By: Bill Wilson
When you work off the land it’s the stress that can keep you from eating for days.
Kiewit Infrastructure West Co. oftentimes had to make the best of what was around it during the North Prince of Wales Road from Deweyville Trailhead to Neck Lake Road project. Located within the Tongass National Forest on Alaska’s Prince of Wales Island, the prime contractor, along with designer PND Engineers, the Federal Highway Administration and the Western Federal Lands Highway Division, worked the elements to transform 11 miles of single-lane gravel road into two, 11-ft paved lanes with guardrails. Miles away from any sign of civilization, tension was higher than the levels found on a more typical road construction project, but the success rate also was better than the norm, making the Deweyville Trailhead to Neck Lake Road project No. 1 on the Roads & Bridges’ 2015 Top 10 Roads list.
“Being fairly remote out there was one of the challenges,” Brad Halvorson, project sponsor for Kiewit Infrastructure West Co., told Roads & Bridges. “A great deal of planning went into how we were going to deal with it.”
Rockin’ it
North Prince of Wales Road was originally put in place in the early 1900s to handle the logging industry, but these days it’s a vital link for those living in the region, even though the population numbers are light. A total of 6,000 people live on the island, the fourth largest in the U.S., with Craig representing the largest town at 1,000. The jobsite, however, was located on the northern end, where the most people you will find in one area is about 70.
Because the location was remote, any material found near or around the project was gold. Limestone, needed for embankment and to help fill the 8-in.-thick sub-base, was everywhere, as long as you could find it. Reaching it was a whole other issue. Large quantities of peat waste material covered the area, and the limestone rock. An advanced geotechnical investigation was implemented to sample, test and scientifically predict where to find material. An excavator was used for test digs, and a peat probe, a smooth stick that was pushed down until it hit a hard surface, also came in handy.
“You had to excavate out the waste and find the bottom, and once you found the bottom you could verify and see what quantities of rock you were going to either produce or what you needed to use to fill back in and see what the differences were for what the original assumed design depth was in that area,” said Halvorson.
Once you pulled the rock from the earth, another challenge surfaced. Because the limestone is extremely undulating and uneven, peat material would sit in these miniature valleys. Add some rain (the area receives about 100 in. of rainfall a year) and you are left with a sloppy mass of rock and mud. The rock had to be very clean before it was broken up and used for the embankment and sub-base, and attempts to use an excavator bucket failed.
“The teeth would always get ripped off,” said Halvorson.
Tires of articulated trucks also were chewed up after an extensive amount of hauling, which gave the crew an idea. The old tires were gripped in between the teeth and thumb of an excavator bucket, creating a large squeegee that was able to get into the hard-to-reach areas on the rock and remove the muck.
Heavy rainfall made the peat removal a chore even when you were not dealing with limestone. The peat would absorb the moisture, turning it into more of a liquid as the excavator operators tried to remove it, so they were getting smaller and smaller loads as the precipitation continued. Kiewit Infrastructure West Co. also had to build dikes around the peat waste area.
The project required 925,000 cu yd of excavation of both peat waste material and rock used for the embankment/sub-base, and crews drilled and blasted a total of 506,000 cu yd of rock for the job. The man-hours required also piled up, as Kiewit worked two 10-hour shifts six, sometimes seven days a week to produce enough road material.
A 30-day fish window also exhausted the time sheet, as Kiewit had to adhere to strict drainage requirements that called for the installation of 8,500 linear ft of drain pipe and 13 fish passage structures. Since the work had to be completed in a single month, double shifts again came into play.
“There were two different fish windows we had on the project and it was due to the species of salmon that used those streams,” said Halvorson.
Even though traffic was relatively light, crews had to construct the fish passages one-half at a time. Starting with super sacks—bags filled with gravel—a dam was created in the existing stream right above where the inlet was for the new culvert. If the stream was not diverted, a special pump was used, one with inlet protection so as to not suck up any fish. Excavation would then take place and half of the passage would be installed. Fill was placed on the new pipe and a diversion road was created for traffic before the other half of the culvert was put into place.
“These pipes had fully welded baffles, so that helped some of the issues that [Alaska] Fish & Game had before with bolt-on baffles where the water would run in between the baffle and bottom of the pipe because it is not a full seal,” Dan Petersen, construction manager for Kiewit Infrastructure West Co., told Roads & Bridges.
Once the fish passage was set another innovation rose to the occasion. In order to place streambed material in the pipe, a small hand conveyor belt system was used.
“We were able to use a mini excavator to put the streambed material on this conveyor,” said Petersen, “and we had guys inside there shoveling and smoothing things out, building this Zen garden of a fish passage.”
Material was mined in spots throughout the jobsite, and a 6-in. minus round, cobble-style rock was used for the streambed. A musk egg mud material was used to fill in between the rocks, and 16-in. boulders were strategically placed to create resting channels for the salmon as they migrate upstream.
Roadtec RP-195E and Blaw-Knox PF-5510 asphalt pavers were used to lay 3 in. of asphalt surface course. The project also called for a 4 in. base course. The Superpave mix contained a PG 58-28 binder and ½-in. nominal max aggregate. An Ingersoll Rand DD-130 vibratory steel double-drum served as a breakdown roller, while a Caterpillar 534DX and an Ingersoll Rand DD-138 served as the finish rollers.
Two 50-ft bulb T girder concrete bridges with spread footings also were constructed. A concrete batch plant was set up on-site, and the only time bridge erection became an issue was when the temperatures dipped, which happened as early as November. Stockpiles were layered with old military parachutes, and heaters would blow into the covering.
Talking, birds
Great care went into protecting the species at ground level, and at tree-branch level too. The Migratory Bird Treaty Act required the contractor to train five individuals to be master birders. Before any clearing could take place the trees in the cutting zone were checked for bird nests.
Because there were no cell-phone towers or Internet access in the region a communications system had to be assembled on-site. A satellite dish armed with a generator was installed, and satellite phones and radios were used to talk on the job. R&B
About The Author: Wilson is editorial director of Roads & Bridges
