Retrofits take 'green' approach to concrete foundations

By Kathleen Maclay, Public Affairs


Crews put in a new foundation, made of 50 percent fly ash, at Wurster Hall. Arleen Ng photo

17 January 2001 | New foundations for the seismically retrofitted Wurster and Barker halls are so "green" they'll save the pollutant-emitting equivalent of 1.5 million vehicle miles, or 60 car trips around the Earth.

The foundations incorporate high-volume fly ash concrete, which requires far less fossil fuel to produce than conventional concrete. Fly ash is a byproduct of coal-burning power plants. The ash is created at high temperatures and becomes tiny, beady glass particles. Of the 60 million tons produced every year in this country, about 75 percent of fly ash is trucked off to landfills rather than converted into building material.

But enthusiastic design and construction teams working on Berkeley seismic projects say that the high-volume fly ash concrete mixture reduces environmental impacts and can save money while producing more durable concrete structures.

"Our main goal in these projects is to make sure that those who study and work in these buildings will be safe in the event of a major earthquake. That we can do so in such an environmentally friendly way is a wonderful bonus," said Chancellor Berdahl.

The projects are signs of the progress of "green" building techniques.

"The sustainable design movement is really taking off," said Wurster Hall retrofit architect Scott Shell of EHDD Architects in San Francisco. "We're excited that an institution such as UC Berkeley is willing to be a pioneer in this effort."

Every ton of standard cement produced for concrete requires about 1.5 tons of raw materials. Project architects and engineers said standard cement also requires intense use of fossil fuel, so much so that its production worldwide accounts for about 8 percent of all carbon dioxide emissions from human sources. That is the equivalent of 330 million vehicle miles or 330 million pounds of carbon dioxide, the primary greenhouse gas causing global warming.

Using fly ash in nearly 1,800 cubic yards of concrete at Wurster Hall will spare some of the greenhouse gas emissions that would have resulted from producing conventional concrete. Wurster Hall is home to the College of Environmental Design. The project there represents pollutant savings through the use of cement equal to 650,000 miles behind the wheel of a car, said Afshar Jalalian, a structural engineer with Rutherford & Chekene Consulting Engineers of Oakland.

About 2,500 cubic yards of 50 percent fly ash concrete will be also poured for foundations at Barker Hall as well, with comparable cost and environmental savings.

The two projects are part of the campus's on-going SAFER program, a multi-year $1 billion-effort to seismically strengthen more than a quarter of all buildings on the central campus to improve life safety in the event of a major earthquake.

Shell praised College of Environmental Design Dean Harrison Fraker and the college's faculty for being so supportive of, and informed about, sustainable design. Berkeley is also home to one of the world's leading experts in fly-ash concrete, P.K. Mehta, a professor emeritus of civil engineering.


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