Nothing earth-shattering

It's no surprise Jim Roberts, a decorated Bay area bridge engineer, is this year's Roebling Medal recipient

Bridges Article August 31, 2001
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Jim Roberts was thankful to come across friendly fire in Korea back in 1952

Jim Roberts was thankful to come across friendly fire in Korea back in 1952. Or at least a form of it.

Dealing with the aftereffects of the war, the young civil engineer battled the problem of pouring concrete in the dead of winter. Heaters were his closest ally.

"They had some god awful cold winters in (Korea) and the concrete would freeze before it set up if you didn’t heat it," Roberts, who was in charge of rebuilding infrastructure for the U.S. Army, told ROADS & BRIDGES. "What would happen is you would pour a foundation wall and it would end up disintegrating. I set up tents and we used the heaters, the kind that heat up jet engines."

The unit was on guard again during the spring thaw, when frost boils began popping up on the roads. The combination of cold nights and warm days caused material just below the surface to ooze through cracks.

"We had to then go in, dig them out and fill it with better material," recalled Roberts.

When his tour was up, Roberts returned to the job of junior engineer with the California Department of Transportation (Caltrans). Fifty years later it’s safe to say his career hasn’t been camouflaged. The west coast native is a decorated veteran in the bridge engineering field, so prominent that he was recently honored with the John A. Roebling Medal for Lifetime Achievement at the International Bridge Conference in Pittsburgh. The award was presented by the Engineers’ Society of Western Pennsylvania and ROADS & BRIDGES.

"I was kinda overwhelmed when I heard I won the award," said Roberts, who is the first engineer at Caltrans inducted into the National Academy of Engineering. "I’ve received a lot of awards, but those guys represent more of the international side and the east coast. For a guy from the west to get it I really feel good about it. I’m now among a pretty illustrious group of people there."

And, as you will see, Roberts is where he belongs.

In high places

You look up at bridges; you look up to your father. Ken Roberts was a builder, and his passion was so great he left a job at a Standard Oil refinery in 1936 and moved the family to Albany, Calif., to start a business constructing houses. He caught the admiration of his oldest of six children early on.

"When he was a builder I was in high school and college and I worked with him," said Jim Roberts. "When I was in the 10th grade I made up my mind that I wanted to be a civil engineer. All I knew was that civil engineering had something to do with construction, and that was that."

With his mind set, Roberts took off for the University of California-Berkeley. His first job at Caltrans came a year later in the summer of 1951. Working part time as an assistant, Roberts’ job consisted of helping inspectors and taking samples. A worker’s strike opened the window of opportunity a little more. Due to the labor shortage Roberts was placed on a freeway surveying crew.

"In those days pavements were poured between steel forms. They set these steel pins about every 5 ft and we hit them with a sledge hammer and drilled them to grade. They set those steel forms to those pins. With the technology now they use a wire and a slipform paver."

The strike ended a few weeks later, which in turn sent Roberts back to bridge inspection. His enthusiasm for spans grew, and he went back to U of C-Berkeley in the fall more focused than ever.

"I thought bridges were real interesting," said Roberts. "You take options in civil engineering, but I went for structurals. That’s the hardest curriculum, and we did everything by hand in those days. We didn’t work with calculators until 10 years into my career with Caltrans."

Roberts worked the numbers during his first major project with Caltrans in 1952. It was a single-leaf bascule bridge between Alameda, Calif., and the Oakland Airport. Roberts remembers going down to shoot grades on the timber piling that stuck up through the concrete tremie seal.

"I did a lot of quantity calculations on that job because back then you paid structural steel by the pound. The bascule had all these odd shapes and you had to calculate the cross section and had to determine the weight for pay. That was a big job for me in those days, and it would still be a significant job now."

Back from the war

Those frost boils in Korea were nothing compared to the soft soils Roberts conquered back in California.

He spent six months as a Caltrans junior engineer before being promoted to assistant engineer. Ten years with freeway bridges led to bridge designer, senior engineer and design section supervisor positions.

Roberts’ biggest task in bridge design involved a couple of steel bridges on Highway 49 during the early 1970s.

"They were raising the dam and that was going to flood the roads, so we had to build high-level bridges," said Roberts.

