ABSTRACT
Since World War II the evolution of military bridges has been driven by the increasing requirement for rapid deployment. In the mid-1960’s the Military Vehicle Experimental Establishment Christchurch, developed aluminium alloy ‘DGFVE 232’ specifically to give a much lighter bridge structure with easier and speedier construction. Fatigue crack growth of the more highly stressed bridge parts has to be monitored carefully, since worst case buried critical defect size is about 9 mm compared with the mild steel value of 90 mm. In the late 1960’s Christchurch designed the ‘battle group’ armoured vehicle launched bridge, the 24.4 metre long bridge being carried folded on the Chieftain tank hull in place of the gun turret. Other high strength to weight ratio alloys such as aircraft aluminium alloy type 7075 and titanium alloy Ti-6Al-4V might be considered for future bridges beyond BR 90.
