Steel Bridge Design Handbook: Load Rating of Steel Bridges

Load rating is defined as the determination of the live load carrying capacity of a bridge using as-built bridge plans and supplemented by information gathered from the latest field inspection. Load ratings are expressed as a rating factor or as a tonnage for a particular vehicle. Emphasis in load rating is on the live-load capacity and dictates the approach of determining rating factors instead of the design approach of satisfying limit states. Existing highway bridges are rated to prioritize a bridge owner’s needs, assure the traveling public’s safety, and facilitate the passage of goods. Bridges that cannot safely carry statutory loads, based on a load-rating evaluation, should be load posted, rehabilitated or replaced. This module informs designers of load ratings, and discusses the load and resistance factor rating (LRFR) methodology used for load rating evaluation.\n