Ann Arbor Business Review
October 11, 2007
The statistics are unchanged in 20 years: about a quarter of the 600,000 bridges in the United States are in need of replacement. Yet built of better materials, bridges could last as long as 100 years, according to Lawrence Technological University researcher Dr. Nabil Grace. He is developing various uses - including bridge construction - for carbon fiber reinforced polymers.
"Steel rusts - pretty quickly actually - when it's exposed to water and salt," Grace said.
By replacing steel and concrete with CFRP and concrete in bridge construction, bridges could remain intact much longer, possibly twice as long, he said.
Carbon fiber has many applications - in industries as wide-ranging as automotive and nautical, aeronautical, defense, as well as in civil infrastructure uses such as bridges.
It also is available in varying grades of strength. It comes in a range of costs, anywhere from $10 a pound to $60 a pound. The less-expensive variety can be used for items such as bicycles, golf clubs and fishing rods. The most expensive is used in aerospace applications and structures including bridges.
The fibers look like hair but are much stronger, Grace said. When mixed with an epoxy and processed, the resulting material is very strong, though sometimes brittle. The reinforcing bars made with the fibers can be 5 millimeters in diameter to 40 millimeters.
"If you take a look at bridge construction, we use steel rods, or what's called rebar. After 15 years, because of the harsh environment, the rebar experiences significant corrosion and the concrete crumbles," Grace said. "If we replace that with something that's not going to corrode, if you put it in the bridge, crumbling problems disappear."
And CFRP is 10 times as strong as steel, but only one-fifth as heavy, he added.
It does cost more - as much as five times as much as steel. But when one considers the life cost cycle of a bridge from construction to maintenance, repair and the cost to commuters when repairs force detours, the bridge made with carbon polymers winds up in the long run costing far less, Grace said.
And then there are the costs that can't be calculated, Grace added, alluding to the deadly highway bridge collapse in Minnesota in early August.
"The United States used to have the best infrastructure in the world. For something like what happened in Minneapolis to happen in the U.S. is really not good - it says we are way behind. We need to be more innovative and look for materials that last longer and wear better," Grace said.
The Michigan Economic Development Corp. has called for proposals on building bridges that could last 100 years, Grace said.
Grace and Lawrence Tech researchers teamed with the Michigan Department of Transportation to submit a proposal, and the MEDC awarded $900,000 for researching carbon polymers for use in the construction of box beam bridges, Grace said.
"We are the only school in Michigan that's doing this, the testing and deployment of new materials in highway bridges," Grace added.
The U.S. Department of Transportation awarded $1.1 million for research for a five-year research program for the carbon polymers, and the National Science Foundation awarded Grace and his team a $500,000 grant to study environmental effects on the polymers.
Southfield, Mich. - Nabil Grace has been named the first university distinguished professor at Lawrence Technological University by the Board of Trustees.
Grace is chair of the Civil Engineering Department and director of the Center for Innovative Materials Research (CIMR) at Lawrence Tech.
The university distinguished professor is the highest faculty rank at Lawrence Tech. It is awarded for exemplary achievements that have brought special distinction to the university. A university distinguished professor must demonstrate excellent teaching skills in addition to widely recognized accomplishments and extensive publications.
Grace is best known for his research on bridge design methods that take advantage of carbon-fiber reinforced polymers (CFRPs). Unlike steel that is typically used for structural reinforcement, CFRPs won't deteriorate quickly when exposed to water, salt, and chemicals.
He has a patent for hybrid ductile fabric, an unusual combination of carbon and glass fibers that can be used to reinvorces bridges and buildings.
Under Grace’s leadership, Lawrence Tech developed its Center for Innovative Materials Research with the help of a five-year, $11 million cooperative agreement involving both the Army Research Laboratory and the U.S. Army Tank Automotive Research Development and Engineering Center (TARDEC). The $3.2 million research facility opened this year.
Grace also is the principal investigator for a three-year, $899,996 grant awarded in September by Michigan’s 21st Century Jobs Fund to develop, implement and commercialize new materials and engineering practices that are expected to double the lifespan of highway bridges that use box-beam construction.
“Dr. Grace’s innovative research in carbon-fiber, reinforced concrete designs has received international recognition. His contributions will increase the sustainability of our nation’s highway infrastructure,” Lawrence Tech President Lewis N. Walker said. “He is a bold leader who has found creative ways to expand the civil engineering program at Lawrence Tech.”
Grace did his undergraduate work at the University of Cairo in Egypt and earned a master’s degree and Ph.D. in civil engineering from the University of Windsor. He joined the Lawrence Tech faculty in 1988.
