The Des Moines City Council on Monday approved spending about $10 million to replace a bridge over Birdland Drive and make improvements and repairs to the Second Avenue bridge over the Des Moines River. Both bridges provide connections between downtown and the northern parts of the city and northern suburbs. The bridges, both of which were built in the 1930s, serve about 20,000 vehicles a day, according to the city. The bridge over Birdland Drive is classified as “structurally deficient,” Steve Naber, city engineer, said in a video about the projects. The designation “does not mean that the bridge is unsafe but it does mean some of the elements are in a condition that need significant work.” The Second Avenue bridge will receive a new concrete deck overlay, and steel beams and other components will be blasted and repainted. On Monday, the council awarded a contract to Jasper Construction Services Inc. of Newton, who submitted the low bid for the project.