The Post Street bridge in downtown Spokane is seen March 27, 2019. The city has closed the bridge to all motor vehicles, citing a structural analysis which found the aging span can’t safely hold that much weight. (Jesse Tinsley / The Spokesman-Review)

The city of Spokane on Friday closed the Post Street bridge to all motor vehicles, citing a structural analysis which found the aging span can’t safely hold that much weight.

Pedestrians and bicyclists can continue to use the center of the bridge, though the sidewalks also are off-limits, the city said.

The 333-foot reinforced concrete bridge was built in 1917 and widened in 1937. It also carries a 54-inch sewer line.

The city had planned to begin replacing the bridge this year, but new steel tariffs and lumber costs added an estimated $4 million to the $22 million the city had budgeted for the project.

The city now says construction should begin in spring 2020.

KPFF Consulting Engineers conducted the structural analysis while the project was on hold, and is working on the design of the replacement bridge.

The bridge, which crosses the Spokane River at the Washington Water Power building, was reduced to one lane in 2013 after it was deemed structurally inadequate for more traffic. Weight restrictions were also in place for large trucks and trailers.