Lawrence Technological University, www.ltu.edu, offers more than 60 undergraduate, master’s, and doctoral degree programs in Colleges of Architecture and Design, Arts and Sciences, Engineering, and Management. Founded in 1932, the 5,000-student, private university pioneered evening classes nearly 75 years ago, and today has a growing number of weekend and online programs. Lawrence Tech’s 125-acre campus is in Southfield, with education centers in Livonia, Clinton Township, Traverse City, and Petoskey. Lawrence Tech also offers programs with partner universities in Canada, Mexico, Europe, and Asia.
Lawrence Technological University (LTU), and Hubbell, Roth & Clark Inc. Consulting Engineers (HRC), recently received state and national awards for their engineering achievements related to the Bridge Street Bridge project in Southfield. (Editor's note: see separate photo attachment; caption at end of release.)
The American Consulting Engineers Council (ACEC) of Michigan, and the Michigan Society of Professional Engineers awarded the engineering design and research team the Eminent Conceptor Award the highest award for engineering excellence for outstanding achievement for an engineering or surveying project.
At the ACEC Engineering Excellence Awards Gala in Washington D.C., Lawrence Tech President Charles M. Chambers accepted the ACEC Honor Award, along with Southfield Mayor Brenda Lawrence and HRC Vice President George Hubbell. The annual ACEC Engineering Excellence design competition celebrates the greatest engineering achievements of the year that demonstrate the highest degree of merit and ingenuity.
Both awards recognized HRC's outstanding engineering work and the pioneering efforts of Nabil Grace, professor and chair of civil engineering at Lawrence Tech. Over a 10-year period, Grace developed a revolutionary concept using carbon fiber reinforced polymers (CFRP) in prestressed concrete highway bridges. Grace and a team of Lawrence Tech students performed extensive laboratory testing, funded by the National Science Foundation and others, to prove the strength of the innovative CFRP design. These government-funded investigations were conducted in the Structural Testing Center (STC) at Lawrence Tech. The state-of-the-art STC is one of the largest such testing facilities in Michigan.
As a result of Grace's research, the University collaborated with HRC and the City of Southfield to replace the outbound lane of the failing Bridge St. Bridge as a full-scale national demonstration project using the new technology. Computer sensors placed in the new Bridge St. Bridge allow the design team and the City to monitor the bridge's performance over time, and compare it to the performance of the conventional steel-reinforced span that carries in-bound traffic. The $8 million project was built with funding from the Federal Highway Administration and the City of Southfield.
CFRP products are made from very thin fibers of carbon, about the diameter of a human hair, said Grace. These long fibers are woven together and encased in epoxy to optimize bridge durability. The greatest advantage of the CFRP concept over conventional steel is that it is much less susceptible to corrosion, he explained. Corrosion from deicing chemicals is the leading cause for concrete deck and bridge beam repair and replacement. Therefore, the on-going research will demonstrate the long-term economic benefits of CFRP over conventional steel reinforced bridges.
This is the first completed multi-span concrete highway bridge in the world to be prestressed and reinforced with CFRP tendons and rods instead of metal cables. There are no existing standards developed by private, state or government agencies in the U.S.. Therefore Lawrence Tech, HRC, the City of Southfield, and Japanese manufacturing firms worked together to research the design, coordinate material testing and determine design criteria and construction standards for this unique CFRP bridge design concept.
The Bridge Street Bridge serves as the sole access to over 50 businesses within the Bridge Street Industrial Park, a major artery to Southfield's vital industrial traffic. Using the CFRP design concept, the City has solved a critical infrastructure problem with a unique and first-of-its kind bridge that may very well represent the future of America's highway bridge construction technology.
Other team members on the project included: the University of Windsor; Construction Technology Laboratories, Skokie, Ill.; Prestressed Systems Inc., Windsor Ontario; Mitsui & Co. (USA) Inc., Cleveland; Sumitomo Corporation of America, New York; and Autocon Composites Inc., Toronto.
Lawrence Technological University offers nearly 50 undergraduate, masters and doctoral degree programs in Colleges of Architecture and Design, Arts and Sciences, Engineering, and Management. Lawrence Tech pioneered the offering of day and evening classes 70 years ago, and now has a growing number of weekend programs. The University's Division of Continuing Education offers courses in leadership and management, computer science, insurance, engineering and more. Lawrence Tech also is home to the Advanced Technology Academy, a charter high school offering a challenging curriculum closely linked to the University's academic mission.