The King Street Bridge takes King Street over the Yarra River in Melbourne, Victoria, Australia. The bridge continues south as an elevated viaduct, with the Crown Casino and Entertainment Complex built around it in later years. The bridge was designed in 1959 by Utah Australia for the Country Roads Board, and constructed over the next two years, being opened on 12 April 1961. It was of a welded, deck-girder, suspended-span construction with spans up to 49 m long.
Soon after completion, on 10 July 1962, one span collapsed under the weight of a 47 ton semi-trailer, though the weight was within the bridge limits. The subsequent Royal Commission found that bridge failed with a brittle fracture on a very cold Melbourne winter day. The Commission identified the cause of girder failure was due to cracked welds. The fabricator was not familiar with welding low-alloy steel and the steel supplied was high in carbon making it difficult even for an experienced fabricator. The cracks in the welds were not discovered by inspectors of both the fabricator and the Country Roads Board.
As originally constructed the bridge had 8 lanes across the Yarra River - 2 through lanes in each direction connecting King Street to Kingsway, in addition to 2 lanes on each side that connected to Yarra Bank Road. In later years the development of Crown Casino closed Yarra Bank Road, and the bridge ramps were connected to the basement carpark of the complex.
This post is part of the Sunday Bridges meme.