Carbon fiber road bridge was selected as one of the 16 most valuable transportation projects in the United States

Carbon fiber road bridge was selected as 

one of the 16 most valuable transportation projects in the United States

For decades, the Michigan Department of Transportation (MDOT) and local universities have been committed to using new material technology to double the service life of highway bridges. The project is recognized as one of the 16 most valuable transportation research projects in the United States.

The Lawrence Institute of Technology (LTU) in Southfield, Michigan, used carbon fiber reinforced composite cables to replace steel bars as reinforcements for concrete bridges and conducted related research. This project was named the 16 most valuable projects in 2020 by the National Highway and Transportation Officials Association (Sweet 16). The project was launched in 1988 and was carried out by Nabil Grace, Dean of MDOT and LTU School of Engineering. In 2001, the first carbon fiber reinforced bridge in the United States was built on Bridge Street in Southfield. After that, Michigan built more than a dozen carbon fiber reinforced bridges including I-75, Gratiot Avenue and Eight Mile Avenue.

 As a conventional material for highway bridge reinforcement and prestressing of concrete, steel is prone to corrosion and deterioration when exposed to extreme temperatures, humidity and deicing chemicals. The tensile strength of carbon fiber cable is equivalent to that of steel. Although its upfront cost may be higher, it is more resistant to corrosion and requires less maintenance during service.

"In the field of bridges, CFRP performs well, but the understanding of its long-term durability characteristics is not deep," said Matthew Chynoweth, chief engineer and director of bridge structure bureau of MDOT.This research is carried out at LTU's Innovative Materials Research and Development Center. In the past four years, carbon fiber components have undergone 300 cold and heat cycles with simultaneous flame and load, severe weather and various other performance tests. Even under test conditions that simulate the severe weather in Michigan, CFRP performed well, and humidity, rain, freezing rain and extreme temperature changes failed to affect its strength and other mechanical properties. Test results show that the current performance indicators accepted in the industry are too conservative and can be updated.

The goal of the project is to develop a bridge with a service life of more than 100 years.

The project also provides guidelines, suggestions and design examples for engineers and designers. At the same time, Tokyo Rope, a Japanese CFRP supplier, set up a factory in Canton Town. Because the sensor is implanted in the carbon fiber bridge in advance, the sensor can monitor the displacement and stress status of the bridge in real time.