J-Six

(Re)-bridging the gap: Mescal/J-Six Bridge set to open

(Re)-bridging the gap: Mescal/J-Six Bridge set to open

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(Re)-bridging the gap: Mescal/J-Six Bridge set to open

(Re)-bridging the gap: Mescal/J-Six Bridge set to open

September 19, 2011

It’s been just about six months, but today the residents of Mescal and J-Six Ranch got their bridge back and can finally say goodbye to one lengthy detour!

These two Cochise County communities had been linked together by an overpass that spanned Interstate-10. But back in March, two semi-trucks collided underneath that bridge and the resulting damage was so severe that the connection between Mescal and J-Six had to be closed for safety’s sake.

Fast-forward to today ... a brand new bridge is in place, ready to accommodate the motorists who have been forced to take the long way whenever they needed to drive between the two neighborhoods.

“For most motorists traveling I-10, this closure was an inconvenience,” says ADOT Director John Halikowski in the video above. “It meant they’d have to travel a little farther to stop for gas. But for the communities of Mescal and J-Six Ranch, the overpass closure created a heavy burden. You see, the bridge is the only road connecting Mescal and J-Six Ranch. Residents from both sides were cut off from the businesses and services they rely on.”

Normally a project like this would have taken up to two years to complete, but ADOT put this job on the fast track because of the hardship the closure caused to local residents (motorists were seeing about 14 miles added to their round trips just to get across the road, which really starts to add up after a while).

The accelerated project started with the demolition of the old, damaged bridge. ADOT was able to take advantage of a previously scheduled April 8 closure of I-10 for the demolition of the nearby Marsh Station Bridge and was able to take down the Mescal/J-Six Bridge the same night.

An expedited design timeline also helped speed things along. An abbreviated bid process that focused on contractors with a track record of building bridges under emergency circumstances kept things moving, too.

The project received $955,000 in emergency funds from the Federal Highway Administration and construction was able to get started right after Fourth of July weekend.

Work included the placement of 35 new concrete box girders atop the bridge piers. Outside support beams were also placed, but they featured attached, precast bridge barriers designed to help expedite the construction.

Amazingly, by Sept. 9, crews were already prepared to pour 150 cubic yards of concrete for the 216-foot-long bridge deck.

The concrete took 10 days to cure and you’d better believe crews didn’t let that time go to waste! They continued to work by filling gaps in the barrier wall between box girders and putting the finishing touches beneath the overpass.

The very final step taken before the bridge could open to the public included placing temporary markers along the lanes (permanent striping will be added to the roadway at a future date).

We’ve followed the progress of this project through videos and blog posts and now that the bridge is open, we hope you’ll take a look back at what it took to get here! As you can see in the video above, this bridge is important to the two communities it connects.

We at ADOT would like to thank all the residents, business operators, as well as Cochise County officials for their patience and support!

Note: This blog post was updated to reflect a revised open date for the bridge. It opened Monday afternoon, about 16 hours ahead of its Tuesday scheduled date.

Chance for tremor is slim, but bridges built to endure

Chance for tremor is slim, but bridges built to endure

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Chance for tremor is slim, but bridges built to endure

Chance for tremor is slim, but bridges built to endure

September 14, 2011

Earthquake-proofing measures are part of the plan for the new Mescal Road/J-Six Ranch Bridge, near Benson.

The recent quake near Washington, D.C. served as a reminder that the earth occasionally moves in U.S. locales outside of California.

At ADOT, we know that Arizona is not immune to seismic activity, either. While earthquakes are far from commonplace in the Grand Canyon, our engineers take nothing for granted.

Across the state, highway and interstate bridges built since the 1970s have been designed to meet or exceed standards established by the American Association of State Highway and Transportation Officials. Older bridges have been retrofitted to help them hold up better against earthquakes.

Most of Arizona is believed to have little risk of earthquake, but certain areas – Coconino, Yuma and Cochise counties – are known to be vulnerable to seismic movement.

So when the ADOT Bridge Group set about designing the new Mescal Road/J-Six Ranch Bridge near Benson, earthquake-proofing measures were part of the plan.

That starts with enhanced reinforcement of the structure, including columns and foundation.

Each bridge is individually designed to hold up in the conditions unique to its surroundings. For instance, a location with loose sand or silt gets a deeper foundation including drilled shafts or piles.

