Edited by Loren Faulkner
After years in the excavation business, this spring Jeff Swanson found his way to the football field.
That's because there's a new generation of field surface that makes the original AstroTurf a relic of the past. High schools across the country are looking to the cheaper maintenance of a state-of-the-art field surface that looks and feels like grass, and withstands a decade of constant use without wearing through.
So excavating companies are grading football fields these days, and earth movers like Swanson — who co-owns ESS Engineering of Stockton, Calif. — are completing jobs twice as fast as they would have before the advent of machine-control equipment driven by satellite-positioning technology.
The first generation of AstroTurf was known for the bruises and contusions that football players suffered upon colliding with the ground, where only a cement slab underlay the turf surface. But now, several turf companies are bringing a new life to artificial playing surfaces. Schools across the country are switching to a new generation of turf that purports to look and feel like real grass.
The current design involves stretching the playing surface over crushed-up recycled material — like tires, or even recycled sneakers, in the case of one firm. And schools that once scraped together maintenance funds for grass fields are now finding creative ways to raise the $600,000 to $900,000 it takes to rip up a playing surface, grade and base-rock it, and hire a specialized contractor to apply the turf system.
At Yuba City High School just north of Sacramento, ESS graded the entire playing area of Honker Field, where a soccer field overlaps the smaller football field, all of it ringed by a running track.
ESS does mostly grading and paving, usually limited to site prep, parking lots and roads. Due to the varying slopes needed in a small area for a football field to drain properly, ESS' road experience was not lost on the project. A football field, like a road, features a crown down the center with a 1-percent cross slope descending to either side.
But there's also the surrounding track, which requires its own specific grading scheme, including a graduated slope to contour the turns at either end. That precise varying grade then fades into the track's two flat straightaways.
Slopes gradiating into a perfectly flat surface are problems for traditional grading methods, but are just part of the job when GPS technology is introduced. ESS, like other companies, used lasers before the advent of GPS technology in earth work. But lasers aren't much help when a surface requires varying contours. And although the deft touch of a skilled blade man can always be counted on to nail down such a grade, the job goes much faster with GPS.
"Your efficiency is a lot more than it is with lasers," Swanson says. "When you get into different angles and grades, you need GPS. There are guys that can do it, who at least can come close (without GPS), but there's always a certain amount of human error."
After years of running scrapers and motor graders, Swanson started ESS Engineering with his brother in 1997. ESS did the excavating on three field-resurfacing projects in the Sacramento area this spring — the first time the company had ever graded a football field. Users of GPS-enabled machine control systems report productivity gains of anywhere from 25 percent to 100 percent; ESS was finishing its field grading and base-rocking in three weeks — about half what it would have taken without GPS, Swanson says.
It's an increasingly accepted truism in earthwork — especially for small companies — that without cutting-edge technology, you can't compete. When ESS switched from laser to GPS technology two years ago, it went straight for a Topcon system that uses a Russian GLONASS satellite system in addition to the U.S.'s Global Positioning System (GPS). Drawing on signals from more satellites, accuracy is increased, Swanson said. He likes to receive positioning data from at least eight satellites for fine grading.
At Honker Field, Swanson normally had good signals from nine satellites — seven GPS, two GLONASS — showing on his Topcon FC-100 handheld field controller, which runs on the Windows CE operating system. With the extra 20 satellites of the GLONASS system comes the capability for millimeter or better accuracy and little to no downtime. Satellites beam positioning signals 24/7. Swanson also runs Topcon's 3D-Office software on a laptop, allowing him to create jobsite design files and export efficiently to the field controller.
The GPS system adjusts the blade as the motor grader moves. "The surfaces are multifaceted," Swanson says. "You've got lots of angles. And with the GPS system, the grader doesn't have to deal with cross slopes."
John Boyette, an experienced motor grader, said the Topcon system was intuitive enough that he could begin using it right away. "The learning curve was very short, almost non-existent."
While the machine control system doesn't do the work for you, Boyette says the precision control of the system, constantly adjusting the blade as the grader moves down the football field, subtracts a few passes from each grading run — exactly the kind of savings a contractor needs while fuel prices soar to record highs. And because a GPS system replaces the need for traditional surveying methods, machinery doesn't sit idle while waiting for surveying and staking.
For ESS Engineering, it all leads to the efficiency that allows a smaller excavating company to compete in the bidding process. And that means more football field resurfacing, when school lets out for the summer once again. "That's what it's all about," Swanson says.
Editor's Note: Wes Sander is a freelance California-based technical writer.