Grading Technology Solves Ballpark Challenge
During the fall of 2007, a last minute decision was made by Onondaga County Parks officials in Syracuse, N.Y., to replace the decade-old Astro Turf that covered the playing field at Alliance Bank Stadium with natural turf. Alliance Bank Stadium is home to the Syracuse Chiefs, an AAA affiliate of the Toronto Blue Jays. Onondaga County hired Appel Osborne of Syracuse, N.Y., to design the project.
That decision to go natural proved to be the trip wire that set off an explosion of challenges for the ground crew. The drainage system had to be retrofitted, numerous slope changes in the field itself made the use of laser control equipment very difficult and the stadium grandstands blocked out GPS on the equipment.
All the problems landed in the lap of Paul Young, project superintendent for Clark Companies, an engineering and construction firm that won the bid to do the work. Clark Companies, an organization that has been in business for 60 years and has specialized in building sports fields for 30 years, also was involved in field construction at Giants Stadium at the Meadowlands Sports and Entertainment Complex in East Rutherford, N.J.; the National Soccer Hall of Fame, Oneonta, N.Y.; and Doubleday Field in Cooperstown, N.Y. Young quickly found out that Alliance Bank Stadium was unlike any other sports project he had encountered.
He knew from experience that baseball fields can be more complex to construct or renovate, especially when it comes to grading. Football and soccer fields are flat longitudinally, for instance, and typically have half a percent crown from the center to the side lines.
Baseball fields, by comparison, are a little trickier, although they are basically only two grades, Young explained. "They are level on the infield and then the pitch rises half a percent from the bases up to the pitcher's mound. After that the grade usually falls at a constant rate of percentage to the outfield." Because an outfield is not symmetrical—center field could be 400 feet out, while left field and right field might be 330 feet — there could be as much as 70 feet to 90 feet of difference between the points "The field has to be level all the way around, so there is a whole different grade involved in that," Young remarked.
In most cases a cone laser or system of dual lasers can be set up to work for that type of application.
But when Young hauled in his laser control machine for the Alliance project, he found out his equipment couldn't do the work. Although the plans called for him to laser grade the field, the outfield did not lend itself to laser grading. He couldn't use a cone laser, he couldn't use a regular dual grade laser, and when he tried a specific GPS system the satellite coverage wasn't adequate because of the structure of the stadium obscured the skyline.
Without proper equipment and technology, Young had no intention of "muddling through the job," he said. He contacted Admar Supply Company in Syracuse, a company he had worked with many times on different projects. Admar's machine control specialist, Tom Krenzer, based in Rochester, was the installer of the laser control system on the machine Young already owned.
After finding out that dual lasers and GPS alone wouldn't work, properly Krenzer sent out a Case 650 dozer equipped with a Topcon Millimeter GPS, Topcon's HiPer Lite+ dual constellation receiver plus 3-D machine control software and controller.
Krenzer explained: "On a regular field you wouldn't use GPS. You would use a regular laser. But by installing the millimeter system, we were down to precise measurements of up to 1/300th of a foot, which is extremely accurate."
That degree of precision is possible because the Topcon system has a fan laser called LazerZone that shoots a beam that sweeps a 2,000-foot diameter area with a 35-foot high wall of light.
After creating a 3-D model of the field, a HiPer Lite system was added. HiPer Lite is a handheld rover unit with a reader. Both model and the handheld device were set up along with the Case dozer equipped with the 3DMC.
Although this enabled the equipment to achieve 5 to 7 hundredths vertical control, which was fine for the base material, Young needed tighter control for sub base and future layers that had to be installed. The millimeter system was set up allowing 15 feet of elevation change each way from the center. After calibration, the Topcon technology that utilizes signals from both the GPS and GLONASS satellite systems obtained 1 to 3 hundredths vertical error with the survey rover and the dozer. That worked especially well on the home base side of the field, where single constellation satellite coverage was limited due to skyline obstruction.
"GPS control — using signals from a single system of satellites — is not always used on athletic fields," said Krenzer. "Topcon has the millimeter enhancement and the use of GPS and GLONASS satellite signals, which allow plus or minus 2 millimeters of control. Using this advanced technology, we were able demonstrate to Clark Companies that 3D GNSS can be used in the installation of playing surfaces that demanded special attention and equipment."
In pulling up the Astro Turf, Young discovered it was, in his words, "old style. It was a shock pad with holes in it, and under that was porous pavement that drains vertically. Then, there was a drainage system under that."
Young wanted to use the existing drainage system, so he cut the stone base out and put in a 2-inch drainage layer of pea stone. Eight inches of sand covered the stone so the natural turf could grow. All this changed the grade, he said, so the warning track was level all the way around.
"That is what complicated the grading plane," Young said. "There were grade changes made when they moved from the Astro Turf to the sand base turf. It had to have a little more pitch on the sand base than on the old asphalt."
One unexpected benefit that came out of the job had to do with keeping the existing drainage system and using the HiPer Lite+ handheld unit. The handheld device uses a Windows-based program, so Young was able to install a map of the stadium on it.
"It had a little C card with it, so I was able to quickly install a map of the stadium on it, plot all my irrigation boxes, which are buried in the warning track in such a way that you don't really know where they are. I was able to identify drainage clean outs and also locate all the sprinkler heads. The Hiper Lite told me the elevation and that allowed me to put a tag where a clean out, quick coupler or an out box was located. When it came time to give all that information to my CAD (computer aided design) guy in the office, I simply downloaded the information from the C card and he put an overlay on the drawing so the add-fill was done as we went along."
Added Admar's Krenzer: "If they ever have trouble with the irrigation system, for instance a leak or broken connection, they can take a HiPer Lite, go back out in the field, put the flash card in the data collector, bring up the files and literally walk to a point within an inch of where the connection is."
The entire project came in ahead of schedule. "We started the project in the first week of September 2007, and that included removing the old Astro Turf, removing the blacktop, and removing the sub grade — and actually laid sod the first week in November," Young said. "[The technology] saved me at least a week and a half and maybe even two weeks," Young said. "It also saved me a lot of manpower. That translates into real savings on the entire job."