Box girder bridges

Abstract

Bridges of single and double box girder design described in this article, include: the West Gate Bridge, Melbourne, Australia; the Rio-Niteroi Bridge, Brazil; the Jay Road Bridge and the Erskine Bridge, Scotland; the Wye Bridge, England; the Milford Haven Bridge, Wales; and the Koblenz Bridge, Germany. Special attention is paid to the West Gate Bridge because of its collapse during construction, and this review of box girder design concludes that: it is impossible to predict or to control, during fabrication and erection, the contours of the surfaces of the flanges and webs of very large boxes using thin steel plates. Calculations made on the basis that the flange and web surfaces are plane do not provide a reliable or useful guide to the designer. It is not possible to make a safe assessment of stresses when extensive curvature and distortion of box surfaces has occurred. Stiffer, well proportioned, twin or multiple box girders, should generally be used instead of single wide box girders, and the former girders provide a sound and useful method of construction. Reinforced or pre-stressed concrete box girders can be used without much difficulty in many site conditions for spans not exceeding 195 m. The relative economy of box girder bridges in steel or concrete will largely depend on local conditions governing supply of material. /TRRL/