Mile High Shift complete, demolition of I-70 viaduct underway

DENVER — As part of the Colorado Department of Transportation’s Central 70 Project, the much-anticipated Mile High Shift took place this morning as Interstate 70 reopened between I-270 and Washington Street. Crews worked around the clock this past weekend to prepare for traffic to enter the new lowered section of I-70 between Colorado and Brighton boulevards for the first time. All six lanes of I-70 traffic were moved from the existing viaduct onto the future westbound lanes of I-70, making way for demolition of the 57-year-old viaduct and the build-out of the future eastbound lanes of I-70 and 46th South Avenue.

“We are incredibly proud of everything our crews have accomplished since groundbreaking in August 2018 and over the weekend to make this historical shift happen,” said CDOT Project Director Bob Hays. “We want to thank motorists for their patience during this closure as we know that detouring around your normal route can be inconvenient, but we were able to perform critical work all while keeping motorists safe. We ask now that motorists leave earlier than they normally do if they are planning on driving through this section of I-70. It will take time for folks to get acclimated to their new surroundings over the next week or two and there will no doubt be slow-downs.”

In addition to the switch onto the new lanes of I-70, here is a list of the ramp realignments as of today: 

Westbound I-70

• Colorado off-ramp - open
• Colorado on-ramp - open
• Steele off-ramp – closed permanently
• Steele on-ramp – open
• York on-ramp – closed permanently
• Brighton off-ramp – open
• Brighton on-ramp - open 

Eastbound I-70

• Brighton off-ramp - open
• Brighton on-ramp - open
• York off-ramp – closed permanently
• Steele off-ramp - closed temporarily
• Steele on-ramp – closed permanently
• Colorado off-ramp - open
• Colorado on-ramp – open

Traffic flowing in its new, temporary configuration on I-70 west of Colorado Boulevard going underneath the new cover top (Courtesy: Colorado Department of Transportation)

Now that traffic is in the new lowered section, it is time to finish demolishing the old I-70 viaduct and build out the eastbound lanes. On Saturday, May 22, crews began demolishing I-70 just east of Brighton and just west of Colorado boulevards. For the past 57 years, this viaduct has stood as a connector for eastbound and westbound traffic along I-70; however, it was no longer able to accommodate the nearly 200,000 motorists who travel this stretch of roadway today nor the projected growth in the years to come. 

“The viaduct demolition represents Denver’s incredible growth over the past six decades,” said Hays. “This demolition is a major transportation milestone, but also a moment to pause and reflect on how the Denver metro area has evolved since the 1960s. We’re excited to start this next phase and continue to help contribute to the state’s future.”

Once demolished, crews can begin building the new eastbound lanes of I-70 in the lowered section (between Brighton and Colorado boulevards). The demolition is anticipated to take approximately five months. 

Traffic Impacts: 

The viaduct will be demolished in sections primarily during daytime hours using excavators, crushers and concrete grinders. Depending on the section being demolished, local street closures and some overnight I-70 lane and ramp closures will be required. The demolition will occur over closed roadways with no traffic nor pedestrians moving through the area. Check out the viaduct webpage to learn more about the sequencing of demolition and associated traffic impacts. 

Moving traffic onto the new lowered section of I-70 reduces any traffic impacts to the interstate during viaduct demolition. Three lanes of traffic in each direction on I-70 will continue to be open during peak travel hours. 

Environmental Protections: 

During the viaduct demolition, several mitigations will be in place to protect the traveling public, adjacent businesses and the local residents from noise, dust and debris. A majority of the viaduct will be taken down during daytime hours to reduce nightly impacts to local neighbors. 

“Minimizing the demolition’s environmental impacts and being good neighbors to nearby residents and businesses are our priorities,” said Hays. “Our commitment to “clean” construction still stands as we begin the viaduct demolition, and we are taking extensive measures to ensure folks are safe and healthy throughout construction.”

To protect adjacent structures, netting and sound curtains will be installed along the property line to protect falling debris from damaging nearby commercial or residential properties. Crews will also be utilizing the Project’s air monitors to measure dust to ensure impacts are within an allowable threshold. Crews will also use personal air monitors to ensure the air quality meets OSHA standards. Water will be used to keep the materials damp to prevent additional dust, and crews will be verifying noise levels remain within allowable limits with noise monitors. 

Although not required through variances with the Public Health and Environment Department or the Central 70 Project Agreement, Central 70’s Developer, Kiewit Meridiam Partners, has committed to going above and beyond by installing various vibration monitors between Brighton and Colorado boulevards to ensure demolition activities do not go beyond baseline vibration thresholds.  The demolition will also implement a contaminated material removal process to properly break down and dispose of materials that cannot be reused elsewhere. Take a look at our Will and Will Not graphic to learn more about what to expect during demolition. 

Viaduct demolition activities will be similar to that of the recent Washington Department of Transportation project that worked to remove the Alaskan Way Viaduct. To see how crews managed to safely demolish the viaduct and protect nearby buildings visit Alaskan Way Viaduct demolition: Goodbye Seneca Street ramp.  Kiewit Corporation was the contractor on the project.  

Misting cannons in use on Saturday, May 22, 2021, to wet dust to prevent it from spreading throughout the air during the demolition of the I-70 viaduct (Courtesy: Colorado Department of Transportation)

About the Central 70 Project

The Central 70 Project will reconstruct a 10-mile stretch of I-70, add one new Express Lane in each direction, remove the aging 57-year-old viaduct and lower the interstate between Brighton and Colorado boulevards. More information on the Project, including a list of the Project’s community commitments, are available at central70.codot.gov.

Stay Informed

• Text Alerts - Text Central70 to 77948
• Email Updates - Sign up for Project updates at c70.codot.gov 
• Website - c70.codot.gov - Traffic Impacts page 
• Watch progress on the webcam