Numerical rating system (NRS)
a) The “Numerical Rating System” for bridge inspection assigns a “Unique Rating Number” (URN) to represent the physical condition of a bridge. Lower the URN more serious is the deteriorated condition of a bridge. The system thus helps in identifying progressive deterioration in the condition of a bridge. URN can be stored in a computer for quick retrieval and fixing priorities for repairs or rehabilitation.
b) The URN of a bridge is arrived at based on the condition of components and a “condition rating number” (CRN) assigned to each of them. The various components of a bridge in sequence, are : i. Foundations and flooring, if any, ii. Masonry / concrete in substructure, iii. Training and protective works, if any, iv. Bed blocks, v. Bearings and expansion arrangements, vi. Superstructure – Girders / Arch / Pipe / Slab etc. vii. Track structure.
