Metal box girders with a cellular plastic core - for high inertial stiffness to wt. ratios

摘要

Box girders (I) are made from twin channels linked by a polyurethane or similar foam resin core enclosed by relatively light gauge side plates. (I) are lighter than conventional 'I' girders or all-metal box girders of equiv. stiffness (as characterised by flexural or torsional moments of inserts). (I) are cheaper than corresp. latice girder structures. Adhesion between the foam core and the metal components may be due to natural compatibility (e.g. polyurethane resin + mild steel), or due to use of interfacial primers on internal anchorage hooks.