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East Bay Entrepreneurs Unveil Quake-Dampening Foundation

The Oakland Tribune – BUSINESS DAY

A former UC Berkeley architectural professor, a Danville home builder and an Oakland civil engineer unveiled a low-cost house foundation system Wednesday that can ward off serious damage in a major earthquake.

The so-called “damped-sway on system,” a steel-foundation using steel screw piles and large shock absorbers, will be the base for a prototype $400,000, two-story home being built on Chabot Road in the Oakland hills by architect and historical preservationist Randolph Langenbach.

Although the system is far from proven and some engineers questioned whether such a system was needed for a home, the designers say the new foundation can help a new house resist a magnitude 7.5 quake with little or no damage for only about $15,000 more than a normal foundation.

“It acts as a shock absorber to take as much as 75 percent of the force of a quake.”

“It acts as a shock absorber to take as much as 75 percent of the force of a quake.”
“It acts as a shock absorber to take as much as 75 percent of the force of a quake,” said Gene St. Onge, an Oakland civil engineer who helped design the foundation.

The prototype 2,100-square-foot home will replace the house Langenbach lost in the 1991 Oak-land-Berkeley hills firestorm. The site lies about a quarter-mile from the Hayward Fault.

The foundation was designed by Langenbach, St. Onge, Counterquake Corp. of Redwood City and David Fowler, owner of Danville-based Pacific Housing Systems. The foundation uses a frame of steel beams resting on six 4-inch steel helix anchor piles drilled 15 to 20 feet down into bedrock. The pillars allow the house to sway up to 4 inches in any direction. Pacific Housing has successfully used a similar steel pillar system for homes it has built in the last 12 years, Fowler said.

The metal frame itself is attached to 4-foot-long dampers that are of the same type used in other heavy duty applications such as for huge battleship cannons, Fowler said. As the house sways, the dampers act as shock absorbers.

The designers, who have invested about $40,000 in research and development and are thinking about forming a venture, hope the system attracts the attention of home builders and insurance companies.

Tony DeMascole, a San Francisco civil engineering consultant, said the foundation is basically a base isolation system that is a proven seismic construction and retrofitting technique for larger buildings such as Oakland City Hall, which had more fragile materials that could not be strengthened.

– By Benny Evangelista – STAFF WRITER