People who live near the twin Tacoma Narrows bridges are about to get some relief from traffic noise.

On Sept. 8, construction will begin on a three-month project to build noise barriers along the new bridge, the state Department of Transportation announced Thursday.

Since the bridge opened last year, neighbors have complained about the loud clunking sounds as thousands of vehicles pass over the expansion joints on either end of the eastbound Highway 16 span.

Readers told The News Tribune last summer that it sounds like a giant percolator, or a giant troll trying to escape from a box. DOT officials say neighbors have compared it to the sound of a loud zipper.

“Engineers hope to zap the zipper sound with noise-absorbent panels placed on the sides of the bridge anchors,” the DOT said in a news release. “These panels will also be placed on four noise-barrier walls built on top of existing traffic barriers alongside the bridge. The noise walls are designed to mimic the geometric shape of the nearby anchorages.”

The DOT said barriers can reduce noise levels by 10 to 15 decibels.

Construction is expected to be complete by the end of the year. The contractor is Tri-State Construction Inc. of Bellevue. A DOT spokeswoman could not immediately say Thursday how much the contract costs or where the money is coming from.

Hunter T. George: 253-597-8530