The Stanislaus River Bridge at New Melones is a half-mile long steel box girder bridge standing 450 ft high. The Tuolumne River Bridge was 300 ft high.

The challenge was figuring out how to erect structures so high in the air. The crew decided to work on the ground and used falsework to jack pieces into place with large steel rods. Some of the pieces were as heavy as 1,300 tons.

"It was really spectacular when they were building it," said Roberts.

The politics of building

It was all official business for Roberts between 1972-75. State official business. As an administrative assistant for Caltrans’ director’s office, Roberts received "the best experience" of his illustrious career. He was often called upon to handle troubleshooting tasks. If a legislator called with a problem, Roberts had to investigate and offer solutions.

"When you get to the level I’m at now (director’s technical advisor) it’s 90% politics and 10% engineering," he said. "At this level you’re going to get calls from legislators and there are problems all the time. The experience of dealing with those people as an administrative assistant helped. It put me in a position to be a lot more knowledgeable as far as how things get done."

After developing a training academy for new equipment operators, called the Motorized Equipment Training Academy, Roberts’ political career continued when he left Caltrans and worked on the Sacramento Light Rail System Project in 1981. It was his first exposure to project management.

"The main thing there was change control," he said. "Every change that was made had to be documented, and if there were big changes we had to go to the board."

Money falls through cracks

Roberts was a hardball fan long before his dealings at the legislative level, and in 1989 the World Series between the San Francisco Giants and Oakland A’s brought everything to a halt in the Bay area. However, it was only temporary. Done for the day, Roberts was anxious to get home and watch his favorite team—the Giants. That’s when the San Francisco Bay Earthquake stirred up tragedy.

"One of our guys had a little television set, so we got our initial information by watching the news," said Roberts, who was chief bridge engineer for Caltrans at the time.

Watching the coverage allowed Roberts and his peers to pinpoint the collapse of the Cypress Viaduct on I-880. An emergency operations office was set up at the site, and bridge inspectors told rescue workers where they could cut to save people trapped in concrete.

Before long, 50 teams were evaluating 1,500 bridges in the region. "We inspected them within two days," said Roberts.

But somebody needed to take a hard look at the state’s funding process long before the San Francisco shake. According to Roberts, public officials knew how brittle bridges were as far back as 1971. That’s when an earthquake hit the Los Angeles area and exposed several trouble spots.

Due to lack of funding, Roberts’ crew looked at the worst cause of failure after the quake—bridge hinges. The solution was to tie them together with high-strength steel cables. The project was completed by 1989.

"There are about 350 bridges in the damage zone (of the ’89 quake) where these cables worked and the joints stayed together. If they hadn’t stayed together we would’ve dropped spans all over the freeway," said Roberts.

After hinges, the next critical area was single column supports, and the third priority after the 1971 earthquake was mobile column supports. Money, however, wasn’t available.

Roberts and others faced criticism from high-ranking officials after the San Francisco event. Most thought crews should have taken sections and addressed all three mending methods.

"We feel what we did was right, and I would do it again," said Roberts. "We were getting $4 million a year and used every bit of it. The column support estimates were made at $6 billion and nobody wanted to touch it, and I told them that that was unacceptable. It didn’t happen until we had the disaster, and that’s a sad commentary on our times, but it’s true everywhere."

In 1990 funding went from $4 million to $300 million.

Put on a jacket

Roberts is a scholar when it comes to earthquake strengthening and is known as the father of California’s bridge seismic retrofit program.

He helped promote the use of steel jackets for aging bridge columns. The procedure involved the applications of 1/2-in. steel shells, some 10 ft in diam. Today, composite materials have replaced steel as the product of choice.

Another discovery involved tie bars. Bridges designed before 1971 had 1/2-in. tie bars wrapped around columns at 12-in. spacings.

"That was way inadequate in keeping that concrete pour from cracking," said Roberts.

As a preventative measure all columns are now designed with a continuous wrap of 3/4-in. steel with about 3-in. spacing. Roberts claims the improvement creates "eight times the confinement."

Under Roberts’ leadership Caltrans also has developed design techniques where they can actually force the location of first distress.

"It’s called a plastic hinge. You can see distress—usually at the top of the column—so you don’t have to go in and excavate to look at the footing. Before it would fail below the ground. Now we can control the location of that first failure."

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