Collapse Angers Bridge

collapsed basse-chaîne bridge

soldiers stationed in region used bridge, , 2 battalions of same regiment had crossed earlier day. third battalion arrived during powerful thunderstorm when wind making bridge oscillate. when soldiers began cross, bodies acted sails, further catching wind. survivors reported had been walking if drunk , barely keep falling, first 1 side , other. usual in crossing bridge, soldiers had been ordered break step , space farther apart normal. however, efforts match swaying , keep balance may have caused them involuntarily march same cadence, contributing resonance. in case, oscillation increased. @ time when bridge covered 483 soldiers , 4 other people (though police had prevented many curiosity seekers joining march), upstream anchoring cable on right bank broke in concrete mooring, 3 4 meters underground, noise badly done volley firing squad . adjacent downstream cable broke second later, , right-bank end of deck fell, making deck slope steeply , throwing soldiers river. many of fell saved fellow soldiers had not yet crossed , residents of angers came rescue, total of 226 people died.

the failure attributed dynamic load due storm , soldiers, particularly seem have been in step, combined corrosion of anchors main cables. cable anchorages @ angers found highly vulnerable, surrounded cement, believed rustproof them indefinite future. however, wire strands separated cement surrounds. allowed water penetrate , corrode wires.