Old I-74 piers to be demolished with explosives Oct. 15

Certain piers of the old I-74 bridge, among the last remnants of the iconic bridge, will be demolished with explosives this fall and winter. 

The demolition contractor, Helm Group, will use controlled explosives to remove several standing concrete piers, the former support structures of the bridge, between Bettendorf and Moline the morning of Oct. 15, beginning as early as 7 a.m.

In this file photo, crews place a top portion of the two towers on to barges during removal of the old Interstate 74 bridge towers and cables on Aug. 28, 2023. Explosives will again be used on on Oct. 15 on four of the piers. 

GARY L. KRAMBECK

A second round of pier demolition is slated for sometime this winter, according to the Iowa Department of Transportation. 

It’s among the final steps of demolishing the twin spans of the old I-74 suspension bridge, the first built in 1936 and the second span completed in 1960. 

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The contractor will use controlled explosives on four of the 22 piers — west-bound Piers B, C and D and east-bound Pier D.

The load charges are placed in vertical holes drilled in the remnants of the four piers, which are now just 2-3 feet above water. The explosives will be roughly 7-10 feet below water, said Mark Brandl, an onsite engineer contracted by the Iowa DOT. 

Once the piers are blasted, the concrete rubble and rebar will be removed from the river by excavators, according to Brandl.

A pair of piers at Pier K, located in Sylvan Slough near the Moline riverfront, will remain to avoid disturbing a population of endangered mussels.

Another two piers are planned to be demolished with explosives later this year.

In this file photo, Last pieces of the old I-74 bridge is still being demolished Thursday, Aug. 3, 2023 between Bettendorf and Moline. The other towers and cables were brought down in late August. Some of the piers will be removed by explosives on Oct. 15. 

GARY L. KRAMBECK

The contractor is removing the other 14 piers manually with a hammer excavator. Already, eight on the south end have been dismantled, Brandl said. 

The use of explosives isn’t necessary for demolishing the piers, Brandl said, but its quicker and cheaper than removing them manually with an excavator.

However, the contractor is only allowed to use explosives to demolish six of the 20 piers slated for removal as 12 are in an environmentally protected area and another two are too close to the Bettendorf levee.

The explosives will close the bridge, pedestrian path, and river to traffic on Sunday, according to IDOT. 

A map of restricted areas ahead of the planned demolition of the old I-74 bridge piers the morning of Oct. 15. Contributed. 

The new I-74 bridge will be closed to traffic for about an hour the morning of Oct. 15, with a detour posted routing traffic to I-80, I-280 or the Centennial Bridge. The pedestrian bridge path will be closed for about 24 hours beginning the night of Oct. 14. 

The river will close to traffic, too. The main navigation channel will be closed for up to 24 hours, beginning at 6 a.m. Oct. 15. Areas outside the main navigation channel will be closed for up to 72 hours, according to the Iowa DOT.

The towers and suspension cables were taken down with explosives earlier this summer, drawing crowds to the site and onlookers to the live stream online.

Officials encourage the public to view the demolition online via a livestream: iowadot.gov/i74riverbridge/Traffic-Cameras.

The new I-74 bridge, completed and opened fully in 2021, was decades in the making and cost about $1 billion. 

Photos: Controlled explosives take down the last of the old I-74 bridge on Sunday.

Controlled explosives take down the last of the old I-74 bridge on Sunday.

GARY L. KRAMBECK

Crowds of people watch at the intersection of Brown street and Kimberly road during the controlled explosives taking down the last of the old I-74 bridge on Sunday.

GARY L. KRAMBECK

Ducks take flight after loud controlled explosives take down the last of the old I-74 bridge on Sunday.

GARY L. KRAMBECK

People watch at the intersection of Brown street and Kimberly road during the controlled explosives taking down the last of the old I-74 bridge on Sunday.

GARY L. KRAMBECK

People in boats and cabin cruisers anchor at a distance to watch the controlled explosives to take down the last of the old I-74 bridge on Sunday.

GARY L. KRAMBECK

Crowds of people watch at the intersection of Brown street and Kimberly road during the controlled explosives taking down the last of the old I-74 bridge on Sunday.

GARY L. KRAMBECK

The Interstate 74 bridge and on ramps in downtown Bettendorf were closed for the controlled explosives to take down the last of the old I-74 bridge on Sunday.

GARY L. KRAMBECK

Crowds of people watch at the intersection of Brown street and Kimberly road during the controlled explosives taking down the last of the old I-74 bridge on Sunday.

GARY L. KRAMBECK

A cyclist looks at the old I-74 bridge, which within minutes was set to explode into the water, Sunday Aug. 27, 2023.

SARAH WATSON

Explosions toppled the remaining old I-74 bridge towers and cables early the morning of Sunday, Aug. 27, 2023. Crowds of people came to watch and listen as the iconic green bridge, which stood over the Mississippi River for 88 years, came down.  

SARAH WATSON

Explosions toppled the remaining old I-74 bridge towers and cables early the morning of Sunday, Aug. 27, 2023. Crowds of people came to watch and listen as the iconic green bridge, which stood over the river for 88 years, came down. 

SARAH WATSON

Explosions toppled the remaining old I-74 bridge towers and cables early the morning of Sunday, Aug. 27, 2023. Crowds of people came to watch and listen as the iconic green bridge, which stood over the Mississippi River for 88 years, came down.  

SARAH WATSON

Explosions toppled the remaining old I-74 bridge towers and cables early the morning of Sunday, Aug. 27, 2023. Crowds of people came to watch and listen as the iconic green bridge, which stood over the Mississippi River for 88 years, came down.  

SARAH WATSON

Explosions toppled the remaining old I-74 bridge towers and cables early the morning of Sunday, Aug. 27, 2023. Crowds of people came to watch and listen as the iconic green bridge, which stood over the Mississippi River for 88 years, came down.  

SARAH WATSON

Mandy Stradt, of Davenport, watches with her family as explosions toppled the remaining old I-74 bridge towers and cables early the morning of Sunday, Aug. 27, 2023. Crowds of people came to watch and listen as the iconic green bridge, which stood over the Mississippi River for 88 years, came down.  

SARAH WATSON

Addison Stradt, 9, of Davenport, watches with her family as explosions toppled the remaining old I-74 bridge towers and cables early the morning of Sunday, Aug. 27, 2023. Crowds of people came to watch and listen as the iconic green bridge, over the river for the past 88 years, cam down. 

SARAH WATSON

Landon Stradt, 6, watches with his family as explosions toppled the remaining old I-74 bridge towers and cables early the morning of Sunday, Aug. 27, 2023. Crowds of people came to watch and listen as the iconic green bridge, which stood over the river for 88 years, came down. 

SARAH WATSON

A spectator checks her phone footage of the explosions that toppled the remaining old I-74 bridge towers and cables early the morning of Sunday, Aug. 27, 2023. Crowds of people came to watch and listen as the iconic green bridge, which stood over the river for 88 years, came down. 

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