Federal, state, and local officials gathered at Lawrence Technological University’s Center for Innovative Materials Research (CIMR) to witness a first test of a bridge reinforced with 0.7-inch diameter carbon fiber reinforced polymer (CFRP) strands instead of steel bars, producing longer-lasting bridges that cost less to maintain.
The 41-foot section of the bridge that was tested finally collapsed after more than 180,000 pounds of pressure were applied in a narrow section of the bridge. The bridge bowed downwards nearly two feet before collapsing. Nabil Grace, dean of the LTU college of engineering says of the test: “This is good news.”
The situation simulated in the test would never occur in real life as that much weight could not be concentrated in such a small area, according to Matt Chynoweth, chief bridge engineer and director the bureau of bridges at the Michigan Department of Transportation. The test demonstrated how much reserve strength is available using CFRP strands.
“Our successful partnership with Lawrence Technological University has produced a number of innovations, and advances in longer-lasting bridges is among the highlights,” says Paul C. Ajegba, director of transportation at MDOT, who attended the test.
LTU and MDOT have been working on CFRP bridges for more than 20 years. The goal of the project is to create bridges that last 100 years, at least 25 years longer than the current state-of-the-art technology provides while also cutting maintenance and saving taxpayers money in the long run.
Based on the results of the bridge model test, it Is expected that the 0.7-inch CGRP strand design guidelines will be finalized and added to the existing MDOT design guidelines for use in the deployment of CFRP bridges.
“The MDOT-LTU collaboration, with the assistance of our federal partners over the last 20 years, has established Michigan as a leader in advanced bridge infrastructure using innovative materials that can yield a remarkable 100-year service life,” says Virinder Moudgil, president of Lawrence Tech.
The first two projects using the technology are proposed by MDOT, the lead in the Department of Transportation Pooled Funds Project, would be over I-94 in Detroit. This test is also a precursor to advancing the development, testing, and deployment of the 0.7-inch CFRP pretensioned strands and full integration and deployment of ultra-high-performance concrete (UHPC) in the next few years, a substance that has been demonstrated to have five times the strength of current concrete.
Attending Monday’s test were U.S. Rep. Brenda Lawrence, D-Southfield, Michigan Department of Transportation Director Paul C. Ajegba, and Oakland County Executive Dave Coulter.