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Waiting for the Big One

New "1-G" House Rising to Stand Up to Major Quakes

Daily Pacific Builder (Vol. 111, No. 123)

CASTRO VALLEY- The Big One hits tomorrow with a rumble and a roar and a force that jolts and sways your home with savage violence.

If you live near a major fault in quake-prone California, you could be looking for a roof over your head at the nearest emergency shelter.

Anton Bley is looking at another scenario. After a 7.4 jolt on the Richter scale, he expects to continue sleeping at home, a scant six miles from the Hayward fault on his 128-acre ranch near Castro Valley.

Damage? Probably some cracks to repair and a few leaks to plug from pipe separations.

With a background in architecture and contracting, Bley says he was looking for a home that would be fireproof against summer grass fires and have the material strength to resist quakes.

It was building my own home that got me interested in this,’ he says of the Insulated Concrete Form (ICF) design. ‘Now, it’s open house every day here at the building site for anyone who is interested in seeing an ICF home go up.”

The Bley home is the first, according to its owner, to utilize an innovative building process combining “1-G force” design with ICF construction. The “G” equates the weight of a building with force – a 4-ton building to withstand a 4-ton force.

At a glance, no one will suspect the dramatic, 3,2OO square-foot, five-room, 1 1/2 bath ranch-style home is designed to be “7 times tougher” than current building codes demand and to remain ‘occupiable” after a 1-G force earthquake.

Construction of the home employs American Polysteel Insulating Concrete Forms. Stay-in-place foam forms supply insulation. Reinforced concrete supplies both insulation and strength.

The Bley home takes into consideration potential quake magnitude, employing a post and beam design with concrete support piers plunging 16 feet beneath the surface. The North Hayward Fault near the Bley residence could generate a 7.3 to 7.4 Richter quake.

Gene St. Onge, Oakland civil and structural engineer for the Castro Valley 1-G structure, says it follows the building industry trend toward “performance-based” design.

Up to the present, engineers have been required only to meet minimum code requirements providing for ‘life safety’,” he says.

“…a building can be designed to survive a major earthquake with minimal damage…”

“This means the condition of the building after a major quake is not considered – as long as it can stand while occupants escape safely.”

St. Onge says a building can be designed to “survive a major earthquake with minimal damage by considering the estimated force that would actually be exerted on it.”

Even with a stricter 1997 building code becoming effective in July. Residential designs need not resist full 1-G force. Forces designed into the Bley home would be several times more than required by present codes.

Reinforced concrete resists quakes, he says. “With a little more concrete reinforcement and strengthening of the roof and floor- and not that much more expense- a structure can be designed to withstand major quake damage using the ICF system,” St.Onge predicts.

How much does this protection add to the cost of a home? “It’s initially more expensive to build, but the savings from reduced energy costs generated by ICF’s concrete insulation factor, along with fire and smoke resistance and significant savings in insurance and maintenance, compare favorably to standard wood frame costs over time,” says St.Onge.

A study at Boston University has found ICF systems cut energy consumed by heating by 44 percent and by cooling, 32 percent.

Engineer St. Onge says ICF homes are conceptually and environmentally sound. With wood more expensive and “weaker because of new growth,” he believes tougher code requirements for seismic resistance, resulting in larger shear walls, are making wood less desirable.

Bley, whose Orinda-based Polysteel Canyon Company is building the 1-0 home, visits the construction site daily. He expects completion in October or November.

Concrete is pumped into stay-in-place foam forms to create thick insulated concrete walls that can cut heating costs by 44% and cooling by 32%. Interior and exterior walls can be finished with drywall, conventional siding or stucco.

Model of Castro Valley House

Lightweight polystyrene blocks stack quickly to create wall forms in just a few days. The system can save up to 20 trees per house and costs less than equivalent wood framing and insulation.