The research keeps coming. One notable project is occurring on the campus of University of Nevada-Reno (UNR). Researchers are testing the impact of composites in bridge structures under earthquake conditions.
Saiid Saiidi, engineering professor at UNR, says this kind of testing helps researchers understand how the entire system works, which adds to its credibility. He used glass fiber composite columns filled with a carbon tube, and simulated intense back-and-forth movement on the structure to assess how the materials would hold up after a tremor.
The team noticed immediately that the materials did not suffer any external stress damage. “The composites stayed strong after the damage, so you would not have to shut down the bridge,” says Saiidi. The biggest factor, which will take time to measure effectively, is the state of the internal stress damage. Seeing the specific results of those internal stresses from an earthquake could be a major way to make engineers comfortable using composites. “There is no database to tell them that it looks good on the inside. Time and data are needed, especially as engineers’ feelings are evolving and improving and the cost of composites has also become competitive,” says Saiidi.
Saiidi thinks discovering this information could benefit the industry. “We’ve been using concrete and steel for decades, so the comfort level is high. Composites are relatively new, and because of the large liability involved in projects like bridges, engineers are very cautious and need more time to feel comfortable. On top of the work done by ISIS Canada, a network created to provide civil engineers with better ways to build, repair and monitor structures using high-strength FRPs, this will aid in increasing the legitimacy of composites,” he says.
#5: The Near-Future Holds Promise
Despite these developments, composites remain at a disadvantage because they don’t have an established design standard. Established standards for traditional materials have been in place for decades, which makes it tough for composites to compete.
“The standards are important, because they’re what an engineer goes to as a means of designing structures,” says Dan Witcher of Strongwell. And according to him, these complete FRP standards are 90 percent close to completion.
Witcher is the chairman of a committee working with the American Society for Civil Engineers (ASCE) on this issue. FRP manufacturers have raised funds and pushed for this change for several years, but it wasn’t until 2007 that progress started to occur. The industry contracted with ASCE to develop a pre-standard that would cover LRFD (load resistant factor design) design of bridge structures using pultruded FRP shapes.