A University of Arkansas researcher has been awarded an $800,000 federal grant to study the design of stud shear connectors in composite steel bridges, with the goal of determining how loads transfer from concrete to steel via the connectors.
The four-year study, led by associate professor of civil engineering Gary Prinz, will also examine the strength and fatigue limits of the connectors in hopes of aiding more efficient design. More efficiently designed bridges generally mean affordable bridges.
The grant comes from the National Cooperative Highway Research Program.
“We generally make assumptions that all the load goes right through that little stud and that no other forces are transferred through friction or adhesion between the concrete and steel,” Prinz said in a news release. “So in our project we’re tasked with determining precisely how the different loads interact and quantifying the different load paths that can occur.”
Prinz is the director of the Grady E. Harvell Civil Engineering Research and Education Center, named for the head of W&W/AFCO Steel in Little Rock. Much of the work for the study will be done at the center, which opened in July. That includes construction of 60-foot-long bridge sections for large-scale fatigue testing.
In all, Prinz anticipates doing five large-scale tests, and numerous smaller component-level tests. He and his research team will also visit bridges that are under construction.
If the terms of the grant are met, the study will likely contribute to federal design standards for bridges, with potential consequences for the design of every composite steel bridge moving forward.
“The measurement problem that we’re facing here,” Prinz said in the release, “is trying to understand how much load goes through something that’s embedded in concrete.
"And the complicated part is that the loads we’re trying to measure are perpendicular to the direction of the studs — so we’re trying to measure shear transfer in an element that’s embedded in concrete, and that’s not an easy thing to do.”