Dr. Christopher Higgins, Professor at Oregon State University Recipient of 2015 Titanium Applications Development Award
Dr. Higgins, working with Perryman Co., Houston, PA, was cited for his role in developing a novel titanium application for repairing highway infrastructure. Higgins will be presented with the prestigious award at the TITANIUM 2015 Conference on Tuesday, October 6th in Orlando, Florida.
The Oregon Department of Transportation (ODOT), Salem, OR, selected a repair concept by Higgins—a titanium “staple” to reinforce fractures in the reinforced concrete—which was deployed by ODOT on the Mosier Bridge, an “overcrossing” of Interstate 84, which is a major east/west corridor for the state. Higgins designed the idea of the staple and the requirement of a surface treatment that would allow titanium alloy bars to be used to strengthen concrete bridges. Perryman Co. manufactured the titanium staples and developed the methods to produce the surface treatment. Oregon State tested alternatives and selected the final pattern.
Frank Perryman, president and chief executive officer of Perryman Co., said repair work, using the titanium staples, was completed in June 2014. As a result, this is believed be the first titanium-reinforced concrete bridge in the world.
Mosier Bridge, located above milepost 69.65 of Interstate 84, is a four-span reinforced concrete, deck-girder bridge, which originally was built in 1950 and widened in 1959. According to information posted on the Oregon state government website, a routine bridge inspection in May 2013 identified significant cracking in the bridge’s girders and determined a number of crossbeams were “structurally deficient.”
After making these observations, ODOT contacted Higgins. He reviewed the plans and independently determined “that the bridge members had little reserve strength and the loads on it were close to the calculated collapse load. This was verified by tests of full-size replicas of the bridge girders in the lab. I recommended they close, post and/or shore it up until it could be fixed.”
By coincidence, Higgins said that, at the time, he and the students in his laboratory were doing research work on using “non-traditional metallics” to remedy deteriorating infrastructure. Going through his network of business associates, Higgins was introduced to Warren George, an Oregon-based Perryman Company engineer.
Based on research at Oregon State, ODOT called for the use of titanium staples to fortify the bridge. Higgins explained that carbon fiber typically is the material of choice for such repair work. However, he gave credit to ODOT for not being intimidated to consider an innovative alternative. The titanium approach prevailed and, in addition to providing design and structural advantages to carbon fiber, it proved to offer an overall cost savings of 30 percent.
The Oregon government website indicated that repairing this bridge was a “high priority for ODOT” because the load restrictions impacted local businesses in the area. As a result, “strengthening of the bridge was put on an accelerated schedule.” Higgins praised ODOT for recognizing the concept of a “total life-cycle cost system approach” for the bridge project. Jim Perryman Sr., the founder of the company, “took this bridge project to heart and was the driving force,” according to his son, Frank Perryman, the company president and chief executive officer. “This was truly a team approach to achieve the desired goal, having our people work with Professor Higgins and the ODOT. It was an exciting process for us.”
Frank Perryman described the titanium staples as “near-surface mount” components that reinforce the concrete structure. The staples were fabricated at different lengths, depending on distance needed to span the beams. Each staple, a titanium aerospace-grade 6/4 alloy, was designed with surface grooves along the length of each staple to enhance their “holding characteristics.” He pointed out that one important design advantage for the titanium staples, compared with carbon fiber bars, was the ability to incorporate L-shape end hooks, which anchored the staples in the reinforced concrete.
When it comes to infrastructure, cost must be weighed against public safety. Higgins said that cost is always an issue, but the hardest part is getting past the “too-expensive” first reaction when it comes to specifying a material like titanium. “You’re not buying a construction material by the pound; you’re buying it by its performance and long-term, life-cycle costs,” he said. “There are lots of needs when it comes to infrastructure, but there are limited dollars to pay for projects. My discipline (civil engineering) is a very conservative field. If cost is a critical issue, then we must spend wisely with the money that is available. This means that instead of replacing and rebuilding a bridge, we’ll need to find ways to better maintain and strengthen existing structures.”
Given its properties of strength, ductility and the ability to be impervious to weather and corrosion from roadways that are salted during winter months, Higgins said cost issues actually could favor titanium for future infrastructure applications. He said there are many ways to measure cost, such as the inconvenience and drop in productivity from closing an important road system, as well as and the time and effort it take to complete the repair work.