The bridge, which connects the cities of Houghton and Hancock, is believed to be the heaviest and widest double-deck lift bridge in the world.
Photograph by Nathan Holth
M&M will lead the structural, electrical and mechanical design of the massive 82m-long, 16.5m-wide lift span. The span, which can be raised up to 30.5m, features an upper and lower deck capable of carrying a total of eight lanes of US Highway 41 and M-26.
The project will focus primarily on the replacement of the wire ropes used in hoisting the deck. M&M engineers proposed that replacement take place during winter months when the bridge can be left in the fully lowered position, with traffic maintained on the upper deck. The project also involves implementation of homeland security recommendations, provision of structural repairs to the operator’s house, and design upgrades to the barrier gates.
The Portage Lake Lift Bridge was completed in 1959 and is the fourth bridge to be built at the site. It replaced two steel swing bridges before it, and supersedes the original 1875 wooden swing bridge. "The Portage Lake Lift is no doubt an iconic structure due to its sheer size, but also its history of connecting the two communities," said Kevin Johns, project manager and movable bridge business unit leader with Modjeski & Masters.
