In densely-populated areas throughout the United States, lengthy commutes have become a way of life. State and local officials have put off necessary repair projects of dilapidated roads and bridges that serve as vital arteries for a region’s economy.
But the Minneapolis bridge collapse in 2007, which killed 13 people, shocked a nation of motorists who traverse roadways that have long suffered from neglect and disrepair. The public scrutiny that followed the catastrophe brought forth a renewed sense of urgency to fix the nation’s aging infrastructure.
Current standards for bridge maintenance mandate inspections only every two years. But as the Minneapolis tragedy suggests, this level of frequency may not be enough to prevent bridges from succumbing to fatigue failure and eventual collapse.
At Stevens Institute of Technology, a team of civil and mechanical engineering students, under the direct supervision of Stevens faculty advisors, have figured out a way to use the vibrations caused by cars and trucks as they cross over bridges to provide an around-the-clock monitoring system.
VEHSHI—Vibration Energy Harvesting for Structural Health Instrumentation—can detect when there is a change in the consistency of the vibrations, beyond what the human eye can see during the routine two-year inspections. VEHSHI goes as far as determining defects not visible on the surface such as internal cracks, swelling or stiffness, and sends out an alert when there is a cause for alarm.
VEHSHI is the invention of Stevens seniors Mark Conticchio, Lisa Tessitore, John Murphy, Joseph Gombar, Diana Jandreski and Curtis Stecyk. They created a device that converts the mechanical energy from traffic-induced bridge vibrations into electrical energy that can be used by a structural health monitoring (SHM) instrumentation to provide continuous data about a bridge’s condition. VEHSHI can then send an alert when the received data reveals a drastic change or hazardous deviation.
In addition to the lives saved, the potential costs associated with bridge repair can be drastically reduced. According to the team behind VEHSHI, the system can potentially turn a $500 million bridge replacement into a $500,000 local repair.
For their invention, team VEHSHI garnered first place in the Elevator Plan Pitch competition at this year’s Innovation Expo, the annual competition hosted by Stevens that showcases the creativity and problem-solving capabilities of interdisciplinary student teams.
Mark Conticchio, who gave the pitch in front of a panel of distinguished judges, expressed how nervous he was when he took the stage.
“My heartbeat could have caused the bridge vibrations that we are harvesting," said Conticchio. "In the days preceding the competition, my team had forced me to give the pitch to random people off the street. The bartender thought it was a good pitch."
The team received $3,000 for its top place finish. But the real prize, says Conticchio, came from winning over the judges.
"Each one of us put our hearts and souls into this project. The fact that we were able to present it to judges who deemed us winners made it worth all the hard work.”
From the very beginning, the student team was guided by a corps of Stevens faculty advisors who formed an interdisciplinary collaboration of civil, mechanical, electrical and computer engineering knowledge.
The idea of VEHSHI emerged from a discussion that took place between Dr. Marcus Rutner and Dr. Frank Fisher in the summer of 2013. One of the areas of Dr. Rutner's research focuses on structural health monitoring (SHM), while Dr. Fisher has significant research experience in energy harvesting (EH). Their discussion centered on the wholly untapped source of energy that is structural vibrations and how to harness that energy to provide a continuous monitoring of bridges.
The opportunity to develop the idea came when they were approached by Dr. Leslie Brunell to present a topic that Stevens seniors could work on as their Senior Design Project for the 2013-14 academic year. Consequently, Dr. Rutner and Dr. Fisher identified six students they wanted to advise, and challenged them to design an EH-SHM prototype that would catch a bridge's structural defects before lives are lost and major traffic bottlenecks render roadways unusable. In developing the prototype, the students also received great support from Professor Bruce McNair in solving the electrical engineering problems involved.
“Our six-person group was able to effectively use the knowledge we gained from our education at Stevens to solve this really unique engineering problem,” Conticchio said.
A patent application has been filed on the VEHSHI prototype. In the meantime, a new senior design team will continue research on the project over the summer and beyond. Conticchio, who will return to Stevens in the fall to pursue a master’s degree in structural engineering, says he will offer support to the upcoming team.
“The more time we spend on VEHSHI, the more we can improve upon it, and the safer we can make bridges. I am also looking forward to having some new minds on the project. New minds mean new great ideas."
Meanwhile, the possibility of testing the device on an actual bridge near the Stevens Hoboken campus is building excitement.
“There has been talk of using the Pulaski Skyway for experimentation,” Conticchio revealed. “Since the deck is being replaced, we should be able to see a change in the natural frequency caused by the change in mass. This will verify our process.”
The potential commercial value of VEHSHI could be significant, but Conticchio says profit is not the focus of the project.
“Our mission is truly to make bridges safer and further the fields of civil, structural and mechanical engineering. If our product is particularly marketable, that makes me excited only because it will be placed on many bridges, making them safer.”
Moving forward, Stevens’ faculty advisors are already gaining meaningful recognition to advance the research behind VEHSHI. Just this month, Dr. Rutner was awarded one of Stevens’ Ignition Grants to set up a large-scale interdisciplinary research initiative on structural health monitoring of infrastructure systems.
“To solve the problem of aging infrastructure requires close interdisciplinary collaboration of scientists in various fields and the Department of Transportation,” explained Dr. Rutner. “The lab results of our interdisciplinary team are very promising and show what is possible through continuous structure health monitoring, and this is just the beginning of our contribution to embed resiliency and safety along with big cost reductions in America’s interdependent infrastructure.”