Federal money flows to full-scale earthquake tests of Alaska bridge pile connections

Engineers at North Carolina State University have worked since January 2024 on full-scale tests of the bridge joint where a steel H-pile, an H-shaped steel column driven into the ground, meets the cap-beam, the concrete beam that carries the bridge deck. The Federal Highway Administration added $80,000 on Sept. 17, bringing its cooperative agreement with the Alaska Department of Transportation & Public Facilities, a grant with federal involvement, to $210,058, records show. The first $130,058 was committed in October 2023.

The goal is guidance so that, in a large earthquake, unexpected damage does not interrupt service or force costly repairs. Alaska accounts for 11 percent of the world's recorded earthquakes, according to the Alaska Seismic Hazards Safety Commission.

The research has three stated aims: define the required embedment length (how far the pile extends into the concrete), determine the design actions on the footing (the earthquake forces it must resist), and develop a connection that resists them. Engineers assess the current connection, then build a model to predict cap-beam performance, likely using a strut-and-tie approach, which models the concrete as compression braces and tension ties. Further full-scale tests will examine alternative embedment and reinforcement details. The workplan also calls for cyclic and axial load tests.

The workplan does not describe the current connection as failed. Its stated rationale is uncertainty about embedment length and the accuracy of existing analysis methods. The project "will either affirm existing practice" or "identify deficiencies that will require revision, and possible retrofit," the project description says.

The federal award runs through June 30, 2028. The department lists the project at $476,860 in total funding, with completion expected in June 2027, and names Mervyn Kowalsky as principal investigator. The $210,058 is what the federal agency has committed so far. No department or university official is quoted.