I-40 Rockslide: Helicopter Used to Speed Up Process

UPDATE WEDNESDAY, February 3, 2010 at 3:30 PM

RALEIGH – Working in tandem with a helicopter, crews with Janod Construction Inc. today installed dozens of new rock bolts into the mountainside where the I-40 rockslide occurred.

Crews aim to install as many as 50 to 60 of the rock bolts needed at the site by the end of the day. That would be the largest number achieved in one day so far on the project.

In trip after trip, the helicopter ferried a type of bolt known as a cable strand anchor from the ground to a crew working on the mountainside. A cable strand anchor is made up of a bundle of wire cables consisting of two, three or four strands of steel cable. This type is flexible and can be used in holes extending from 60 feet to 115 feet into the groun

As the helicopter hovers over the slope, workers grab one end of the cable strand and begin inserting it into the hole. As the helicopter lowers itself closer to the slope, workers feed the rest into the hole and the other end is released. The chopper returns to the ground and starts the process all over again.

Using the helicopter speeds up the work, reducing installation time to as little as five minutes. When the crew has to carry the cable strands up the mountainside, the whole process can take up to an hour.

In all, 590 bolts will be used to shore up the mountainside. A video explaining the plan to stabilize the rock mass on the mountain has been posted on NCDOT’s YouTube Channel at http://www.youtube.com/NCDOTcommunications. Click on the “Shoring Up the Mountainside Where I-40 Rockslide Occurred” video.

A night shift is planned and crews will continue to drill holes where bolts will be installed later. On Thursday, crews plan to grout the bolts that were put in today to cement them into place.

This section of Interstate 40 near the Tennessee border has been closed in both directions since the rockslide occurred Oct. 25.

NCDOT estimates that the interstate could be fully reopened sometime in March depending on weather conditions between now and then. A decision on any partial opening of the highway will be made as work progresses.

UPDATE MONDAY, February 1, 2010 at 6:24 PM
RALEIGH – As weather conditions improved today, construction crews returned to work on the mountainside where the I-40 rockslide occurred.

Crews continued drilling holes where 590 rock bolts will be installed to stabilize the mountainside. Holes are also needed for the bolts that secure wire safety nets that will be positioned in some areas of the slope.

In all, crews will drill about 11 miles of holes at the site. As of Jan. 28, they had drilled about 3.2 miles of holes.

Snow and subfreezing temperatures delayed work on the mountainside since Friday. The National Weather Service forecast an overnight low of 26 degrees and a chance of sleet and freezing rain early Tuesday morning. But a night shift still is planned and crews will work unless conditions become too risky on the steep, rocky terrain.

Plans are to install more bolts on Wednesday and a helicopter is scheduled to return then to ferry the bolts to the top of the mountain. Today and Tuesday, crews will be drilling holes, measuring and checking their depths and assembling bolts at the foot of the mountain so that they will be ready to install.

This section of Interstate 40 near the Tennessee border has been closed in both directions since the rockslide occurred Oct. 25.

Travelers still can reach Western North Carolina via I-40 from the east and I-26 to the north and south. Exits 20 and 27 on I-40 provide access to popular destinations west of Asheville. In Tennessee, exits 432 through 451 provide access to popular destinations in southeastern Tennessee.

The detour route is 53 miles longer and is an additional 45 minutes to an hour driving time. Motorists traveling on I-40 West should take Exit 53B (I-240 West) in Asheville and follow I-240 West to Exit 4A (I-26 West). Follow I-26 West (a North Carolina Scenic Highway) to I-81 South in Tennessee. Take I-81 South and follow it back to I-40 at mile marker 421. Eastbound motorists should use the reverse directions.

NCDOT reminds motorists to stay alert, follow instructions on the message boards on the highways, obey the posted speed limit, leave early and travel at non-peak times when possible. Plan ahead before driving by visiting the NCDOT Traveler Information Management System Web site at www.ncdot.gov/traffictravel/ or calling 511, the state’s free travel information line, for current travel conditions.

NCDOT also provides alerts about traffic congestion and construction work on Twitter. To access them, go to www.ncdot.gov/travel/twitter/. For daily rockslide updates, please visit the NCDOT Web site at www.ncdot.gov and click on the I-40 rockslide daily news and information section or follow work on the rockslide project on Twitter at http://twitter.com/i40_rockslide.

UPDATE Monday, January 25, 2010 at 4:49 PM
RALEIGH-A new rockslide occurred on the closed section of Interstate 40 sometime late Friday night or early Saturday morning causing rocks and loose material to cover an additional small section of the westbound lanes.

This portion of the interstate has been closed since an original rockslide occurred on October 25, 2009. There was no traffic at the time of this occurrence.

The rockslide took place at Harmon's Den Exit 7, about four miles east of the October 25th rockslide. Approximately 500 cubic yards of rock was released onto the highway, with the largest chunk being about the size of an SUV.

The rockslide was discovered on Saturday morning at 1:00 AM by a construction supervisor and the contractor working on the project to reopen the interstate's westbound lanes.

Initial assessment at the site by NCDOT engineers and geotech experts concludes that it will take two to three weeks to clean up the material on the highway. However, NCDOT reports that this new rockslide should not slow down it's scheduled reopening of the closed section of I-40 in March, depending on the weather conditions between now and then.

RALEIGH – Work on drilling holes to install rock bolts on the mountainside where the rockslide occurred has been delayed due to the extreme cold at the site.

The cold weather created unsafe working conditions for crews working on the side of the mountain. The National Weather Service forecast a high of 24 degrees on Monday and a wind chill of minus 5 degrees overnight.

Drilling was stopped at noon on Saturday due to the cold and snow at the site. The National Weather Service forecasts extreme cold and snow showers throughout the week for Clyde, which is near the site. As of Monday afternoon, the forecast calls for:

· Highs ranging from 24 degrees today to 31 degrees on Thursday;

· Overnight lows ranging from 7 degrees tonight to 17 degrees on Thursday night;

· Chance of snow showers tonight, Tuesday and then again on Thursday and Friday.

DOT engineers will decide on a day-to-day basis if work crews can safely do the drilling needed to install the rock bolts during daytime hours. No work will be scheduled this week at night.

In all, 590 rock bolts will be installed on the mountainside as crews work to shore up the mountainside so that the highway can be safely reopened.

The extreme weather conditions make:

· Footing treacherous for workers on the steep, rocking terrain especially during times of snow or ice;

· Exposure to subfreezing temperatures a safety risk to workers;

· Equipment difficult to use as hydraulic systems used to operate drills don’t work as efficiently and drills freeze to the ground, making them difficult to move.

Work crews will continue to maintain the equipment so drilling can quickly resume once weather conditions improve. Crews also are building tarp enclosures where portable heaters can provide relief to workers on the slope.

Other work is still going on, including the handling of some 1.2 million pounds of material that is arriving at the site. The material, including rods, cable strands, and bags of grout, must be approved and then transported up the slope.

The section of the interstate where the rockslide occurred has been closed since Oct. 25. Estimates are the highway could reopen sometime in March, depending on weather conditions during the winter.