It’s seldom that you’ll encounter an endangered bird species confronting you in the middle of a paved public highway. But, that is exactly what happened at the construction site of a new public elementary school in Pasco County, FL. Several pair of Sandhill Cranes decided to avail themselves of one of the retention ponds that had been excavated at the site. Periodically they wander out on the road, almost as if to challenge passing motorists. The cranes, as it turned out did not hinder site development. Rather, the birds served as a pleasant distraction. The David Nelson Construction Co. held the $753,000 contract for the site development for the Pasco County school. Nelson’s crew used its new Link-Belt 330LX hydraulic excavator to help clear the 20-acre site and to dig the trenches for the underground utility lines. The Pineview Elementary School F, on Pine Parkway in the Lake Padget area, was the third similar structure built in the area by the Beck Group of Dallas, TX, as project manager. Kevin Reardon, Beck’s on-site superintendent, said it was imperative that Nelson finish its work on schedule to assure the overall project’s on-time completion. The school’s planned opening is set for August 2003. Teachers normally want to move in about six weeks prior to the opening date to start preparing for the next school year. Nelson Construction used the 78,000-lb. excavator to install the 8-in. PVC sanitary sewers, followed by the 18- to 30-in. RCP storm drainage, 4-in. PVC water mains and separate 8-in. PVC fire protection lines. The company only had a short, four-week window to bring all the pipe paraphernalia onto the job and to install and backfill the lines. “My boys really smoked them on the pipework,” said Dave Kelly, pipe foreman. “In one day, working on the sanitary sewer line in a 9-foot deep cut, we started work at 9:30 in the morning and finished putting the manhole in at 2:15 the same afternoon,” said Kelly. The day’s work also included 167 ft. of 8-in. pipe, 120 ft. of 4-in. pipe, and the manhole, as well as digging the trench, setting the laser grade, laying the pipe, backfilling and compacting the trench. “That’s really smoking,” noted Kelly. Crews laid a total of 1,500 ft. of sanitary line, 2,500 in. of storm drain, 1,200 ft. of water and a similar amount of fire line. Workers also put in 14 manholes to put in which ranged 4 to 13 ft. deep. Nelson used Class C-900 PVC pipe that came in 20 ft. lengths weighing 150- to 200-lbs. each, explained Kelly. “The 8-inch diameter C-900 class PVC gravity flow sanitary system depths ranged from 11-feet deep at the beginning to 9-feet deep at the end. A laser alignment system was employed by the pipe crew to ascertain the precise proper grade elevations,” continued Kelly. The Class E sandy soil weighed approximately 3,000 lbs. per cubic yard wet, and was easily handled by the Link-Belt’s 54-in., 2.4-cu.-yd. bucket from C&P Inc., said Kelly. The group opted to do without a trench box. Instead, the material was being side cast as the trench was excavated wide and benched back to the safe angle of repose in accordance with OSHA specifications. Kelly explained that this method was faster than using a steel trench box. Safety here was of paramount importance. Pipe trench backfilling and compaction was accomplished using the hydraulic excavator and a small tracked dozer. Then a small compactor was used at various lifts over the pipe. Kelly said that the 330LX is not the first Link-Belt the company has owned, but he felt it is one of the most technically advanced. “The excavator is designed to help make even the most experienced operator more proficient,” he explained. The Link-Belt LX series excavator has an integrated electronic engine control and InteLX computer system. Due to the good weather and the Link-Belt, the job was done ahead of schedule. “Nelson did an outstanding job by keeping pipe installation on time — the overall project was completed about three weeks ahead of schedule. The importance and need for on-time completion can best be illustrated by the fact that every school that I have built like this, was over-booked by at least 10 percent by the time it opened. Pasco County, just north of Tampa, is rapidly growing and it is difficult to keep up with its need for new schools,” said Reardon. Finishing the sitework and installing the utility lines on time is paramount to the work that must follow, Reardon explained. “To erect the prefabricated, one-story, metal building and roof and to construct the masonry exterior requires a crane to work over the pipe trench location. It normally requires nine-and-a-half to 10 months, from start to finish, to build a school of this type. We might lose a day or two to cold weather, but the rainy season is past and with Nelson having completed the site work, we should have no problem bringing this school in on time,” Reardon said. Nelson had a short dewatering area that required wellpoints between the first two manholes on the sanitary sewer line. Otherwise, the groundwater table was low enough to be of no concern during pipe installation. They also had a water line road jacking —boring under the highway — that required steel pipe insertion. “It was a little more complicated than that. We had to set a 700-pound ’doghouse’ manhole over an existing line out front,” said Kelly. “Before we could do that, we had to cut and move a live 8-inch raw sewer, force main. We dug over 12 feet deep with the 330LX backhoe. Then we used it to lift, lower, and position an 18-foot long pipe joint with two 7-foot long legs with fittings coming off it. That Link-Belt’s a good machine, it’s a real workhorse,” Kelly added. David Nelson founded the company, which is headquartered in Palm Harbor, FL, in 1976. Mike Barker, vice president of operations, said the company is a true general contractor. The company builds highways, roads, streets, and sewer treatment plants. It also designs and constructs commercial buildings and does site development and installs underground utility lines of all types including storm drainage, sanitary sewers and water mains. Barker is a licensed pilot who flies his own Robinson 22 helicopter. It enables him to visit three to four of the company’s jobs a day and provides the “hands on” vice president with a better perspective of the projects.This story also appears on Construction Equipment Guide.
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