A structural assessment of the Wilson Tunnel on Likelike Highway has identified additional deterioration of stainless-steel rods supporting the ceiling, state Department of Transportation officials said Thursday.

The assessment should be completed by today, when the Transportation Department says it will finalize a plan for repairs.

The Likelike Highway tunnel was closed in the town-bound direction last weekend after eight steel rods that help support the ceiling were found deteriorated, and crews installed wooden support beams. Inspectors also found cracks in the concrete near vents in the tunnel.

“During the closure, HDOT crews and a structural engineering consultant identified 22 other rods that were damaged,” according to a news release.

The left lane of the tunnel remains closed, and “crews are finalizing assessments of the more than 560 stainless steel rods, and the 5,500 feet of 5-inch thick reinforced concrete ceiling in both portals of the Wilson Tunnel to determine the cause and extent of damage by Friday.”

The department said it would take an estimated three to four weeks before the emergency repair work begins after new rods have been made and delivered.

During repair construction, one lane will remain open in the Honolulu-bound direction during peak travel times, although construction might require intermittent full closures of the tunnel, the DOT said.

“The safety of our residents, visitors and staff is our No. 1 priority,” said Ed Sniffen, state Highways Division deputy director. “The Wilson Tunnel continues to be a safe route to utilize.”

The Wilson Tunnel opened to traffic in 1960, according to the DOT. The Honolulu-bound tunnel is 2,775 feet long, and the Kaneohe-bound side is 2,813 feet.