tower is being developed by Essex Property Trust, Inc. and designed by lead architect SOM in collaboration with Fougeron Architecture. Expected to complete in spring 2019, the project scope features a tower flanked by two lower podiums that will house 436 market rate units, 109 below market rate units, shared open spaces and amenities, and retail along Folsom Street. Although it will be constructed as one building, Transbay Block 9 will have the appearance of two low-rise buildings bracketing a high-rise tower. The basement will feature six below grade parking and mechanical levels with a total of 288 parking stalls.
About Balfour Beatty US
Balfour Beatty US is an industry-leading provider of general contracting, at-risk construction management and design-build services for public and private sector clients across the nation. Performing heavy civil and vertical construction, the company is the US subsidiary of London-based Balfour Beatty plc (LSE: BBY), a leading international infrastructure group that finances, develops, builds and maintains complex building programs focused on social and commercial buildings, power and utility systems, and transportation. Consistently ranked among the nation’s largest building contractors, Balfour Beatty US is the No. 6 Domestic Building Contractor as ranked by Engineering News-Record. To learn more, visit www.balfourbeattyus.com and www.bbiius.com.