box girder

plural box girders

1. A steel beam with a hollow rectangular cross section; used for constructing bridges etc.

   An all-welded, box section underframe, incorporating box girders which run the full length of the locomotive, is welded to stress-bearing bodysides with partition walls forming reinforcing cross members.

   1962 June, “Beyond the Channel: U.S.S.R.: A 3,000 h.p. diesel-hydraulic from MaK”, in Modern Railways, page 416

   1 more example

   The Britannia Tubular Bridge is immediately west of Menai Bridge Station on the Holyhead main line. In design it consists of two continuous box girders of rectangular cross section, one for each track. It was opened in 1850.

   1946 May and June, “The Why and The Wherefore: Miscellanea”, in Railway Magazine, page 198

   Synonyms: box beam, tubular girder