Wis. Admin. Code Trans § Trans 212.10
When it is determined by the department that the maximum load under state law exceeds the load permitted on a bridge as described in the AASHTO manual, the bridge shall be posted for weight limits or closed. The department shall post or close bridges on the state trunk highway system and all other bridges for which the department is the maintaining authority. Each local authority shall post or close the bridges on highways under its jurisdiction. When a local authority fails to post or close a bridge as required, the department shall inform the county highway commissioner of the county in which the bridge is located and direct the county to post or close the bridge or cause the bridge to be posted or closed. Upon receipt of the department's notice and direction, the county shall post or close the bridge or cause it to be posted or closed. After the erection of signs or barriers associated with the posting or closing of the bridge by the county, the local maintaining authority of the bridge is responsible for the maintenance of the signs or barriers.
Wis. Admin. Code Department of Transportation § Trans 212.10