A “train of Cat scrapers” led the way as Whaley & Sons, Sevierville, TN, performed site work for a new runway apron expansion at McGhee Tyson Airport, Knoxville, TN.
Eleven Cat 631 scrapers moved the earth and dug the 300-ft. (91 m) wide and 65-ft. (20 m) deep trench, while Komatsu dozers and excavators helped lay two lines of 108-in. (274.3 cm) stormwater pipe.
“This was the biggest pipe job in the region. We ended moving approximately 1 million cubic yards of earth. We were laying a double line of 108-inch concrete pipe that stretched 1,700 feet,” said Clint Fleming, Whaley & Sons’ vice president of construction.
“We moved 230,000 yards just to lay out the pipe. We went down to 65 feet. Then, we under cut another three feet. We came back and filled the three feet in with shot rock and 57 stone and then laid the pipe down,” explained Fleming.
He said the rainy weather prompted the use of the shotrock.
“Going down the extra three feet and then filling that up saved us a lot of time. The winter months were coming and we did not want to work in the mud. Putting down the stone enabled us to work in dry conditions. We had cranes and tractor-trailers at the bottom. We did not want them mired in any mud,” said Fleming. “It cost the customer a little bit more money, but we finished ahead of schedule. And, since time is money, I guess we ended up saving them money too.”
Fleming said the pan-scrapers were lined up “like a train,” each one of them cutting away a foot of earth as they coursed through the trench.
“Nothing moves dirt faster than a scraper. We had them moving, one right after another. Later, after we had laid the stormwater pipe, we panned the dirt and just filled the trench back up,” said Fleming.
Even though the trench was 65 ft. (19.8 m) deep, there was no need for trench boxes or other support because it was not a vertical cut. He used a 1.5 to 1 slope. However, a trench box was used on the 18-ft. (5.5 m) deep trench dug by the Komatsus to lay the sewer pipe.
Whaley & Sons, a medium-sized contractor, ordinarily specializes in highway construction. For example, they have done a lot of work on I-40. Despite the wet weather, most of the 160 people employed by Whaley & Sons have been working steadily.
“Right now, we have 14 jobs under contract. We try to keep a few rock jobs where there is not much dirt, so we can be working in the rain. Rock jobs keep us out of the mud. We try to do that type of work in the winter and in the wet weather. Another good job in wet weather is pipe. You can lay pipe when it is wet,” he said.
Traditional site prep work, however, does run into slowdowns when it rains. Not very far from the airport job, Whaley & Sons has been preparing ground for a warehouse expansion.
“There is nothing really hard about this job, except you can’t work as well in the rain and the mud. The weather — the rain has just been terrible. It would normally have taken us about six to seven months to do this type of job. Now, it looks like it is going to run a little bit over a year,” said Fleming, “We’ve been lucky to work two, maybe three days a week because of the rain.”
Whaley & Sons is doing site work for H.T. Hackney, a food distributor, which is setting up a 9-acre (3.6 ha) facility on a 66-acre (26.7 ha) plot of land outside of Knoxville.
“We’re doing typical site work — cut and filling, grading and laying stormwater,” said Fleming.
He estimates crews will move approximately 600,000 cu. yd. (459,000 cu m) of earth, using most of it as fill. Workers will be laying 7,000 lineal ft. (2134 m) of 72-in. (183 cm) concrete pipe.
Fleming said the company is using a large number of Komatsus from Power Equipment, including three dozers — a D375 , a D-61 and a D-65, as well as four trackhoes — two PC300s and two PC400s.
“Lin Anderson and the folks at Power Equipment are great. The Komatsu is a good machine. They make good dozers and trackhoes. We have 10 of their excavators. We never have a problem with them. They are easy to operate and maintenance is at a minimum,” said Fleming.
There is a lot of iron on the 66-acre site. In addition to the Komatsus, Fleming said his crew also is using eight Cat 631 scrapers, a Cat D-9 dozer, two Cat 815 compactors, an Ingersoll-Rand 115 compactor, a Cat 12H grader, a Cat 16D grader, two 416 Cat rubber tire backhoes and four Cat 250 articulated haul trucks.
Fleming said his crew would be doing the site prep for three large parking lots, the building pad, a road as well as a 2.5-acre (1 ha), 8-ft. (2.4 m) deep retention pond.