Closings and detours involving Second Street from Mesaba Avenue to Fourth Avenue West in Duluth will begin Monday, St. Louis County administrator Kevin Z. Gray announced. The traffic disruption will be needed to allow for infrastructure work below Second Street and to replace windows in the skywalk above it, according to a news release from the county. The skywalk connects the St. Louis County Courthouse to the Third Street parking ramp. Signs will be posted to indicate when lane closure are in place or when a detour to Fourth Street is required. The projects are expected to be completed by mid to late October.