Public Works Director Terry Roberts was on the eighth floor of Oakland City Hall when the Loma Prieta earthquake struck with a jolt at 5:04 p.m. Oct. 17, 1989. Everything around him started to shake and shimmy. He high-tailed it down a narrow marble staircase on the side of the building until he arrived on the third-floor landing outside the City Council chamber.

As he started toward the wide curving staircase that leads to the lobby, Roberts glanced at the ornate rotunda dome and chandelier directly over his head.

"I looked up, and I could see the cracks migrating in the rotunda ceiling wall, and I thought I better move a little faster," Roberts wryly recalled nearly 20 years later.

It was the last time he or any other city employee would work inside City Hall for close to six years.

Although Oakland's magnificent, iconic City Hall showed no sign of catastrophic damage on the outside, its structural core was another story. The amount of money and effort required to fix the building was immense, and some argued it should have been torn down and replaced with a bigger, modern structure to house Oakland's seat of government — and all its workers.

But in a decision that left critics gasping and historians applauding, Oakland city leaders instead decided to save the building — even though a new one would have cost much less. They assembled architects and spent more than a year studying the damage and coming up with design alternatives to fix it. They raised the extra money to do the job right.

"There was definitely a process to decide to retrofit, and the decision didn't take too long," Roberts said. "(Then City Manager) Henry Gardner led the charge to do the evaluation whether we should keep the building or raze it. As I recall, there really wasn't a lot of attention to razing it. People really wanted to keep the building. It's a beautiful old building, an icon and identity for Oakland in many ways."

And a couple of years later, city leaders seized the opportunity to dust off a former plan to rejuvenate the somewhat blighted and listless downtown by creating a brand new City Hall municipal complex. New buildings would house city departments and staff, the Broadway and Plaza buildings would be restored, and gleaming City Hall would serve as the centerpiece.

Vision realized

Today their vision is what you see and experience when you stroll around Frank Ogawa Plaza, unmolested by cars, or enjoy a performance in the sunken outdoor amphitheater with Jack London's memorial oak tree as the backdrop.

One new office building — 250 Frank Ogawa Plaza — is located mere steps from City Hall's side entrance, separated by what used to be 15th Street before it was closed to traffic. The new building wraps around the side of the historic former Plaza Building.

The new Lionel Wilson office building at 150 Frank Ogawa Plaza flows seamlessly into the former flat iron Broadway Building, where its namesake intersects with what used to be San Pablo Avenue — until the southeastern terminus of that mighty thoroughfare was also closed to cars.

The historic Rotunda Building has been restored and is accessible from the plaza, and the new Elihu M. Harris State Building replaced the earthquake damaged City Hall West building on Clay Street.

The effect is a complete turnaround from what the area was 20 years ago, Roberts said.

"There was no plaza, it wasn't a really friendly place and the buildings around there were dilapidated," he said.

Gardner was out of town when the earthquake struck and feared what he might find on his return. When he saw Oakland City Hall still standing, he knew it was not going to fall on his watch.

"(City Manager Assistant) Ezra Rapport, (Assistant City Manager) Craig Kocian and I pushed back heavily and said City Hall is too valuable to lose," recalled Gardner, who is executive director of Association of Bay Area Government. "Ezra was a bulldog on this. He worked out how to lobby Washington, D.C., to get pro bono legal work and get state money to help with the restoration.

"It cost $85 million, and today it would cost $250 million," Gardner said. "It was well worth it. It's a jewel of a building."

'Wedding cake'

When Oakland's fifth City Hall was completed in 1914, it was the tallest building west of the Mississippi. The 97-foot-tall layered structure was designed by Palmer & Hornbostel Architects of New York in the Beaux Arts style. The facade is white granite and terra cotta, the interior white and black marble and creamy-colored imported Caen stone. The fancy design was dubbed "Mayor Mott's wedding cake" after Oakland Mayor Frank Mott married the year construction began.

It features a three-story podium supporting a slimmer, 10-story office tower. Atop the office tower rests a smaller two-story podium (floors 13 and 14), from which rises a 91-foot clock tower reached from a circular staircase inside. A three-tiered, 36-cell jail and outdoor exercise yard for the inmates is located on the 12th floor, although it hasn't been used since the 1960s.

The building was added to the National Register of Historic Places in 1983.

Had the shaking during the earthquake continued another few seconds, the clock tower likely would have collapsed, said Bruce Moen, a consultant hired by the city to help oversee the restoration project for the Public Works department.

The $85 million tab to fix and strengthen the building consisted of three jobs in one. Each section of the building was handled differently, although the work occurred simultaneously. Rather than move from the ground up, engineers began work right away on bracing the clock tower while also readying the building's foundation and structural supports. The seismic work on the middle floors followed.

Oakland City Hall had registered another first when a committee of architects and engineers, formed to determine if and how the building could be saved, came up with the idea for a base isolation system. Such a system would protect the building against large earthquakes and allow less intrusive methods to be used to seismically strengthen the building, said Alan Dreyfuss, an architect who represented the Oakland Heritage Alliance on the committee and later served as the preservation architect for the Plaza and Rotunda buildings.

Money talks

Once it was determined the base isolation method was feasible, the committee had to convince the Federal Emergency Management Agency, or FEMA, that a modern office building would not be a worthy substitute for Oakland City Hall, even if a new structure was half the cost.

"We argued that this was not just a simple office building they would be replacing, so they doubled their original estimate," recalled Dreyfuss, who now works for Wiss Janney Elstner engineers and architects. "It was a huge factor (in deciding to save City Hall). Nobody expected a bunch of fuzzy-minded preservationists to be able to talk money with FEMA, but we did."

Base isolation systems had been used in new construction and to retrofit lower-scale buildings, but Oakland's City Hall project was the first to try it in an existing, high-rise building, said Cheryl Ramirez, Oakland's facilities manager.

To accomplish the feat, the building's 90 steel structural columns were cut and raised from the concrete foundation and placed on an egg-crate shaped platform of concrete and steel. The platform rests on 113 steel-encased rubber bearings bolted to the foundation.

More than 1,000 tons of new steel was added to the columns supporting the building and an extra 800 tons was spread throughout the upper floors and clock tower.

New thick concrete sheer walls provide interior support through the sixth floor, and steel bracing was added from the seventh floor to the base of the clock tower. Aside from the basement, most of the large new structural beams were added to upper floors that are closed off to the public.

The coolest part of the seismic work is something most people would never notice unless they were told. The building is not attached to the foundation so it can move laterally 18-20 inches in an earthquake. The water and utility lines in the basement are flexible, and the stairways and railings outside the building are designed to slide over the plaza if the building moves.

"I think the biggest compliment I remember was after they finally opened it," Moen said. "People told me they were all for tearing the building down, but when they saw it they were glad they lost the battle."

Reach Cecily Burt at 510-208-6441. Check out her blog at www.ibabuzz.com/westside.

city hall retrofit
  • Cost: $85 million ($61 million from Federal Emergency Management Agency, $24 million from city.)
  • TIME: 52 months to complete from start of design
  • materials: 1,800 tons of structural steel, 4,000 cubic yards of structural concrete, 113 base isolators
  • Contractor: Turner Construction Co., San Francisco
  • Executive architect: VBN Architects, Oakland
  • Structural engineers: Forell/Elsesser, San Francisco