The tight tolerance requirements specified by the Federal Aviation Administration caused difficulties for an almost completed project at the Cedar Rapids, Iowa, airport.
However, DeLong Construction Inc., headquartered in Washington, Iowa, accomplished the task with the aid of GPS equipped equipment.
It is not that long since this type of equipment was introduced to the construction industry, Paul Ruckman, GPS technician and land surveyor of DeLong Construction, recalled.
Ruckman has been employed by the company since April 2002.
“I was hired to be a grade checker and I’m still at it. DeLong Construction has come a long way since my first day,” he said. “I remember pulling tapes and shooting grade through a hand level, now it’s mostly done by GPS. I do all of the file building for all the jobs, I program the equipment, I set grade stakes for the operators, I also do the training for the operators. [Those are] my responsibilities here.”
As of mid-November DeLong Construction, Inc. is completing three airport projects for the 2008 season. One is in Independence, Iowa, where they are carrying out a total reconstruction of the runway and taxiway. Another is in Iowa City, Iowa, where a partial runway reconstruction is under way.
The third is the Cedar Rapids job, which involves the total reconstruction of the taxiway of the Eastern Iowa Airport.
“All of the airports that we have come across have got ridiculous tolerances for accuracy of work performed,” Ruckman observed. “Without GPS I think it’s almost impossible to meet these tolerances in a timely manner. All of the jobs that DeLong are awarded are now done with Topcon GPS guidance of some sort. That is where I play a vital role in the process of getting the job rolling.”
“This is DeLong’s second year in the Eastern Iowa Airport, as we were awarded a contract to reconstruct another portion of the taxiway in 2007. It is an ongoing operation at the airport, which is to be done in phases, and the next is scheduled to take place in 2010,” Ruckman said.
“DeLong Construction took to the dirt work on May 5, 2008. We used a wide variety of equipment on the job,” he continued. “We used a Volvo 460 excavator to load the side dump trucks that hauled the crushed concrete and Caterpillar Challenger 865Bs pulling Icon scrapers to do most of the dirt placement. We also used a John Deere 750J IGC bulldozer outfitted with Topcon’s 3-D machine control and a Caterpillar 140H motor grader strapped with Topcon’s 3-D machine control.”
DeLong’s fleet of equipment for the job is rounded out by a John Deere 700H bulldozer and a John Deere tractor pulling a sheepsfoot roller, and a 563E smooth roller, a 277C skid steer and a 938G loader, all from Caterpillar, plus a Hartl 1270 crusher and a Trident screen plant.
DeLong owns two motorgraders with GPS, five bulldozers with GPS, and three range poles. The company does all of its GPS programming in-house and has had only one file where help was needed from an outside source.
“First you receive a drawing from the engineer and you begin building the 3-D model if one wasn’t already provided for you. Then you load all the information into your data collector and you are ready to go to the field, where you go and localize the job with your range pole,” Ruckman explained. “Localize means placing the drawing into field by calibrating on control points set by the engineering firm. Now you are ready to program the machines with all of this information. Once you have done this you are ready to go to work.”
The range pole supports the Hyper Lite rover on top and carries the FC100 Data Collector on its side in a cradle. Its job is to basically serve as a measuring device for survey applications.
“The range poles play a vital part in the process of every job. You use them to check in on the control points periodically to assure that your system is checking in vertically. Also they are used to check the machines to make sure they are not off vertically due to blade trim wear,” Ruckman went on. “There really is no limit as to what the range pole can do for a company. You can set grade stakes, do site topo’s, record any info needed, the list goes on and on.”
Ruckman praised Cedar Rapids dealer Star Equipment Ltd. for doing a very good job of keeping up with DeLong’s demands in a fast-paced industry.
“We constantly try and work together to keep up on the latest in the Topcon market and also communicate ideas of where we think the system could be improved to help with the work we do in the region we are in. Dan Wiese at Star then passes this along for us to Topcon,” Ruckman said.
“We supplied the Topcon 3D GPS and automatic control system for the Caterpillar 140H motorgrader used on the job,” said Dan Wiese, GPS and machine control specialist at Star Equipment, adding they had assisted DeLong with all of its GNSS (Global Navigation Satellite Systems) equipment.
Wiese went on to further describe the use of GPS in projects such as these.
“At the beginning of the job they will set up a Hiper Lite base station and localize the project using a Hiper Lite rover on a range pole with Topcon FC100 handheld and Pocket 3D Grade Management System. They will then check the job site topography using the Hiper Lite and Pocket 3D to assure that the 3D data file is accurate. At this point, the data files are loaded into the Topcon Graphic 3D-MC control box on the dozer and motorgrader for stakeless grading. The Hiper Lite rover and Pocket 3D range pole then becomes a tool for grade checking and staking to guide the non-GPS equipment. At the end of the project the rover is used to add any ’as built’ information to the data file and to quality check the job,” he concluded.
