Inside the Zilwaukee Bridge: Why the Z-Bridge almost wasn’t completed

The 4-lane highway initially crossed Saginaw River as draw bridge

SAGINAW, Mich. – Friday marks 35 years since the Michigan Department of Transportation opened the Zilwaukee Bridge.

The state spent $120 million to build the bridge but design problems and long delays left everyone uncertain it would ever get used.

Now, the bridge is very busy. Around 21 million vehicles a year ride up and over the Saginaw River. It’s also one of Michigan’s most storied.

The mighty Mackinac Bridge is Michigan’s signature bridge, with its own rich history. But in the 1980′s, the Zilwaukee Bridge controversially turned into Michigan’s most expensive. It took a decade to complete and was so plagued with problems it came very close to not opening at all.

Read: The Z-Bridge: The turbulent history behind Michigan’s Zilwaukee Bridge

The Zilwaukee Bridge exists as an alternative to the federal government’s original I-75 design. The 4-lane highway crossed the Saginaw River as a draw bridge.

The original Zilwaukee Bridge as a four-lane draw bridge. (MDOT/Michigan Highways)

Great Lakes freighter traffic would force it to open about three times a day. Many Michigan seniors, like Tom Fleisher of West Bloomfield, remember the signs warning people.

“We had to wait in line. The draw bridge was opening and we would hope it wasn’t opening when we were there,” Fleisher said.

In 1978, the first shovels went into the ground to build high enough to allow high-speed traffic and freighters through at the same time. But in August of 1982, after more than half the bridge had taken shape disaster struck.

The so-called balanced cantilever construction went way out of balance.

“There were engineering calculations done that said ‘this needs to be here’ and ‘this load needs to be here’ and ‘this counterweight needs to be here6′ and it simply was not followed,” former MDOT Chief Bridge Engineer Matt Chynoweth said.

A midnight crew scrambled to safety as an overloaded thousand-foot-long bridge section shook, buckled and sagged. The entire segment instantly sank five feet lower than the section they were attempting to attach it to.

Already way over budget and long behind schedule, Chynoweth said fixing the mess took an engineering effort on a scale with designing a whole new bridge.

“We lifted and tilted and jacked it into place. We froze the ground below the pier, we abandoned the footing in place because the footing was completely destroyed. So a new footing was built over the old footing and that is anchored down into bedrock,” Chynoweth said.

The setback took two years and $6 million more unbudgeted dollars. There were discussions about abandoning the project completely.

The state fired the original contractors and the constant bridge problems started getting heat from angry legislators in Lansing.

The building and opening of the Zilwaukee Bridge:

Yet, five years later than expected, on Dec. 23, 1987, the first vehicles crossed the northbound side. The southbound side opened the next summer.

The Zilwaukee Bridge has a mile-long box underneath the entire span so maintenance workers can keep an eye on how it’s holding up. They ride electric cars inside to inspect and do repairs.

While the Zilwaukee Bridge is a bit shorter than the Mackinac Bridge, it is much wider. It has 1592 concrete segments that weigh about 160 tons. They are held together with 20,000 miles of steel cable.

Engineers said even after 35 years, it’s holding up well. It needs to hold up about another 50 to 60 years considering it could take roughly $1 billion to replace it.


About the Authors:

Rod Meloni is an Emmy Award-winning Business Editor on Local 4 News and a Certified Financial Planner™ Professional.

Kayla is a Web Producer for ClickOnDetroit. Before she joined the team in 2018 she worked at WILX in Lansing as a digital producer.