Jerome O’Connor (JO): My career consisted of two primary blocks of time:
1) 20 years with New York State Department of Transportation, where as a Bridge Management Engineer I was responsible for the safety of all existing bridges in our region (the Southern Tier of NYS).
2) 15 years with the University at Buffalo, where I was Senior Program Manager for Transportation Research, which was a federally funded program to improve the performance of bridges during earthquakes. This role evolved into leadership of the Institute of Bridge Engineering, which had a broader goal. We fostered collaboration among university professors who conduct cutting edge research, practicing engineers who applied the knowledge in real life, and the next generation of bridge engineers, students who ask fresh, insightful questions which also help to advance the state of the practice.
EOA: How and when did you first discover your interest in bridges?
JO: To be honest, I fell into it. I was in Brazil as part of a Rotary Group Study Exchange when I saw on TV news that a major interstate bridge had collapsed back home in the US. People there were shocked that this could happen in New York, the “Empire State”. That event changed things. To reduce the risk of future tragedies like the Schoharie Bridge collapse, legislators created jobs dedicated to bridge safety. My job of Bridge Management Engineer was one of them.
EOA: In your opinion, what are the essential features of a well-designed bridge?
JO: Although bridge users don’t think about them much, there are really too many features of a well-designed bridge to try to name. People may notice the beauty of a signature bridge, but I doubt they consider that a large part of the bridge (and cost) is underground. The foundation not only supports the weight of cars and trucks, but also its own weight, which consists of huge amounts of steel and concrete. Besides those “live” loads and “dead” loads, bridges need to be designed to resist rigorous shaking from wind or earthquakes that can occur. The last thing someone wants is a disaster. Not only can people die, a bridge failure severs a lifeline that is essential to the public for economic and social reasons. There is also a whole science dedicated to protecting bridge foundations from floods that can undermine these foundations.
Aside from the above, a bridge design team needs to be conscious of the communities being connected. They strive for a “context-sensitive design” that enhances the area while minimizing negative environmental impacts. For instance, it wasn’t long ago that some bridges were designed exclusively for motorized vehicles. Now, it is almost expected that a bridge needs to be wide enough to accommodate pedestrians and bicyclists. Unique features like observation decks are now incorporated into new bridges. Since bridges are built to last 75-100 years; bridge engineers need to anticipate future needs as well.
EOA: You’ve taken photos of many bridges over the years, including bridges damaged by Hurricane Katrina. Was that kind of damage predictable?
JO: Katrina’s worst damage came from tidal surges, the likes of which had only been seen in other parts of the world during a tsunami. Climate change is likely the reason for seawater coming ashore sixteen feet higher than had been recorded before. Bridge designers can’t predict what will happen in the future. Fifty years ago, when those bridges were being built, no one would have anticipated that the water would get that high.
EOA: Given a probable increase in future flooding in New Orleans and in other cities, both coastal and inland, can bridges be built or modified to sustain the inevitable 500 year deluges we’ve been experiencing?
JO: The trouble with building a bridge to handle inundation can be visualized by looking at photos of New Orleans after the floodwalls broke. Neighborhoods were flooded even though bridges in the area were “high and dry”. Eventually a bridge has to touch down on the ground where people live and work. If those areas are under water, it does not serve any purpose to have a bridge.
A bridge cannot function as a bridge if both ends of the bridge are underwater. It seems superfluous to say but the definition of a bridge is to connect two areas of refuge (i.e. dry land). One can say, just build a longer bridge, but in order for it to be useful, it eventually needs to come down to earth. Functionality and economics both come into play when trying to defy mother nature.
EOA: How do you partner with engineers in other parts of the world to assist in solving structural weaknesses or failure in bridges?
JO: Like any profession, bridge engineers and those in specialties within the field share ideas by writing professional journal articles, convening at conferences, collaborating on projects, learning from failures, etc. At the University of Buffalo, we hosted international meetings and workshops with counterparts from various states and countries. In 2016, I went to Ecuador after bridges were tested by a strong earthquake, the kind that we don’t typically get in the US. Observing how our designs perform is an opportunity to validate the results of laboratory experiments. We can always learn more.
