It’s been a while since we checked in on the Virgin River Bridge No. 6 rehabilitation project that’s happening up in the far northwestern corner of the state, but as you can see crews have kept busy…

In the slideshow above, you’ll notice a few falling rocks, but don’t worry – that was all planned! In addition to the ongoing construction, crews worked recently to clear rocks within the work zone. The rockfall containment required some traffic breaks through last week.

You’ll also see some photos of the bridge deck demo.

If it looks a little different from other demolitions we’ve featured in the past, that’s because this bridge sits over the Virgin River and many precautions are being taken to protect the area below. We have video with many more details coming your way soon. Until then, check out our previous posts and project photos. 

What drivers should know
The $27 million rehabilitation of Virgin River Bridge No. 6 began in March 2014, and is anticipated to be completed in 2016. This significant project includes the replacement of the bridge’s superstructure (girders, deck and railings), as well as widening the roadway through the narrow passage of the gorge.

Drivers should allow for up to 15 minutes extra travel time during construction, weekdays from 6 a.m. to 6 p.m. Additional delay time may occur on weekends due to heavier traffic volume and special events. The busiest travel times through the Gorge are Friday through Sundays. With limited alternate routes due to the remote location of the I-15 Virgin River Gorge corridor, ADOT urges drivers to plan ahead and allow extra travel time.

Earlier this month, when we gave you a quick update on the Virgin River Bridge No. 6 rehabilitation project, we promised a video to showcase all the progress being made...

Today, as you can see above, we’re keeping our word!

Driving through during construction

If you’ve driven on I-15 through the project area, tucked away in the far northwestern corner of the state, you know it is a busy corridor, something that ADOT takes into careful consideration when working a project like this.

“We can’t just tear the bridge down and expect interstate traffic to take local roads,” says ADOT Senior Resident Engineer Steve Monroe in the video. “If you take out any part of that section of Interstate 15, it’s a really long way around.”

Monroe continues by explaining what crews are working on at the moment…

“Right now, they’re working on putting in the support columns,” he says. “Once they have that done, both north- and southbound will be sharing one half of the bridge – one lane in each direction. Then the half that’s open will get removed. Then they’ll replace that with a wider section that goes onto the new support columns that we just built. Then, we’ll put traffic all on the new side of the bridge and go demo out the old half of the bridge.”

More about the project

Work on this extensive rehabilitation project started in March and is expected to take up to two years to complete. Located about 20 miles south of St. George, Utah, the $27 million project includes the replacement of the bridge’s superstructure (girders, deck and railings), as well as widening the roadway through the narrow passage of the scenic Virgin River Gorge.

One more thing…

When you watch the video, you might notice that Resident Engineer Adam Carreon says, “Bridge 6 is functionally obsolete and structurally deficient and needs to be replaced to adequately handle current and future traffic loads.”

Don’t let those terms take you aback. As we explain in this blog post, these classifications do not mean that a bridge is unsafe. Structurally deficient can mean that a component of the bridge needs rehabilitation. Functionally obsolete is a term often used when a bridge has sub-standard geometric features, such as narrow lanes or shoulders or inadequate clearance.

You can also revisit some of our previous posts and check out our I-15 photos on Flickr.

There’s a lot of work happening up in the far northwestern corner of our state.

Right now, crews are busy with the Virgin River Bridge No. 6 rehabilitation project, located approximately 20 miles south of St. George, Utah.

The project includes the replacement of the bridge’s superstructure (girders, deck and railings), as well as widening the roadway through the narrow passage of the scenic Virgin River Gorge.

As you can see in the photos above, the focus currently is on constructing the bridge’s substructure, which includes the pier columns, foundation and abutments.

We’ve got a video coming up soon that’ll show even more of the project’s progress. Until then, you can learn about the project and get schedule details on the project or you can revisit some of our previous blog posts.

A call for public comments

We also want to let you know that ADOT and the Federal Highway Administration are seeking public comments on a proposed rehabilitation of Virgin River Bridge No. 1.

The $33 million project on Virgin River Bridge No. 1, approximately five miles east of Littlefield, will include the replacement of the bridge’s superstructure (girders, deck and railings), as well as widening the roadway through the narrow passage of the environmentally sensitive area of the scenic Virgin River Gorge.

