Abstract
The outline of the report of the commission of inquiry concerning the collapse of the “de la Concorde overpass” was described here. This concrete bridge was constructed in 1971 in the suburbs of Montreal in Canada and collapsed on September 30, 2006. The total length and the width were 61. 8 m and 27. 4 m, respectively. Twenty PC hollow girders (27. 4 m) rested on beam seats located at the ends of the cantilevers of the abutments, directly under the expansion joints. The improper rebar detailing during design, the improper rebar installation at the time of construction, and the low quality concrete used for the abutments are pointed out as the principal physical causes. The lack of shear reinforcement in the thick slab, the absence of an adequate protection of the thick slab against water, and the damage caused during the repair work are mentioned as the contributing physical causes. Wide-ranging recommendations to prevent similar accidents are described.
