Keeping hospitals open after big shaker boosts Vallejo’s Earthquake Protection Systems

July 09 2018



Among the numerous cavernous buildings at the former Navy shipyard on Vallejo’s Mare Island is the home of Earthquake Protection Systems.

For more than a quarter century, it has been manufacturing special bearings that allow office buildings, bridges, elevated highways, hospitals, power plants and other critical infrastructure to ride out major earthquakes with so little damage that they’re able to continue functioning immediately after a disaster. And demand for the systems has kept EPS on the move to ever-larger facilities around the Bay Area. Now, the company is gearing up to expand yet again.

EPS’s main product are Friction Pendulum seismic isolators, invented and later patented after the founder’s postdoctoral engineering studies in the years after a devastating California earthquake.

“This is very different from the building code requirement, which only seeks to prevent collapse,” said Victor Zayas, Ph.D., P.E., president and founder of EPS, which he started in 1985. “We seek to minimize damage, so that hospitals can stay functioning, power plants can stay functioning, highways can stay open, railways can keep running.”


Helping a structure move during a temblor in a controlled, predictable way is the job of base isolators such as EPS’s friction bearing. They lessen the motion of the moving ground (substructure) that’s transferred to the building or bridge (superstructure). Other variations of base isolators include elastomeric bearings, which have layers of steel and rubber around a lead core; spring bearings with dampers; and roller bearings.

Base isolation is a technology that is commonly used for structures that are needed for postearthquake response and recovery, such as hospitals and emergency operations centers, according to James O. Malley, S.E., San Francisco-based group director and senior principal for Degenkolb Engineers.

Other applications of the technology are for special-use structures such as art museums, because of their priceless and fragile contents, and data centers, because of the value of the equipment and goal of staying in operations after a quake, Malley said. Key historical or architectural building also have been put into such isolation, namely city halls in San Francisco, Oakland and Salt Lake City.

Use of damping technology is another mechanism for improving seismic performance of structures, Malley said. Damper technology is sometimes used in conjunction with base isolation, when the site to be protected is quite large, Malley said. Types of dampers include viscous (like shock-absorbers in a car), friction, yielding (roughly like crash crumple zones in automobiles) and tuned mass.


It is not complex science, Zayas said.

"But it is somewhat detailed engineering that is different from what most know how to do,” he said. That’s because the isolator design used has to be matched with the superstructure design, else the bearing will be less than effective, he said.

“When you apply these isolators to structures built under existing code, you increase the risk of collapse by a factor of 10 to 20,” Zayas said.

In 2006, a triple Friction Pendulum isolator was developed to control the motion further. The concept for the isolator is that the building sits on a pedestal in the center of a concave metal bowl, and the specially designed friction between the pedestal moving on the sides of the bowl lessens the quake energy transferred to the superstructure.

EPS also offers a tension friction isolator, which limits up and down movement that can happen during quakes and with the sloped surfaces of the pendulum bearings.

So EPS seeks to get in at the early design stage of the project, with its team of eight engineers working with the project design and build team at the outset.


The company sees a large potential market, because many structures are designed based on the minimum compliance with the building code. The company is working with customers in 30 countries worldwide. More than two-thirds of EPS’s products are sold outside the United States.

Growth is also coming from a shift in approach by developers in the past 10 years. A selling point is that should “the big one” come, it will cost less in the long run to build a structure so that it rides out the quake, rather than code-compliant design that allows a structure to survive but require repair before it can go back into use.

“The cost is change,” Zayas said. “It’s not quantifiable in the cost of construction.”

This tectonic shift in structural design has been encountering friction from conventional approaches to distributing the forces of a temblor through a building. That’s because it’s not simply a matter of installing the isolators on a conventional design for a building.

"Isolator schemes are more effective when the structure above the isolators is inherently stiff, compared to the isolators," Malley said. "When the building is more flexible, dampers can be a more-efficient way to reduce the interstory deflections."

A recent example of this change in design approach is Apple’s new headquarters facility. It has 98 percent reliability of reducing quake damage to less than 2 percent of replacement cost. That’s one probable-loss metric used in seismic risk analysis.


Hospitals are another key example of facilities that are better left operational and not just standing after a quake. Isolators for such projects are built to 90 percent reliability to limit damage to under 2 percent.

Compare that to the current building code specification of expected damage up to 30 percent of replacement cost over the next 50 years, Zayas said.

“They’re expecting to have an earthquake over the 50-year lifetime that will render the building nonfunctional,” he said.

Hospitals have been the major source of business for EPS. Over the last 15 years, EPS has designed and fabricated its special bearings for 3 million square feet of hospitals globally. EPS has built isolators for eight hospital projects in California — namely, San Francisco General Hospital, Stanford Hospital and Mills Peninsula Hospital.

