November 1, 2012 By Noelle Knell
“Currently there are multiple traffic data sets in any given city,” said Belcher. The state and city, as well as transit and safety organizations, collect data for different reasons and usually don’t share it, he added.
Many jurisdictions publishing open data today are finding their greatest successes in public transit, as private software developers are creating interesting mashups that capitalize on multiple data sets, often from different agencies. Belcher argued that aggregating this data en masse can reduce the need for additional infrastructure construction and drive additional innovation not yet imagined.
“As we go forward, cities, regions, states are going to scrape all of that data, normalize it, and use it for broad data analytics,” he said, “which will allow regions and states to optimize their transportation systems across modes, across regions and across cities.”
According to the FHWA, roughly 25 percent of the 600,000 bridges in the U.S. need to be replaced or repaired. The I-35W bridge collapse is widely cited as motivation by engineers working on wireless sensing technology that can help detect structural shortcomings in time to make needed repairs.
A Better Way to Build Bridges? Experts say upgrading U.S. infrastructure requires doubling the current federal funding level over the next decade to $5.5 trillion. While few would claim that improving U.S. infrastructure isn’t a staggeringly expensive proposition, evidence exists that upfront investments in new approaches can reap long-term benefits. Blaine Leonard, former ASCE president who currently is the intelligent transportation systems program manager for the Utah Transportation Department, said his state employs a bridge replacement strategy that’s catching on. Called accelerated bridge construction, the strategy minimizes traffic impacts for citizens from long-term bridge construction projects. The accelerated process carries out as much physical construction as possible offsite — in Utah’s case, on land adjacent to the current bridge. Full demolition of the old bridge and replacement with the new structure takes place during one weekend. While more expensive and a bit risky when first attempted, it can now be done more cheaply than the traditional method and minimizes impacts to commuters. Photo courtesy of Shutterstock.com |
“Due to the advances in sensor technology, communication and more important, the miniaturization of all these electronics, it has become very practical,” he explained. “We can develop the systems to monitor bridge health in real time.”
Several different kinds of sensors are currently being piloted. Accelerometers capture bridge vibrations generated by vehicle traffic, but offer little information on localized damage, Yuan said. Piezoelectric sensors capture acoustic emission signals, offering a glimpse into potential structural vulnerabilities. Much of Yuan’s research is focused on harvesting sufficient energy over low frequency ranges to power the sensors and their wireless data transmissions back to central computers to enable effective analysis.
“I believe that 25 years from now, almost every bridge, existing or new, can use a wireless sensor system in a very economical way,” Yuan said. While sensors can be utilized on existing structures, incorporating them into the planning process for new bridges can potentially save money. More effective monitoring, he believes, can ease certain construction requirements and perhaps reduce visual inspection needs.
Experts agree that an influx of funding for transportation infrastructure in the next decade is unlikely. Planners now well versed in working with tight budgets are increasingly looking at how to make the most of their current transportation resources. Many jurisdictions are piloting solutions that are expected to see widespread adoption in coming years.
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The highest value use for "monitoring" bridge health is to support a decision that safely extends the life span of a bridge that was classified "deficient" or "posted" after a visual inspection. The FHWA discounted the efficacy of visual inspection 11 years ago in a comprehensive report; concluding it was "subjective" and "not sufficiently reliable" to make optimal financial decisions involving bridge repair or replacement. Given our current national and local financial constraints, monitoring technologies can provide essential information to objectively assess bridge condition and defer unnecessary repairs or replacements, while not compromising user safety. Monitoring technologies are commercially available TODAY and don't need more research as this article subtly suggests. The data needed is well known and the analytical techniques are all proven and cost effective. What is missing is the willingness of State DOTs to employ this technology when a bridge is first classified as "deficient", both for National Highway System bridges and locally owned bridges. My firm and others are available and willing to help bridge owners safely defer billions of dollars in capital expense, knowing that deferred expenses can be used for higher priority projects. It's all about using precious taxpayer funds in the most effective manner. Again, the time to deploy these technologies is NOW; more research is NOT necessary.