As part of the National Environmental Policy Act, the Federal Highway Administration and ADOT are beginning work on an Environmental Assessment, which will evaluate potential environmental and socioeconomic impacts. Essential to identifying the best program of solutions is the participation and feedback from individuals who travel along the I-15 corridor or live in the area.

We have some good news for drivers who use the I-15 corridor in the far northwest corner of the state…

ADOT has just finished a series of bridge rehabilitation projects through the Virgin River Gorge and lifted several traffic restrictions in the area.

The $2.8 million project started in January and included upgrading the southbound bridge surfaces, girder repairs and other related work on Virgin River Bridge No. 2 (milepost 13), Bridge No. 3 (milepost 13) and Bridge No. 7 (milepost 22).

While the completion of work on these three bridges will ease traffic restrictions, motorists should be aware that construction in the area is not completely finished. A work zone will remain in place through 2016 for the reconstruction of Virgin River Bridge No. 6 (milepost 16), approximately 20 miles south of St. George, Utah.

If you’ve been following the progress along with us here on the ADOT Blog, you know that in April ADOT started an extensive rehabilitation project on Virgin River Bridge No. 6, which includes replacing the bridge’s superstructure (girders, deck and railings), as well as widening the roadway through the narrow Virgin River Gorge.

Recently, ADOT started work that will eventually serve as the foundation of the new bridge. The $27 million project is the only active project on Arizona’s 29-mile-long portion of I-15, which directly connects Nevada and Utah and is a heavily-traveled commercial and economic corridor linking southern California with the Rocky Mountain region.

What drivers should know

With limited alternate routes due to the remote location of the I-15 Virgin River Gorge corridor, ADOT urges drivers traveling between Mesquite, Nevada, and St. George, Utah, to plan ahead, allow extra travel time, slow down and drive carefully through the Virgin River Bridge No. 6 work zone. I-15 is narrowed to one lane in each direction at the bridge project and delays are possible.

ADOT works to inform the public about planned highway restrictions. Unscheduled restrictions or closures may occur. To stay up-to-date with the latest highway conditions around the state, visit the ADOT Traveler Information Center at az511.gov or call 511; outside Arizona, dial 1-888-411-ROAD (7623).

For more information about these projects visit our website or check out our previous blog posts.

We have a couple of new terms for you today and they both have to do with concrete...

First up is hydrodemolition. Simply put, it’s a method that uses a high-pressure stream of water to remove concrete, or other types of surfaces.

David Sikes, a resident engineer in ADOT’s Flagstaff District, explains in the video above that using the hydrodemolition tool is much more efficient than other methods for removing concrete.

“We get this machine that’s got about an 8-foot-wide head with nozzles on it that puts out the high-pressure water and we can take off the surface concrete fairly quickly,” Sikes says in the video. “If we had to do it with chipping hammers, it would probably double the work time.”

Besides being efficient, Hydrodemolition can allow crews to control the depth of the cut they’re making (the machine’s pressure can be adjusted and its nozzles can be controlled). Hydrodemolition also helps control any dust – crews use a vacuum hose to suction water and debris as they go along.

The next term we’d like to define is Microsilica Modified Concrete (MMC).

MMC is a type of concrete that’s mixed with microsilica, which according to the FHWA, “is a byproduct of the reduction of high-purity quartz with coal in electric furnaces in the production of silicon and ferrosilicon alloys.” MMC has plastic fibers in the mix, too, as shown in the video above.

The result is a dense and durable concrete that is very appropriate for bridge decks like I-15 Virgin River Bridges 3 and 7, Sikes says.

“Trucks traveling south on I-15 carry salt-laden slush from roadways to the north. As the air temperature warms, the salt mixture drops off of the trucks onto the bridge decks.  If the salt is able to penetrate the concrete down to the rebar, the rebar will corrode, causing the concrete surface to pop off,” he said. “MMC is a very dense concrete that will resist the penetration of the salt mixture. We should have a durable bridge deck for a number of years.”

Transportation Defined is a series of explanatory blog posts designed to define the things you see on your everyday commute. Let us know if there's something you'd like to see explained ... leave a comment here on the blog or over on our Facebook page!