The Zilwaukee Bridge is a high-level, segmental

concrete Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most wid ...

bridge A bridge is a structure built to span a physical obstacle (such as a body of water, valley, road, or rail) without blocking the way underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually somethi ...

spanning the

Saginaw River The Saginaw River is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map accessed November 7, 2011 river in the U.S. state of Michigan. It is formed by the confluence of the Tittabawassee and S ...

in the U.S. state of

Michigan Michigan () is a U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest, upper Midwestern United States. With a population of nearly 10.12 million and an area of nearly , Michigan is the List of U.S. states and ...

. The river serves as the boundary between Zilwaukee Township and the city of Zilwaukee at this point, which is approximately north of downtown

Saginaw Saginaw () is a city in the U.S. state of Michigan and the seat of Saginaw County. The city of Saginaw and Saginaw County are both in the area known as Mid-Michigan. Saginaw is adjacent to Saginaw Charter Township and considered part of Greater ...

. The current eight-lane structure, completed in 1988, is the second such bridge at this location, replacing a four-lane

bascule bridge A bascule bridge (also referred to as a drawbridge or a lifting bridge) is a moveable bridge with a counterweight that continuously balances a span, or leaf, throughout its upward swing to provide clearance for boat traffic. It may be single- o ...

constructed in 1960. The present structure was designed to relieve traffic congestion along the freeway crossing it, resulting from repeated openings of the draw span for

lake freighter Lake freighters, or lakers, are bulk carrier vessels that operate on the Great Lakes of North America. These vessels are traditionally called boats, although classified as ships. Since the late 19th century, lakers have carried bulk cargoes of ma ...

traffic serving industrial sites along the river. The Zilwaukee Bridge is approximately in length and rises at its highest point.

History

While the need for a replacement of the original structure became acute soon after it was completed, the construction of the current structure was also plagued with difficulties. Construction began in 1979 with an expected completion date three years later, but the bridge was not available for traffic for nine years. The initial budget of $79 million had already been exceeded by $48 million, when at time in 1982, the bridge was roughly two-thirds completed, and a long segment weighing 6,700-ton (6,070 metric tonnes), not being properly counterbalanced, tipped down to being out of alignment, with the other end rising . A pier footing cracked, presumably due to resulting

stress Stress may refer to: Science and medicine * Stress (biology), an organism's response to a stressor such as an environmental condition * Stress (linguistics), relative emphasis or prominence given to a syllable in a word, or to a word in a phrase ...

. Once repairs were made, a new contractor was hired to complete the bridge once the initial contractor (Stevin Construction) and the state agreed to terminate their contract in exchange for both sides dropping their lawsuits over the accident. The new contractor developed a method of heating the concrete to allow construction during the winter. On some cold days these new sections could not be properly sealed against water infiltration, eventually leading to

spall Spall are fragments of a material that are broken off a larger solid body. It can be produced by a variety of mechanisms, including as a result of projectile impact, corrosion, weathering, cavitation, or excessive rolling pressure (as in a ba ...

ing as the water froze and expanded. Later during construction of new on- and off-ramps in the M-13 interchange on the bridge approach, workers uncovered an uncharted landfill containing PCB-contaminated waste, necessitating an

environmental cleanup Environmental remediation deals with the removal of pollution or contaminants from environmental media such as soil, groundwater, sediment, or surface water. Remedial action is generally subject to an array of regulatory requirements, and may also ...

. The segment of

freeway A controlled-access highway is a type of highway that has been designed for high-speed vehicular traffic, with all traffic flow—ingress and egress—regulated. Common English terms are freeway, motorway and expressway. Other similar terms ...

utilizing the Zilwaukee Bridge is part of

I-75 Interstate 75 (I-75) is a major north–south Interstate Highway in the Great Lakes and Southeastern regions of the United States. As with most Interstates that end in 5, it is a major cross-country, north–south route, traveling from St ...

and US 23.

Interstate 675

I-675 was built, in part, to help traffic bypass the original drawbridge while the current high-level Zilwaukee Bridge was being proposed and constructed, in addition to providing better access into and through downtown

. During bridge maintenance, I-675 is used as a

detour __NOTOC__ A detour or (British English: diversion) is a (normally temporary) route taking traffic around an area of prohibited or reduced access, such as a construction site. Standard operating procedure for many roads departments is to route an ...

route for traffic.

Maintenance

In April 2008, work crews replacing

bridge bearing A bridge bearing is a component of a bridge which typically provides a resting surface between bridge piers and the bridge deck. The purpose of a bearing is to allow controlled movement and thereby reduce the stresses involved. Possible causes o ...

s unexpectedly drilled into several reinforcing steel bars in the bridge. The $3.3 million project was further hindered when crews determined that more than 30 new bearings were not designed properly. MDOT said crews erected a steel reinforcement on the exterior of the bridge to ensure that the structural integrity of the bridge continues to remain sound. On October 21, 2008, the bridge opened up to north and southbound traffic once again. On December 7, 2012, the ''

Detroit News ''The Detroit News'' is one of the two major newspapers in the U.S. city of Detroit, Michigan. The paper began in 1873, when it rented space in the rival ''Detroit Free Press'' building. ''The News'' absorbed the ''Detroit Tribune'' on Februar ...

'' reported that a $70 million MDOT program would commence the following April to replace 154 bearings, rebuild 4 miles of I-75, replace the Janes Road bridge, and repair the

CSX CSX Transportation , known colloquially as simply CSX, is a Class I freight railroad operating in the Eastern United States and the Canadian provinces of Ontario and Quebec. The railroad operates approximately 21,000 route miles () of track. ...

and Wadsworth Road rail bridges in the area. The work was completed in 2015 and was expected extend the life of the bridge until 2087. During 2014, special custom-made jacks were put into place as a stop-gap measure while bearings were replaced.

References

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External links

Zilwaukee Bridge
at Michigan Highways * {{Central Michigan Buildings and structures in Saginaw County, Michigan Interstate 75 Bridges completed in 1988 Transportation in Saginaw County, Michigan Road bridges in Michigan Bridges on the Interstate Highway System Bridges of the United States Numbered Highway System U.S. Route 23 Concrete bridges in the United States 1988 establishments in Michigan