University researcher builds bridge to Earth Day

Ibrahim Al-Khattat examines a 35-foot-long demonstration bridge. Students from local schools are planning to construct a similar bridge at Kirkwood Elementary School, based on a design by Al-Khattat’s Oakdale-based company, Sustainable Science and Technology, Inc. Photo by Rex Bavousett.

Al-Khattat is founder and president of the non-profit American Institute of Sustainable Science and Technology, Inc., based at the UI’s Technology Innovation Center, Oakdale Research Campus. He says it’s a project that may pay long-term dividends in community education.

"Just about everything used in the project is commercially worthless by present-day standards," says Al-Khattat, an adjunct associate professor of civil and environmental engineering. "I hope to get the community behind the project and make people aware of science and environmental conservation as tools of development and wealth generation. This technology opens up a vast new field of ‘green’ engineering research and applications. It amounts to a profitable formula for saving the mature forests."

The project is a 62-foot-long bridge to be built on the grounds of Kirkwood Elementary School in Coralville, where it will span a creek and provide access to the school’s 35-year-old, one-acre environmental campus. Al-Khattat adds that the city of Coralville (which eventually will own the completed bridge) is providing logistical support, while the University of Northern Iowa’s Department of Industrial Technology will manufacture the essential metal connectors.

Laborers will include students from Kirkwood Elementary, Northwest Junior High, and West High schools and their parents, teachers, and other volunteers.

The design, provided by Al-Khattat’s institute, involves a latticework of logs cut from wild, small-diameter black locust trees, fitted into metal connectors, and tensioned and braced together with steel cable. The deck of the bridge will consist of discarded shipping pallets that would otherwise end up in landfills.

"Black locusts grow along highways as a weed tree," Al-Khattat says. "They’re available almost for free; all we have to do is cut it. Yet it does not decay and has twice the compressive strength of concrete." He says that the ring structure, when left intact in the form of a round log, gives the wood tremendous strength and resiliency, a quality lacking in commercial lumber derived from mature logs sliced into boards.

One obstacle to beginning the project, according to Kirkwood Elementary principal John Saehler, is that the ends of four-inch diameter black locust logs need to be trimmed so that they can fit into the metal connectors. Al-Khattat acknowledges the delay, adding that he is arranging to purchase a device, similar to a large pencil sharpener, able to trim each log in seconds.

In the meantime, both the students and Al-Khattat have been moving ahead. Saehler says that some of his Kirkwood Elementary students assembled 10-foot-wide geodesic domes from 2-foot-long sticks and connectors some months ago. Similarly, junior high students participated in the assembly after processing the logs themselves.

And, on a lot that the institute owns in Coralville, Al-Khattat has built a 20-foot-wide dome and a 35-foot-long bridge as demonstration models. The demonstration bridge, which closely resembles the bridge planned for Kirkwood Elementary, proved its durability by withstanding hurricane-force winds without damage during the severe storm that hit eastern Iowa on June 29, 1998.

"This is just the tip of the iceberg. There are hundreds of deteriorating bridges across Iowa that need to be replaced," says Al-Khattat. He has earned European Union and British funding, a patent and a top invention award from the British Design Council for the new technology, formally known as LPSA (Light Post-tensioned Segmented Arch) technology. Supported by a research grant from the Iowa Highway Research Board and the Iowa Department of Transportation, an alliance composed of the institute, Buchanan County, and UNI is planning to design, construct and test a heavy-duty LPSA suspension bridge within Buchanan County.

"I’m tweaking engineering and science through a simple requisite: environmental sustainability," Al-Khattat says. His message: "Don’t take from the Earth more than you put in."

Article by Gary Galluzzo