Four bridges constructed in the 1920s over the Grand Trunk Railroad in Detroit, now the Dequindre Cut Greenway, had become structurally deficient and in extremely poor condition. Wade Trim designed the replacement of three of these bridges (Wilkins, Division and Adelaide) and the removal and site restoration for the fourth bridge (Alfred) for the City of Detroit Department of Public Works. The bridge replacements were critical to transforming this abandoned greenway corridor into a multi-modal link and downtown recreational and commercial destination. The bridges also provided improved links for trucking in and out of Eastern Market. The project received the American Public Works Association Michigan Chapter’s (APWA MI) Project of the Year Award for Structures ($1 million to $5 million) at the Chapter’s Great Lakes Expo at the Grand Traverse Resort in Acme, MI.
The Dequindre Cut runs below street level and is one of a series of Link Detroit projects recently completed by the City of Detroit, in collaboration with several public and non-profit organizations, to connect 20 miles of continuous walking and biking paths linking downtown, midtown, Eastern Market, the Detroit riverfront and Hamtramck. The bridges are two-span, precast concrete arch structures with precast concrete wing walls that tie into existing cast-in-place concrete retaining walls. Wide sidewalks were incorporated into all the bridges to help pedestrians and other non-motorized users access Eastern Market, the Midtown Loop Phase IV pathway, and the Dequindre Cut. Bike paths were added at the Wilkins Street bridge and room for future bike paths was incorporated into the other bridges.
Special care was taken to work near existing utilities and buildings in this urban area. The bridge replacements are supported on steel H-piles that extend 130 feet to bear on hardpan. With the tight constraints of existing adjacent buildings, a two-stage piling operation was used during construction to minimize vibrations on the buildings. Vibration monitoring was conducted to measure effects to the existing buildings to prevent damage. In addition, with the tight right-of-way at each bridge, precast retaining walls were used instead of conventional concrete footings that would have interfered with building foundations. Precast concrete was utilized to eliminate bulking forming and supports necessary for cast-in-place concrete, again due to the tight constraints of the builidngs.
Bridge aesthetics were designed to blend with adjacent buildings and structures as well as other projects in the area. Concrete bridge and wall railings match the 1928 concrete rails while meeting the American Association of State Highway and Transportation Officials (AASHTO) requirements. A pedestrian fence design similar to existing bridge fencing along the Midtown Loop was incorporated into all four locations to create a similar look. Lighting on and under the bridges will provide security at the bridges and pathway. The streetlight fixtures mounted at each bridge corner match the lights of the Eastern Market improvement project. The renewed bridges are important features that draw visitors to the Dequindre Cut and provide access to key recreational and commercial destinations in Detroit.
Wade Trim Professional Engineer Robert Breen (center left) accepted the Project of the Year Award for Structures from APWA MI representatives at the Chapter’s Great Lakes Expo at the Grand Traverse Resort in Acme, MI.