Reengineering concrete: Pitt professor develops computer code to produce cheaper, lighter design

Amir Alavi was trained as a civil engineer, but he was asked a couple of years ago to work with researchers at the University of Pittsburgh Medical Center to help develop a biomedical femur to help patients with thigh problems.

That work with evolutionary computation, where artificial intelligence is given a problem and asked to randomly design thousands of potential solutions, got the assistant professor of engineering to think about how the same process could be applied to the work civil engineers do to design roads, bridges and other transportation projects at lower costs. As a result, he has developed a computer code to design patterns for metamaterial, in this case ultralight and ultrasturdy concrete that could revolutionize the construction industry by cutting costs 30% or more by reducing the amount of material used to create the product without cutting its performance or life expectancy.

“I noticed this [evolutionary computation] has a lot of utility for civil engineering,” Alavi said. “We just give it some situations and tell it to find the solutions. It’s going to reshape our design system.”

Using the same combination of sand, gravel and cement, the computer-generated designs come up with different shapes and applications. The process is so promising that Alavi has contracts with the Pennsylvania Department of Transportation to prepare designs for bridge decks and the Pennsylvania Turnpike Commission for sound barriers through the University of Pittsburgh’s Impactful Resilient Infrastructure Science and Engineering Consortium. That program, based at the Swanson School of Engineering, is a collaboration of government agencies, private companies and academic researchers that looks for solutions to long-term road and bridge issues.

To the layman, it would seem that the best concrete would be the sturdiest, most solid combination of the basic ingredients. But Alavi said computer simulations show that isn’t necessarily the case and that changing the shape and design of a block of concrete to include open voids with arches and other elements can improve the strength and flexibility of the concrete while using less material.

Rather than a standard rectangular block, the computer design can lead to funky-looking blocks that have a series of holes in them or ends that look like plus signs and middles that look like an hourglass.

For roads or bridge decks, the computer designs often have additional qualities that make them desirable.

For example, some designs can compress as much as 20% and return to their original shape with no damage. That means the weight of heavy trucks would cause little or no damage to the pliable surface but could cause damage to more rigid concrete.

“Humankind can’t do that kind of design,” Alavi said. “Now we have the technology to play with and use it to come up with the best and least expensive options. It’s a range of options and solutions, ultimately.”

Alavi said he and his students can give the computer code outcomes they want in a design, and the computer spends the next 24 to 36 hours producing possible designs and rating them by factors such as cost, strength and durability. Then the staff reviews the potential designs to determine which one is the best fit for each project.

The process is ideal for precast concrete, where suppliers create a mold and fill it with concrete to create the product, but it also can be used in traditional construction.

The two projects Alavi is developing through IRISE could be the first practical applications of computer-generated concrete design.

For the PennDOT project, which began in January, Alavi has a $250,000 contract to develop a design for an ultralight ultrastrong concrete bridge deck over the next two years. His group will produce test samples for potential deck designs.

“PennDOT is always looking for ways to be innovative, and we believe this research can help accomplish that,” the agency said in a statement. “We are excited to see where the idea of lightweight metamaterial concrete can fit into our industry and how it could advance the field of bridge construction.”

For the turnpike, Alavi will design a new type of sound barrier to reduce the amount of highway noise that goes into nearby neighborhoods. The initial contract, which starts this fall, will have the team develop small-scale models to conduct lab tests for $140,000 and an additional $200,000 if the agency decides to use the concept in the later stage of construction of the Mon-Fayette Expressway.

That new toll road started construction earlier this year and will take about five years to complete, linking Route 51 in Jefferson Hills with Route 837 in Duquesne.

“We’re looking for a way to be a better neighbor,” Ed Skorpinski, the turnpike’s engineering project manager, said in an interview. “Pitt came to the turnpike about this idea. We are hoping for savings on material.”

Alavi said he believes in the system, which may be the only one of its kind in the country used for civil engineering projects.

“I’m confident this is going to be the future of construction design,” he said. “I’m 100% sure of it.”