Riverside County will spend $32.7 million to replace the two Van Buren Boulevard bridges on the border of Riverside and the Jurupa/Pedley area and make associated road improvements.

The bridges, each 1,000 feet wide, are seismically unsound and inadequate to accommodate the amount of traffic carried by Van Buren Boulevard, according to an evaluation by the State Department of Transportation.

On Tuesday, the Board of Supervisors approved seeking bids for new bridges over the Santa Ana River in western Riverside County.

The structures are separated by 50 feet, which allows for building a new bridge between them. Traffic will be shifted to the new structure while one of the existing bridges is replaced, according to the engineering firm hired by Riverside County.

The southbound bridge was constructed in 1939. The northbound bridge was added in 1958. Both were extended in length in 1971 to span the entire flood plain.

Twelve years ago, the state recommended strengthening the bridges to withstand earthquakes. However, a later evaluation urged total replacement after finding porous, liquefied and weakened soil at the sites.

After working with Dokken Engineering in San Diego, the county has cleared state and federal regulations to secure construction permits. Juan C. Perez, the Riverside County Director of Transportation, provided details of the project.

The bridges lack standard shoulders, a sidewalk for pedestrian crossing and adequate number of traffic lanes to accommodate expected future traffic. The project will provide replacement bridges of approximately 1,005 feet in length and reconstruct the 2,600 feet of approach roads to remedy those conditions.

The project will provide a state-of-the-art structurally and seismically sound bridge with complementing aesthetic features.

The project will provide standard shoulders, adequate bridge width for a future third lane in each direction and sidewalks. The proposed bridge will have six lanes, with interim striping for four lanes.

Nearly three-quarters of the funding will come from the federal fund for seismic safety retrofitting.

The existing structure has four lanes, but the federal retrofit money doesn't cover road widening. The widening cost will be borne by Transportation Uniform Mitigation Fee regional funds.

The project will provide traffic signal and intersection changes, street lighting and other improvements.

The Riverside County Department of Transportation will accept bids through March 25.

Reach Laurie Lucas at 951-368-9569 or llucas@PE.com