Each bridge is built in a footprint wide enough to allow horizontal movement of the bridge. Those in potentially vulnerable areas – such as Mescal/J-Six are constructed with anchor bolts incorporated into the girders that allow controlled movement.

In the photo above, you can see the anchor bolts protruding out of the pier cap closest to the front of the picture. There is a hole at the end of each girder that goes through the anchor bolts. These bolts will allow for some movement of the girders during a seismic event, but not very much (a couple of inches laterally and less than that vertically).

You can also see the vertical fixed restrainers on the next pier cap in the photo. Those are basically cable ties that will fix the girders to that pier cap. The girders are placed on either side of the line of fixed restrainers and then a reinforced concrete diaphragm is poured in the gap, which completely ties the girders and the pier cap together. These fixed restrainers allow for no movement of the girders. The pier is permanently anchored and the rest are on the earthquake restrainers. The pier that doesn't move anchors the bridge ... the rest move and disperse any seismic activity.

Allowing for slight, limited movement during an earthquake (even a little one), means the bridges stay sound.

Tiny camera captures bird’s eye view of girder installation

Tiny camera captures bird’s eye view of girder installation

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Tiny camera captures bird’s eye view of girder installation

Tiny camera captures bird’s eye view of girder installation

August 29, 2011

If you’ve been following along in the blog, you know that we’ve been chronicling ADOT’s reconstruction of the Mescal/J-Six bridge in southern Arizona since it was severely damaged when two semi trucks collided underneath it back in March. Completion of the fast-tracked bridge reconstruction is slated for later this month.

Last week, crews installed 35,000-50,000 pound girders and our video team wanted to explore a creative way to take you behind the scenes of what goes into placing a 25-ton piece of concrete.

To get the perfect shot, they looked to a GoPro® Hero. GoPros are tiny (1.6” x 2.4” x 1.2”, 3.3 oz) HD cameras that let photographers get some incredible shots they never would have been able to otherwise.

Here's a shot of the GoPro in action. The inset photo gives you an idea of how small the camera really is.

Conditions weren’t exactly ideal (check out our Facebook page for pictures of the tarantula and other creepy crawlers that joined their shoot and the extreme weather that loomed in the distance), but they couldn’t miss a chance to secure a GoPro to one of those massive girders! (You might want to sit down before watching this one…it may make you a little dizzy.)

A new look at memorable I-10 bridge demos

A new look at memorable I-10 bridge demos

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A new look at memorable I-10 bridge demos

A new look at memorable I-10 bridge demos

August 19, 2011

Last week we gave you an update on how the new Mescal/J-Six bridge is coming along...

You might also remember that the night the damaged bridge was taken down, the old Marsh Station bridge was also demolished just a few miles away. It was a huge project that required completely shutting down I-10 for the night.

Check out the video above for a quick look at the work involved with tearing down two bridges in less than 10 hours.

Repairs to damaged bridge set to finish by fall

Repairs to damaged bridge set to finish by fall

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Repairs to damaged bridge set to finish by fall

Repairs to damaged bridge set to finish by fall

August 10, 2011

Crews put the finishing touches on the shoring that will support the pier cap on the newly reconstructed columns. The old columns were severely damaged by fire on March 15.

The new Mescal Road/J-Six interchange is taking shape!

The Cochise County bridge will soon reunite two communities that were unexpectedly disconnected after trucks collided beneath the old overpass in March.

After a fast-paced pre-construction process, work to rebuild the bridge began in early July. Just one month in, the hard-working crews from Vastco Inc. have constructed the bridge columns next to the eastbound lanes and erected shoring on those new columns to pour a new pier cap, and completed the pier caps atop the other columns that survived the fiery crash.

All this is in preparation for the setting of 35 new bridge girders, which are scheduled to make their appearance on the scene later this month!

pier-one-columns

Rebar that will tie into a new pier cap pokes skyward from four new columns next to the eastbound lanes of I-10 at the project to replace the overpass.

Folks driving past this project on I-10 can expect two overnight closures – with traffic exiting on one side of the project and re-entering the interstate on the other side – while those girders are put into place.

Before you know it, a new bridge will mark the return of the short drive residents of Mescal and J-Six Ranch have missed these past several months.

ADOT truly appreciates the support and patience of these communities and looks forward to celebrating the reopening of the Mescal-J-Six bridge this fall!

