Chicago city officials celebrated the 90th birthday of the Michigan Avenue Bridge by recalling its engineering marvel as well as its key link to development both north and south of the Chicago River.
As the world’s first double-leaf, double-deck bascule trunnion bridge ever built, “it’s one of the most recognized bridges in the world,” says Thomas Powers, acting commissioner of the Chicago Department of Transportation. The May 14 celebration also marked the opening of the fifth season of the Friends of the Chicago River’s McCormick Bridgehouse & Chicago River Museum, located along the new Chicago Riverwalk at the southwest end of the bridge.
Inside the Bridgehouse Museum, guests can enter the gear room and, on select days, watch the gears as they lift the bridge with two 100 horse-powered engines. Also, the history of the Chicago River is told on all five levels of the bridge tender house. John Chikow, president and CEO of The Greater North Michigan Avenue Association, also announced the formation of a new Chicago Riverwalk council “to put our marketing muscle behind marketing the riverwalk as one of the great destinations that the city has to offer.”
Stretching from east of the Michigan Avenue Bridge to State Street, the riverwalk opened last year. Skidmore, Owings & Merrill prepared its long-range plan, and Chicago architect Carol Ross Barney and her associate John Fried designed the waterfront pathway where amblers can watch passing boats or stop at riverfront cafes.
Designed by Thomas Pihlfeldt, Hugh Young and Edward Bennett, the Beaux-Arts style Michigan Avenue Bridge has a 220-ft clear span, and a 256-ft trunnion-to-trunnion span. It’s 92 ft wide and has a leaf weight of 4,100 tons. It sits 17 ft above the water, and has average daily foot traffic of 35,909 and average daily vehicular traffic of 33,300.
Four ornate bridge tender houses anchor each corner and each double-deck leaf is supported by four deck trusses.