These rules lay the groundwork for a new British Standard covering box girder bridge design. The distinction in naming between a box girder and a tubular girder is imprecise. It is no longer in the top 20 of longest box girder spans. It is a 27-meter wide box girder bridge. It is of unusual design and is regarded as the first box girder bridge. The main girder of a box girder is fabricated from welded plates. These can be built using typical steel beams or a more complex box girder type. Errors in the box girder design caused it to collapse during its construction in 1970. It is a high-level hollow box girder bridge. To speed construction, the elevated trackway is built using precast concrete box girder bridge segments. It is the largest balanced cantilever cast "in situ" box girder bridge in Australia. The Middle Arm Bridge is a shorter box girder bridge. The opening was delayed by several months because of "box girder inspections". It is a multi-span balanced cantilever bridge with a post-tensioned concrete box girder structure. Later work was applied to bridge building, and the invention of the box girder.