Caltrans’ Michael Johnson oversees California’s efforts to keep its bridge infrastructure safe, reliable and resilient to climate change.
If you’ve never worried about the safety of the bridges you cross every day on your way to work or the grocery store, you can thank Michael Johnson and his team at California’s Department of Transportation (Caltrans).
Keeping Travelers Safe
As the agency’s State Asset Management Engineer and Acting State Bridge Maintenance Engineer, Johnson oversees and manages Caltrans’ $4.5 billion annual investment in highway and bridge infrastructure improvements. As part of the latter job, he leads a team of 240 employees responsible for inspecting and ensuring the safety of more than 42,000 bridges, tunnels, overhead signs and pedestrian overpasses owned by the State of California or its local government agencies.
“Every few days our bridge infrastructure experiences some sort of accident—a truck crashing into a bridge, a ship hitting a bridge, a fire, a flood or some other sort of damage that requires a response from my team,” explains Johnson.
And every situation draws uniquely on his team’s engineering skills, structural analysis tools and creativity to repair, renovate or otherwise restore each bridge to its safest condition for California travelers, he adds.
Learning by Doing
To be sure, Johnson has had a front seat on repair and renovation projects his entire life. He grew up in Novato, Calif., a San Francisco suburb, in what seemed like an active construction site. His dad, a San Francisco police officer who Johnson describes as “handy,” delighted in remodeling the family home, no matter where they lived.
“We were always adding on, expanding or otherwise reconfiguring the homes we lived in,” he recalls. “And I helped a lot on these projects. In fact, being exposed to construction, to building, and mechanical design really fed my curiosity about how things work.”
Keeping It Civil
That curiosity also helped Johnson shape a career path that he describes today as “somewhat circuitous.” In high school, he took a class in architectural drawing.
“From my early exposure to home construction projects, learning how to draft and design a house seemed like a neat thing to do,” he offers. “And after winning a school award for one of my home designs, I was convinced, at age 17, that I was going to be an architect.”
Unfortunately, the only schools in California offering architectural programs at the time – the University of California, Berkeley and Cal Poly San Luis Obispo—had other plans. They invited him to join their civil engineering, but not their architectural programs.
In the end, Johnson followed his friends and his instincts — civil engineering seemed “close” to architecture—to Sacramento State where he earned both a bachelor’s degree in civil engineering and later, a master’s degree in civil engineering with a concentration in structural analysis.
After graduating college, Johnson went to work for Caltrans … and he’s been there ever since.
In his early work assignments, he learned the finer points of bridge infrastructure—design, construction and maintenance. From there, Johnson progressed to becoming a bridge inspector, and eventually co-authored the AASHTO Bridge Element Inspection Guide Manual, a publication still used widely by bridge professionals nationwide.
Staying Ahead of Reality
Today, Johnson’s infrastructure team performs about 1,000 inspections per month, primarily bridges but also tunnels and overhead sign structures. Most California bridges require inspection at least once every two years. The goal is to stay ahead of the relentless wear and tear caused by traffic accidents and natural disasters, and the relentless exposure to sun, rain, snow, freezing and thawing.
“We have many bridges and each one requires somewhat unique attention,” explains Johnson. “Some require repair and improvement while others simply need preservation treatments to extend their life. We also need to reduce their vulnerabilities to things like seismic events, flooding or even now, sea level rise.”
Fortunately, technological improvements have made Caltrans’ job easier. Bridges that were originally constructed from wood, for example, are now built almost exclusively from steel-reinforced concrete making them essentially invulnerable to natural disasters such as wildfires.
“We’ve had cases where reinforced concrete bridges have stood in the middle of a forest fire for weeks on end and still been okay,” says Johnson. “Steel bridges also do pretty well in fire situations, except their paint usually gets burned off and they have to be repainted, which can be expensive.”
Increasingly, he adds, Caltrans is using a polyester concrete material on its bridge decks. This material, which can last up to 30 years, helps offset the relentless wear on California bridges from high traffic volumes while reducing the agency’s long-term costs of ownership.
Putting Travelers First
For all the effort that Johnson’s team puts into ensuring the safety and resilience of the State’s bridge infrastructure, he points out, their work is largely invisible to travelers.
“Most people don’t appreciate the lengths that Caltrans goes to avoid inconveniencing the public when we do our work,” he suggests. “Most of our bridge inspections are done late at night (9 or 10 p.m.) or very early in the morning (3 or 4 a.m.) when traffic is lightest.
We also try to do most of our repair work when people are home sleeping, so when they get up, the roads are open again and they don’t realize what all took place the night before.”
Preparing for Earthquakes
And while Caltrans can repair and refurbish roads and bridges on their own schedule, they still have no control over another major disruptive force to California’s bridge infrastructure: earthquakes. Fortunately, advised Johnson, Caltrans is a world leader in the seismic design and retrofit of bridges. The agency has done extensive studies of seismicity and the response of its bridges to ground motion.
“We’ve developed software that allows us to quickly understand where an earthquake occurred, how many bridges may have been affected, and whether those bridges were damaged based on the amount of ground acceleration they experienced,” he says.
Climate change is also a growing threat to the State’s highway and bridge infrastructure.
“Here in California, drought and wildfires are becoming more and more frequent,” observes Johnson. “When we have big fires, trees and vegetation burn, hillsides become prone to landslides or mudslides. We’ve had cases where entire highways have been buried by hillsides that were burned in a fire one or two seasons before.”
He’s also concerned about the impact of sea level rise along California’s coast.
"We’re seeing an increasing number of cases of low-lying bridges being inundated by seawater, which obviously hinders highway operations,” he says. “We’re also seeing more and more coastal erosion caused by wave action.”
To that end, he adds, Caltrans is now building coastal highways and bridges farther inland, or at elevations that can accommodate sea level predictions for 2100.
Work schedule aside, Johnson is mindful of the huge responsibility he and his colleagues bear to be good stewards of the $4.5 billion budget allocated to identifying, prioritizing and completing California’s most pressing highway infrastructure projects. And he treasures the opportunity to bring his family-taught ethics of hard work and resourcefulness to work every day.
“I love the challenge of the projects that come at me in my job, but you know, it’s really much more than that,” explained Johnson. “On the one hand, bridges are civil infrastructure, a way to get across a river or depression in the landscape. But they are also the way that families go to work, go to school and come together at the end of the day. In my experience, people are very passionate about bridges because those bridges stitch together the fabric of local communities. I love knowing that our work helps bring people together.”
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