Design and construction of a twin-box girder bridge over major interchange in Montreal

摘要

A major reconstruction project at the intersection of highways A15 and A40 in Montreal has been underway for almost two years. The project comprises - among other road and bridge works - a construction of an overpass connecting A40 East to A15 North over A40. The paper presents main structural features of the overpass and its construction. The new structure had to meet several constraints such as the interchange geometry, a requirement to minimize traffic disruptions during construction as well as the aesthetics of the structure which will be visible from all angles by drivers and passersby. A design comprising three-span horizontally curved steel box girders with a concrete deck was chosen for this structure. Span lengths of 44.4 m + 64.4 m + 44.4 m and a constant structural depth not exceeding 2.30m were selected to meet the design criteria. Two trapezoidal box girders curved in horizontal and vertical planes support two lanes of traffic and two shoulders (total width of 12.9m). The structure is designed as Lifeline Bridge and pot bearings with shear keys were necessary to meet both service and seismic loading conditions. Anchors to rock were also used on piers foundations. Fabrication of structural steel was done by Canam-Bridges, which delivered ten sections of the complete superstructure (total steel weight 458 tons). The final assembly was conducted in one night using ten mobile cranes and no temporary supports. The viaduct was opened to traffic in August 2012.