“Hospitals are the main thing that sends us globe-trotting,” Zayas said. “Because many countries have laws that require hospitals to maintain their ability to function at their maximum capacity after an earthquake.”

Zayas dived into seismic engineering in the mid-1970s, a few years after he started work as a civil engineer, working as a construction site superintendent. Those were the years after the 6.5-magnitude San Fernando earthquake in 1971, which crippled and toppled structures and started bringing seismic strengthening to the public-policy forefront.


California’s building standards for quakes have been strengthening over decades. The first design requirements in the state came with the Field Act of 1933 for schools and for hospitals built since 1973 with the Alfred E. Alquist Hospital Seismic Safety Act. The Alquist law was reinforced in 1983.

Then came the 1994 Northridge 6.7-magnitude quake in Southern California. While the new Olive View Hospital, built under Alquist standards, allowed the structure to ride through the quake unharmed, the facility had to be evacuated because sprinkler and chilled-water lines ruptured.

In response to the Northridge quake, state Senate Bill 1953 was signed, upgrading Alquist again with structural and nonstructural seismic performance categories for hospital facilities. Structural seismic performance categories (SPCs) range from 1 (risk of immediate collapse after a big quake) to 5 (operational right afterward, with very minor structural damage). General acute-care hospitals had to meet structural performance category 2 (protects “life safety”) by 2013 and will have to achieve SPC-5 by 2030.

California hospital seismic design requirements are among the most rigorous processes in the world, and that makes obtain a building permit and occupancy challenging, Malley said.

"The state standards have not, however, mandated the use of a technology such as base isolation," he said. Rather, they are called for when practical.


The World Health Organization estimates that one hospital put out of service during a natural disaster leaves as many as 200,000 without health care, and such a facility could be incapacitated during a quake even if the structure was OK, according to WHO’s hospital safety index guide for evaluators, part of the United Nations agency’s Safe Hospitals initiative.

“When we have a major earthquake today, very few structures collapse,” Zayas said. “But every single time there is a major quake, hospitals get shut down. And people in those hospitals have to be evacuated out of them. People injured in the quakes have no one to attend to them.”

Large quakes in Turkey have led to that country's adopting seismic-safety laws that call for critical facilities to be able to function at full capacity after a quake. And that has led to a number of EPS isolator sales to that country.

“The breakdown of the hospital’s functional capacity to respond to emergencies and disasters is the main cause of service interruption in hospitals in such events; only a small proportion of hospitals are put out of service because of structural damage,” the guide said. “The measures to prevent disruption of a hospital’s functionality, including critical systems, supplies, and emergency and disaster management capacities, require much less of an investment than preventing a building’s collapse.”

Those recommendations include watching how electrical wires strung between building expansion joints, so the lines aren’t disconnected as the structure moves during a quake.


Zayas earned his doctorate in structural engineering from the University of California, Berkeley, in 1980. His thesis was on better design to withstand quakes, and it chosen for the American Society of Civil Engineers Hall of Fame.

Over its 33-year history, EPS has enjoyed large growth in production, sales and workforce. The workforce has doubled every five years during that time. EPS now employs around 100, with production shifts working flexible schedules of 10- to 12-hours, keeping the cavernous shop floors humming six days a week.

With each growth spurt, the company has relocated. EPS started out in Alameda, moved to San Francisco, back to the East Bay in Emeryville then up Richmond. Then 15 years ago, EPS moved to the North Bay, settling on Mare Island.

To prepare for the next doubling of output and employees, EPS secured additional land in Solano County and threw its hat into the ring with real estate developers vying for redevelopment of 157 acres at the north end of Mare Island. EPS currently owns 340 acres in the county, including six Vallejo parcels totaling 31 acres and 305 acres of industrial land with a building recently purchased in Suisun City.

EPS’s Mare Island factory currently encompasses 500,000 square feet in three large buildings. As part of the city of Vallejo’s request for proposals to redevelop north Mare Island, EPS proposed to use 22 acres across the street from its current facility to build a six-story office building with 200,000 square feet. It would be built using its seismic bearings and a new type of reinforced concrete beams that allow large spans with few columns.

In May, the City Council opted for the north Mare Island proposal from the Nimitz Group, led by Napa Valley winemaker and soon-to-be Mare Island distiller Dave Phinney with Heitz Cellars new owner Gaylord Lawrence Jr. At the May 15 meeting, Mayor Bob Sampayan recommended the development group work with EPS on incorporating the expansion plan into redevelopment.

Phinney told the Business Journal he plans to meet with Zayas in July about whether the planned project could accommodate EPS.

Four years ago, EPS sought from the city a 22-acre carve-out from the north Mare Island property.

“I explained to the economic development manager that we would not function as a tenant,” Zayas said. So Suisun City may have to be the next destination for EPS, when the company needs to expand again, he said.

Contact Jeff Quackenbush at or 707-521-4256.