EOA: Please give us an example of how the failure of a particular bridge impacted a community and the surrounding environment.
JO: First, the catastrophic collapse of any bridge leaves us feeling vulnerable; we grieve the dead but also think “it could have been us”. A perfect example is the 2007 failure of the I-34W truss bridge in Minneapolis. It physically came down, but it also put a dent in our nation’s psyche; it made us doubt the safety of our infrastructure. All at once, traffic on this major transportation link stopped. That meant an immediate change to people’s commuting habits, long-haul trucking, and local commerce. No one could tell how long it would last. It was cleaned up and rebuilt in a year but that kind of speed is not typical. Normally, a major project like that would take 13 years to go through the environmental review and design process. This was completed in a year under the declaration of emergency. I can’t help but wonder if funds flowed and procedural steps were slashed to erase the memory asap and patch up our psyche.
EOA: What do you find noteworthy about the River Trail Pedestrian Bridge in Redding, California?
JO: The “stress ribbon” design has a certain beauty in its simplicity. It’s ingenious in that it it’s draped between the concrete piers like a rope, instead of being stiff and flat like a beam. It’s an efficient use of materials and works well on trails like this.
EOA: And the Gothic Bridge in Central Park?
JO: This bridge obviously has a timeless beauty, but is also interesting because of what we do not see. It is made of cast iron, a material which is not used anymore because modern steels are seen as much more superior. I think of this bridge as art and its art defies its technical obsolescence.
EOA: And the Arthur Ravenel Jr. Bridge in Charleston, South Carolina?
JO: Cable-stayed bridges like this have become the bread and butter of medium-to-long span bridges. They are incredibly good at what they do and look graceful in the process.
EOA: What innovations are in the works for bridges in terms of materials and/or structural design?
JO: The emergence of advanced materials and computer analysis tools is making new things possible in the field of bridge design. Not only in terms of strength but also in terms of durability, or the ability to last a long time while being resilient to the effects of extreme forces and environmental conditions. Although Ultra-High Performance concrete (UHPC) and new types of stainless steel are exciting, the one that I see great promise in is carbon or glass fiber-reinforced polymer (FRP) composite materials. They are used for their strength and light weight in the newest jets and watercraft, but they are especially useful for bridges because the material does not rust, the curse of both steel and concrete. FRP can replace steel rebars in concrete to make it last longer. Sheets of FRP can even be applied to the outside of concrete to add strength and increase the safety factor. In New York and Puerto Rico, an entire bridge superstructure was built with FRP. These will serve for a long time, just like that composite in your tennis racquet (wink wink).
EOA: When it comes to bridges, what keeps you up at night?
JO: I sleep well at night. Bridge inspectors are working year-round to keep us all safe and are trained to close a bridge before it becomes unsafe. That said, unforeseen disasters can happen so Congress needs to put more money into maintaining our infrastructure so we can rest assured that our families are safe. Many in-service bridges were never intended to last over 50 years but are still in use. Eventually, things rust or wear out and need to be replaced. China seems to realize that good infrastructure is needed to be considered a first world economy; why don’t we?
EOA: How do engineers create bridge designs that enhance the landscapes they occupy?
JO: Two ways: They can try to get a bridge to blend in so it gets lost in the natural surroundings or they can highlight its magnificence as a work of art as a technological wonder.
EOA: In your opinion, what makes a bridge an object of beauty, a work of art?
JO: It is art if it enhances the surroundings and is a pleasure to look at. If it causes you to gaze in wonder, we’ve done a good job.
EOA: Of all the bridges in the world, which is your favorite? Why?
JO: It’s hard to argue with iconic bridges like the Golden Gate or Brooklyn Bridge. I’d pick the Brooklyn Bridge because it was built by Roebling men and women* of great vision and fortitude in a time when the nation was demonstrating its uninhibited ambition and confidence to the world.
I’d also comment that my favorites are the many being built by Bridging the Gap Africa to help people who live in a walking world to give them the ability to get food, go to school and get healthcare.
*John Roebling designed the Brooklyn Bridge. His eldest son Washington and wife Emily oversaw completion of the bridge after Roebling’s death.