The transportation sector accounts for a whopping 28% of all greenhouse gas emissions in the United States. Improving public transit is one of the best ways to cut that figure down – and the Transbay Transit Center stands to reduce CO2 emission by tens of thousands of tons each year. It’s also designed to serve as the terminus of California’s upcoming high speed rail system.
Construction on the center began in 2010 with the demolition of the former Transbay Terminal. During this process over 15 million pounds of steel were recycled, and 92,000 cubic yards of concrete were salvaged – that’s enough to fill 28 Olympic-size swimming pools. Excavation was completed earlier this year with the removal of 640,000 cubic yards of soil (much of which was recycled) over the span of four city blocks. The excavation site is so big that nearly two Transamerica towers could fit inside, and the dig uncovered relics of the past ranging from Gold Rush 49ers artifacts to human remains and even a mammoth fossil.
Next 60,000 cubic yards of concrete (with recycled fly ash content) were poured to secure the foundation, and groundwork was laid for the project’s geothermal system. The system will use the earth’s relatively low temperature to cool water, which will then be circulated through the building’s floors, substantially reducing the center’s energy use and cutting its water footprint by roughly 350,000 gallons each year.
Fast forward to today and the project is on schedule and on budget (after a few design tweaks), and the center’s structural steel framework is rising within the cavernous site. Turner Construction Superintendent Monique Hawn walked us through the building’s steel skeleton, which is robustly engineered to withstand virtually anything the seismically active region can throw at it.
When it’s finished, the lowest level of the center will house 6 interchangeable tracks that can accommodate Caltrain, Amtrak, and even high speed rail trains. Although the Golden State’s high speed rail plans are currently mired in bureaucracy, the Transbay Joint Powers Authority‘s stance is: “When it’s ready we’re ready.”
We’ll be closely following the center’s progress as above-ground construction begins this summer – stay tuned as we bring you a closer look at the project’s spectacular daylit interior, rainwater recycling system, and 1,400-foot long rooftop park.
Photos by Mike Chino for Inhabitat