America’s bridges are aging and in dire need of repair or replacement. Most U.S. bridges were built for a 50-year design life, and the average age of bridges nationwide is about 45 years.
More concerning is that drivers make about 200 million trips daily across these substandard bridges. Conventional methods are inadequate to repair or replace these substandard bridges. Traffic jams already are alarming and additional construction activities are bound to significantly disrupt the traffic flow, reduce mobility and, more importantly, create construction zones that are a magnet for accidents, fatalities and injuries.
Fortunately, there is a solution –a new technique known as accelerated bridge construction (ABC), which allows for replacement and retrofitting of deficient bridges in a timely, safe and cost-effective manner by conducting more than 90 percent of the work offsite.
“Dealing with the problem of deficient bridges is a major task. The level of the funding required to address all these problems is just not there,” says Atorod Azizinamini, director of FIU’s Accelerated Bridge Construction Transportation Center (ABC-UTC). FIU’s bridge engineering program is one of the university’s five preeminent programs focused on advancing solutions to society’s most pressing problems.
“As a result, we are trying to develop the latest technologies, methods, solutions and products that effectively address all these substandard bridges, but at the same time in a very economical manner,” adds Azizinamini, who is also the chair of the Department of Civil & Environmental Engineering within the College of Engineering & Computing.
The implications of our failing infrastructure could be deadly and date back generations. In 1967, the Silver Point Spring Bridge in West Virginia collapsed, killing 40 people. In October of this year, sections of a sidewalk and railing in North Palm Beach, Florida, collapsed into the intracoastal waterway. No one was injured, but both vehicular and boat traffic along and under U.S. Highway 1 were halted or rerouted.
Though the Silver Point Spring Bridge collapse resulted in Congress requiring that every bridge in the United States be inspected once every two years, about a quarter of the 607,000 U.S. bridges, some 145,000 bridges, remain in need of repair or replacement, Azizinamini says.
FIU News recently sat down with Azizinamini to learn more about fixing the nation’s dilapidated bridges.
The major problem is that we have so many substandard bridges that the public passes over on a daily basis. We’ve had some unfortunate accidents in recent years, one of them being August 1, 2007, on the I-35 bridge in Minnesota; more than 140 people were injured and 13 people lost their lives and that shouldn’t happen.
If we know the potential dangers, why aren’t aging bridges being fixed?
The reason that accidents happen, like that in Minnesota, was not because we didn’t know something that we should. The reason was that we just didn’t have the money and the funds to replace that particular bridge. The warning signs were there and the Minnesota Department of Transportation knew the problem, but the resources to address the problem were not available so that bridge was kept basically in operation.
Cost is indeed a prohibitive factor. And I’m afraid that’s only the tip of the iceberg because unfortunately more of those accidents will happen if we don’t address these problems, not only with the bridges but other infrastructures that are critical.
On a daily basis as a nation, we are falling behind. Infrastructure is a major contributor to the economy of this country. If you want to replace them, that causes traffic congestion. The traffic congestion, according to the latest reports, is costing the society $160 billion a year, that’s almost more than $440 million per day. So as costly as infrastructure repair may be, we can’t afford really to go about business as usual and ignore these concerns.
What’s the solution then? Accelerated bridge construction (ABC) is the most viable solution. Today, to build bridges, we close the roads for a period of months or one year. When you close the road for construction, what do you do? You put these ugly orange cones that everybody hates to see, and you cut the traffic lanes from two to one, so you create traffic jams. These construction zones are also a magnet for accidents. Lots of accidents take place, accidents involving construction workers because drivers are distracted and do not take the precautions they should.
With ABC, the total time that it takes to construct a bridge doesn’t change, pretty much, it’s about the same, but the major difference is that you do almost 95 percent, sometimes 99 percent, of the work offsite. You build a big component, or the whole bridge offsite, and then over a matter of hours, or in the matter of a day, you bring it, and assemble and install it on location. ABC is eliminating the onsite construction activities- you are doing the construction somewhere else. The public impact then is far less – instead of one year to repair or replace a bridge, it could be one or two days. As a result, you’re reducing the probability of accidents onsite and there are significant cost savings with ABC methods.
The repair, and replacement, of American bridges as well as advancements in bridge engineering will be the focus of the 2017 National Accelerated Bridge Construction Conference to be held in Miami, FL, Dec. 6-8. The conference is presented by FIU’s Department of Civil and Environmental Engineering and the university’s Accelerated Bridge Construction University Transportation Center (ABC-UTC).
Since the launch of the conference in 2014, the event has featured 400 technical and research presentations and has attracted more than 1,300 engineers, administrators and construction-company officials from all across the United States, and abroad, to discuss technological advancements and the benefits of ABC.
For more information or to register for the conference, visit abc-utc.fiu.eud/conference.
– Garth Headley contributed to this story.