ADOT to begin work on replacement bridge soon

ADOT to begin work on replacement bridge soon

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ADOT to begin work on replacement bridge soon

ADOT to begin work on replacement bridge soon

June 13, 2011

Talk about a quick turnaround … it’s been just three months since a fiery crash destroyed the Mescal Road/J-Six Ranch Road bridge in Cochise County and already ADOT has approved a contract to rebuild and reopen the bridge this fall.

Considering the process can normally take up to two years, it is clear this project is critical to the nearby communities.

You might remember that the bridge suffered heavy damage back on March 15 after two semi-trucks collided underneath it. The damage from the resulting fire was so severe that the bridge was demolished by ADOT a few weeks later on April 8.

But, with the bridge gone, so is the link between the communities of Mescal and J-Six Ranch, and that is why the replacement project is on a fast track.

In fact, construction is expected to begin early next month at the site located on I-10 at milepost 297, west of Benson.

The project includes replacement of four columns, retrofit of abutments, installation of new precast concrete girders, construction of the concrete roadway, placement of approach slabs, painting of the existing and new portion of the bridge, pavement marking and other related work.

Federal Highway Administration emergency relief funds, a shortened time frame for designing the replacement bridge and a quick construction bid process all have helped move the project ahead at a rapid pace.

Drivers in the area should know that detours have been in place since March 15, when fire damage to the concrete piers and steel girders required closure of the bridge, which was originally built in 1958. The adjacent pedestrian bridge was not damaged by the fire.

How to tear down two bridges in 10 hours or less

How to tear down two bridges in 10 hours or less

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How to tear down two bridges in 10 hours or less

How to tear down two bridges in 10 hours or less

April 15, 2011

In just 10 hours this past weekend, two bridges in southern Arizona were demolished in order to make way for something new.

All it took was some good planning, plenty of patience from motorists, a few enormous machines, and a ton of work by crews on the sites.

A little bit of background …

In November of 2009, ADOT began work on the I-10 Marsh Station Traffic Interchange in Southern Arizona -- a $10 million American Recovery and Reinvestment Act project that includes the extension of Marsh Station Road, drainage improvements, and the construction of a new traffic interchange to accommodate commercial truck traffic.

As it stood, the old Marsh Station Bridge had a clearance of 15 feet -- too low for most commercial trucks to clear. To avoid the bridge, trucks taller than 15 feet have had to maneuver a winding, two-lane, 67-mile detour.

(Note: Not until a nearby Union Pacific Railroad bridge is removed later this year, will most trucks be free to ditch the detour and safely pass through the new traffic interchange.)

But first things first, the old Marsh Station Bridge needed to come down. The only way to secure the work site and ensure the safety of both ADOT crews and the travelling public, however, was to close Interstate-10...forcing all local and interstate traffic into that same 67-mile detour!

After a lot of planning -- being careful to avoid Spring Breaks and other heavy-travel holidays -- ADOT set a date (April 8) and made arrangements to bring down the bridge, clean up the debris, and reopen the interstate, all in a 10-hour, overnight window.

The unexpected...

About three weeks before the demolition was set to occur, on March 15, two semi trucks collided under the overpass at the Mescal Road/J-Six Ranch Road Bridge about eight miles down the road from the from the old Marsh Station Bridge. The bridge was badly damaged from the resulting fire and would have to be replaced.

The task...

Since the interstate was already going to be closed, was it possible to safely get another bridge down in the same 10-hour window? Sure it was, and here’s what it took…

Breakdown by the numbers:

250:
The approximate number of tons of dirt that went down on the roadway below the bridges to act as a cushion for what the crews tore down.

1,480,000:
The approximate number of pounds of concrete removed during the demolition of both bridges. If you need a way to visualize just how much heft 740 tons is, it’s equal to the weight of about 120 adult male African elephants.

112,000 and 232,000:
The approximate pounds of rebar (112,000) and steel (232,000) that were removed during the take down of both bridges.

6:
The number of excavators used on both projects. Two excavators with scissor-like attachments worked on the Marsh Station Bridge demolition. Four excavators (two with the scissor-like attachments and two with hydraulic hammers) worked to bring down the Mescal Road Bridge.

45:
The number of seconds it takes us to show the Marsh Station demolition in this time-lapse video!