“There are many phases to building a runway or taxiway and Cedar Rapids was no exception,” DeLong’s Ruckman noted. “First we ripped out the old taxiway and began recycling the concrete to later be used for rock under slab. Around 68,000 square yards was crushed. Other crews worked to get the old underground electrical ripped out. We started out by stripping off the topsoil for re-use for re-spread. Then we began working on the new taxiway grade, and then on the drainage ditches for the site.”
Problems were encountered completing the dirt work in a timely manner because of the summer 2008 floods in Iowa, historic and widespread inundations following continual and heavy rain state-wide.
Cedar Rapids was particularly hard hit, with more than l,000 blocks affected. As a result, almost 4,000 homes were flooded, as were the U.S. and county courthouses, the local jail, two museums, the public library, and numerous businesses. A number of the latter were forced out of business as a result. In addition, the city’s railroad bridge was destroyed by floodwater, while for a time the only bridge open for vehicular traffic was that carrying Interstate 380 across the Cedar River, and even then restrictions applied. With many roads closed DeLong employees had to travel two hours more than their normal commute time just to get to work.
Not surprisingly therefore the company had difficulties meeting the initial completion date of mid-October. The anticipated completion date is now Thanksgiving.
“Due to the weather we also had trouble meeting compaction [requirements], so we resorted to placing fly-ash on the grade. We placed 1,100 tons of fly-ash down. The grade was so wet that the bulldozer had to literally pull the fly-ash tractor through the grade along with the tilling machine,” Ruckman recalled. “Once we overcame that obstacle, that cured our problem and we graded the dirt under slab to a tolerance of only plus or minus 0.04 or four hundredths of a foot. The dirt grade was checked by a surveyor from Foth/Engineering Alliance Inc., the engineering firm in charge. He checked the grade in a grid of 25 ft. throughout the entire grade. Then we had to step aside and let the underground electrical and drainage pipe be installed, then came the rock.”
The rock was placed by DeLong and left one-tenth above grade, after which the concrete crew went to work on the taxiway. They were to trim the rock one-tenth and had a tighter tolerance of plus 0.0 or minus 0.03 below grade, to be checked in the same manner by the engineering firm as DeLong’s work had been.
DeLong was asked to assist with the trimming by taking care of all the connector taxiways. “Supposedly the trimmer could not cut in a radius to those tolerances, so we helped out,” Ruckman said. “We put our Caterpillar motorgrader equipped with Topcon’s 3-D machine control system to the job. It was able to trim the rock to the specified tolerance with no problems.”
After completing the connector ways DeLong was asked to touch up areas in the main line where the trimmer was unable to perform to the specified tolerances, so the company graded behind the trimmer to correct the problem areas.
“There are a lot of variables involved to get tolerances like this out of the GPS system. Most people say that it’s only good to one-tenth of a foot. I say it’s as good as the people operating it, from the design side to the machine side,” Ruckman stated.
At this time DeLong Construction is once again waiting for the wet weather to pass so it can finish up with the rest of the work in its contract, which involves backfilling the new slab that has been poured.
Founded by Dana DeLong-Patterson and Deran DeLong in 1994 as an earthmoving contractor, DeLong Construction Inc. now specializes in underground utilities installation, heavy highway earthmoving, demolition, site development and rock spreading. It serves customers throughout Iowa, particularly in the east central and southeastern areas of the state.
Its associate company, DeLong Recycling Inc., was founded in 2007 and offers concrete crushing. It also handles brick, foundation rubble, and asphalt pavement recycling. Past projects of a similar nature to the Cedar Rapids job include 200,000 cu. yd. (152,910 cu m) of earth moving at Independence Airport in Independence, Iowa as well as 300,000 cu. yd. (229,370 cu m) of earth moving and installation of 23,000 linear ft. (7,010 m) of storm piping at Fairfield Airport in Fairfield, Iowa.
Star Equipment Ltd. was founded in 1968 by Max and Beverly Bowman, both of whom are still involved with the family-owned business. Now run by Bruce, Brad, and Brett Bowman, it has more than 70 employees at locations in Des Moines, Ames, Cedar Rapids, and Waterloo, Iowa. The company operates state-wide as well as in parts of Missouri, Illinois, Minnesota, South Dakota, and Nebraska, offering clients general and light construction equipment and specialty products. In addition, Star Equipment’s repair department is equipped with mobile lube and service trucks and operates a 24 hour emergency service.