State transportation officials said this morning that they have removed 26 panels from the Sumner Tunnel after they were found to be loose, creating the risk that they could fall into the roadway.
The discovery came during an overnight inspection, and it follows the removal last week of 117 panels in the Callahan Tunnel that were loose. Both inspections were conducted after one panel in the Callahan Tunnel fell into the roadway just over a week ago, tying up traffic for several hours. The panel did not hit a car, and no one was injured. Three other panels were also immediately removed.
The panels, scattered throughout the tunnl, were removed after a series of “pull tests’’ — pulling on them from the top and bottom to see if they were loose.
Officials said today that the bracing behind the panels in the Sumner Tunnel were found to be weakened by corrosion. Moisture from washing the panels, underground leakage, grime, brake dust, and diesel exhaust all contribute to the corrosion.
Officials said the panels on the Sumner Tunnel will be replaced in the coming weeks, but the replacement of panels inside the Callahan could take longer.
Officials also say they are looking into a lining system that could possibly better stand the test of time, such as fiberglass.