An excavator buries its boom 16-feet deep into a marsh, pulling out a bucket full of wet, black glop and drops it into a waiting haul truck for transport off site. At the same time, another haul truck brings a load of sand to the site, and dumps it so that a dozer can push the sand into the space where thick muck had been minutes earlier.
In this way, the marsh truck crew for H. James & Sons, Inc., Fennimore, Wis., excavates a peat bog as part of the construction of the Burlington Bypass.
The 5.7-mile bypass is being constructed east of Burlington, Wis., from the Highway 36/83 interchange northeast of the city to Highway 83 south of Burlington.
H. James & Sons is the grading contractor for the first contract of the Wisconsin Department of Transportation (WisDOT) project.
In addition to the mainline grading, work includes reconstructing portions of Highway 142, Highway 11 and County Highway A, as well as constructing the Highway 36/83 interchange. Construction of two bridges and two box culverts is also part of the contract.
A total of approximately 3.2 million yards of material is being excavated.
Clearing and grubbing started in mid-March, with grading beginning in April.
Excavation includes approximately 600,000 yards of marsh. An estimated 300,000 yards of marsh excavation is concentrated in one marsh, which is 10 feet to 28 feet deep.
The crew from H. James & Sons began excavation of that marsh in September.
"It's too early to tell if the marsh quantity will run over, if half of it's in one area. That one will make or break the whole job, as far as marsh quantity," said Randy Henkel, superintendent for H. James & Sons.
Many of the marshes being excavated for construction of the bypass have been deeper than anticipated.
"A couple of the marshes were supposed to be 6 feet to 8 feet deep, and they were 13 feet to 18 feet. The County A marsh was supposed to 13 feet or 14 feet deep, and it was 28 feet deep," Henkel said.
When excavating a marsh, the crew goes down until it hits sand and gravel or hard clay.
The shallowest marsh excavations have been 6 feet deep, while the deepest was 28 feet.
One 600-foot wide marsh had 3 feet of water on top of the marsh, which was 16 feet deep.
"That was like going through a pond," Henkel said. "That was the worst marsh we had to go through on this project."
When the crew finished excavating that marsh, the excavator used on the job was flushed and had its hydraulic oil changed before returning to work because water had seeped into the hydraulic oil.
When excavators are working in the marsh, the equipment is greased three times a day to keep the joints properly lubricated.
"The water just chews it up, so we grease multiple times a day," said Henkel.
The marsh truck crew, which consists of two or three excavators and five to nine haul trucks, has been working fairly steadily since excavation work began in April.
"For the most part, that's all they've been doing, hauling marsh," said Henkel. "They're excavating the marsh, and backfilling it."
Trucks haul a load of marsh off site, then return with a load of sand. The process is repeated until sand has replaced marsh.
When excavating a marsh as part of the bypass construction, crews backfill sand to 2 feet above the original ground level. Dirt is then placed on top of the sand to get it within 2-1/2 feet of grade, with select borrow placed on top of the dirt.
James is using Caterpillar 375 excavators and Caterpillar 740 haul trucks on the marsh truck crew.
"Depending on the length of the hauls, we've had anywhere from five to nine trucks on that crew," said Henkel.
A couple of utility excavators are also part of the marsh truck crew.
Almost all of the marsh excavated as part of the construction of the bypass has been disposed of at two off-site waste sources.
"When it dries out a little bit, we spread it out, seed it, and within a year or so most of it will become farm fields," said Henkel. "We've also built three pretty big berms for people to shield them from the bypass."
By mid-September, James was a little more than half-done with the approximately 3.2 million yards of excavation work on the first contract for construction of the Burlington Bypass, said Henkel.
James Peterson Sons, Inc., Medford, Wis., has been hired as a subcontractor for the excavation work and is also doing the gravel work for Highway 142.
"They built the north end in April, early May. Then they built the south end, and were gone for quite a while. They're back now, and have been here maybe half of the summer," said Henkel.
Besides the marsh truck crew, H. James & Sons has one other truck crew and a scraper crew doing excavation work on the job.
The second truck crew has been grading tie-ins on the ends of side roads and grading intersections, as well as grading some of the muddier sections of the job.
"That's been a smaller crew that's been doing a lot of cleanup stuff, and some of the tighter grading," Henkel said.
The smaller truck crew has been using a Caterpillar 345 excavator, Volvo haul trucks and a couple of utility dozers.
The scraper crew, typically working with five or six Caterpillar 641B scrapers, two Caterpillar 9L dozers for pushing, a rubber-tired dozer, and several graders, has been doing the bulk of the borrow excavation and the common excavation.
In total, approximately 1.8 million yards of borrow is expected.
"We've wasted quite a bit of dirt because a lot of the material we've been grading has been poor. The common excavation has not been very good. It's been water-bearing silt," Henkel said.
Approximately 1 million yards of granular backfill is going into the marshes.
About 460,000 yards of common borrow is expected.
"That's probably going to run over because of the poor common that's had to be wasted," Henkel said.
In addition, there is another 325,000 yards of select borrow, which is being used for the top 2-1/2 feet for pavement structure.
"There's been a lot of EBS on the job. If you drive the project and look at it, a lot of the ditches are in water. The north half of the project, pretty much every ditch is in water. The subgrade isn't much above that, so the subgrade soils have been very poor," said Henkel.
He estimated three-quarters of the dirt is good.
"When you have a million yards of common excavation and a quarter of it's bad, that's a lot of poor soils," said Henkel.
With 13 straight days of rain in June and 12 inches of rain in a three-week period in late August and early September, it was a wet summer in Burlington.
"The borrow is good. The granular sources are good, so we've been able to get rid of the poor soils and bring better on-site. That's really helped us keep moving," said Henkel.
In addition, crews worked 12-hour days during the summer and have worked as many days as possible despite the conditions.
"When Peterson is here, there are four grading crews running," Henkel said. "That's a lot of equipment."
After shutting down for the winter, H. James & Sons will be back on the job next spring.
"We'll probably have three-quarters of the material graded this year, and have about a quarter of it next year," Henkel said.
Approximately 300,000 yards of common excavation will be done in 2007.
The first phase of construction of the Burlington Bypass is expected to be complete in July of 2007.