Hearst Mining Building marks retrofit milestone
Campus landmark, at 95, now rests on earthquake-resistant base-isolator system

By Diane Ainsworth, Public Affairs

At a Jan. 11 ceremony, Chancellor Berdahl releases the last wooden beam supporting Hearst Memorial Mining Building. The 60-milion-pound landmark now rests on a state-of-the-art base-isolator system developed by Berkeley engineers. Peg Skorpinski photo

16 January 2002 | Pushing a button to release the last of 700 wooden beams supporting the Hearst Memorial Mining Building during its seismic retrofit, Chancellor Robert Berdahl on Jan. 11 congratulated the workers and managers who helped achieve a technical milestone in the building’s history.

“The historic significance of this moment is preserving what I think is by all measures the most beautiful building on this campus,” Berdahl said before donning a hardhat and walking down a muddy path to release the support. “This is really a great moment for us all.”

The building, which weighs 60 million pounds, was nestled on its new base isolators, a foundational grid of 134 cylindrical isolators that will allow it to move two feet in any horizontal direction to dissipate energy released by an earthquake. The 95-year-old unreinforced masonry building was a prime candidate for seismic retrofitting, sitting just 800 yards from the Hayward Fault.

Engineers from Rutherford & Chekene, the structural and civil engineering firm on the project, estimated that the building, on its new seismic foundation, will be able to withstand a 7.0-magnitude earthquake without suffering significant damage.

When renovation is completed later this year, the building will be a world-class center for materials science and nanotechnology research and teaching, said Paul Gray, executive vice chancellor and provost. “It will form an important basis of California’s economy going forward,” he said.

The $68-million seismic renovation project, launched three years ago, uses “base isolation” technology pioneered by Berkeley engineers more than 25 years ago. The seismic isolation system is an increasingly common method of protecting buildings against earthquake damage. San Francisco’s City Hall and Court of Appeals, as well as Oakland’s City Hall, have been seismically upgraded with base isolators.

Each stainless steel and rubber isolator weighs 5,300 pounds.
Thirty-four dampers have been interspersed throughout the waffle-like grid to act as shock absorbers that will slow movement from ground motion in an earthquake.

Originally opened on Aug. 23, 1907, the Hearst Memorial Mining Building was built with funds donated by Phoebe Apperson Hearst as a memorial to her husband, Sen. George Hearst. Hearst had made his fortune in the silver, gold and copper mines of the western U.S.

Architect John Galen Howard designed the four-story building in a vigorous reinterpretation of 19th-century structural aesthetics. Howard endowed it with a lobby, Memorial Hall, that is set off by delicate columns, lattice girders, skylight domes and pendentives filled with Guastavino tile. The renovation project preserves and restores those features and some of the building’s original interior courtyards. In addition, the renovation work has included the construction of two modern additions to the north side of the building. The next phase of renovation will involve installation of new mechanical, electrical and plumbing systems and continued restoration of the interior woodwork.

The landmark structure is expected to reopen in June to a limited number of offices and classrooms. When fully restored, the building will house state-of-the-art research and teaching laboratories, classrooms and offices for the College of Engineering’s materials science and engineering department, plus a major nanotechnolgy lab.