Success Story Details
A New Twist To The San Francisco Skyline
One of the final developments in the project, 160 Folsom, will be a 39-story building with 393 units and include 237 market rate condominiums and 156 affordable rate condominiums.
A twisty design to a new 39-story skyscraper adds to the Transbay Redevelopment Project
STURTEVANT, WI (Aug. 1, 2018) – San Francisco is a city that prides itself on its neighborhoods, and the Transbay Redevelopment Project is bringing life to blocks that were once covered by freeway ramps. The redevelopment project’s goal is to bring retail space and affordable housing to the new neighborhood, which is close to public transportation. One of the final developments in the project, 160 Folsom, will be a 39-story building with 393 units and include 237 market rate condominiums and 156 affordable rate condominiums. Designed by Studio Gang Architects and developed by Tishman Speyer, the building will be a twisty sight that towers over the Transbay neighborhood. Interstate Concrete Pumping was selected for the concrete placement work, and they brought their Putzmeister MXR 28 and MX 34/38Z placing booms, 56Z-, 61-, and the new 63Z-Meter boom pumps to the job site.
Crews broke ground on 160 Folsom in May 2017 and began pouring concrete in December of the same year. Construction began with pouring the underground parking structure. The base of the lower level was an 11,000 cubic yard (8,401m3) mat pour. To keep in line with the construction timeline, the crews and equipment were tasked with long pour schedules. The equipment was required to handle large volume pours for up to 12 hour timeframes. Interstate used a collection of boom pumps to be able to reach the mat including three 56Z, one 61 and the new 63Z-meter boom pumps.
Because the tower is located on a congested city block, two blocks from the San Francisco Bay, the job site is only accessible from two sides. The new 63-meter boom pump features a three-section outrigger design that minimizes the outrigger footprint and increases maneuverability, saving space in the congested job site. The extra range of the 63-meter boom gave the pumper the ability to reach the opposite side of the mat from one side of the job site.
“Our new 63Z gave us the extra reach we needed to comply with the restrictions of the job site,” said Andy Paulazzo, President of Interstate Concrete Pumping. “It has been a key to the success of the job thus far.”
As construction continues, the pumper will switch to a MX 34/38Z placing boom to reach the new heights in the twisty tower. The 34/38 placing boom was set up using a climbing system within an elevator core to allow the pump to move up as the building grows. Also on found on the site, a 1987 MXR 28 was set up as a freestanding tower reaching heights of 50 feet (15m). The placing systems allow for contractors to continue pumping concrete from ground level to the upper levels of the skyscraper.
“The Putzmeister MXR 28 is over 30 years old and it still competes with the rest of our fleet,” said Paulazzo. “The boom operates as efficiently as the other placing boom on the job site.”
More than 250 pours will be made with a total of 46,160 cubic yards (35,292m3) of concrete poured when Interstate has finished the job.
Chicago architect Jeanne Gang of Studio Gang Architects designed the tower to pay tribute to the classic bay window design that is common in the San Francisco area. The design is meant to provide texture to the exterior of the building and create “visual noise” to discourage birds from flying into the building.
The twisty tower was originally planned to be 100 feet (30m) shorter but after months of negotiation the tower’s extra height was proved to be beneficial — architecturally and economically. The tower has been approved to be 400 feet (122m) tall to add extra condominium space.
“Even with the elaborate design of the building, our equipment has provided us with the ability to maneuver the job site with ease,” said Paulazzo.
Boom pumps, in conjunction with placing systems, have given the contractor the ability to set up with a minimal footprint on the congested job site and provided them with a variety of options for pouring the lower levels of the new tower.
Standing tall, the tower will include 6,500 square feet (604m2) of open space on three rooftop decks, central courtyard, and 9,332 square feet (867m2) of retail space on the first floor in addition to the 38 floors of market rate and affordable rate condominiums. The underground parking structure will give tenants 334 parking spaces with an additional 150 spaces for bikes.
A few hundred feet shorter, the 160 Folsom site will contain two smaller podiums. The 6-story and 8-story podiums will provide more below market-rate condominiums.
Much of the Transbay Redevelopment buildings are working towards a certification in Leadership in Energy and Environmental Design (LEED). The LEED system is built on ratings given by the United States Green Building Council (USGBC) to evaluate the environmental performance of a building. Projects are given points during construction and use of a building for environmentally friendly actions. The points are added up to determine the level of LEED Certification. Currently, 160 Folsom is targeting LEED Gold certification, which requires the building to score between 60 and 79 points.
Using concrete in the building process can increase the number of points a building can earn for a variety of credits. For example, underground concrete parking garages can reduce the overall building footprint due to less paved areas, creating more open spaces. This credit is worth one point towards LEED certification. Using concrete in the building process allows for the project to earn between 19 and 28 points.
The Transbay Redevelopment Project is a step toward reaching Mayor Ed Lee’s goal of providing 10,000 affordable housing units to the San Francisco Bay Area by 2020. The project is well underway with two projects completed and five projects currently under construction. 40 percent of 160 Folsom’s condominiums will be designated below market rate, and affordable to families earning 80 percent to 120 percent of the area median income.
The equipment chosen for the skyscraper’s intricate design provided contractors with the ability to reach the demanding heights of the tower from only two sides of the job site, set up in a congested city, and the durability of pouring for long hours at a time. Interstate’s line-up has stood the test of the twisty tower’s demands, and is keeping construction on schedule.
Owner: Block One Property Holder, L.P. – Delaware
Developer: Tishman Speyer – New York City, New York
General Contractor: Lendlease – Chicago, Illinois
Ready-Mix Supplier: Pacific Structures – San Francisco, California
Concrete Placing Contractor: Interstate Concrete Pumping – French Camp, California
Equipment: Putzmeister MXR 28 Placing Boom, MX 34/38Z Placing Boom, Placing Tower System, 56Z-Meter Boom Pump, 61-Meter Boom Pump, 63Z-Meter Boom Pump
Crews worked long hours to keep the project moving and are on schedule, pumping 738 cubic yards (564m3) per hour to finish the mat pour.
Putzmeister's new 63Z-Meter features the three-section front outrigger leg design, which helped in keeping a minimal footprint on the congested jobsite.
Several boom pumps were used at one time to pour the mat for the underground parking structure including three 56Z-, 61- and the new 63Z-Meter.
Over 250 pours will be made, totaling 46,160 cubic yards (35,292m3) of concrete when Interstate Concrete Pumping has finished the job.
Pouring an underground parking structure adds a point towards the LEED Gold Certification for 160 Folsom.
The 400-foot (122m) tower stands tall with Studio Gang's twisty design. Rendering courtesy of SteelBlue, LLC.