Court Construction & Maintenance Guide: The Hard Facts
With its resistance to cracking, post-tensioned concrete is becoming the go-to choice for tennis courts.
The tennis industry has changed and evolved, and nowhere is this more evident than on the court itself. New lines and new technologies have certainly grabbed their share of headlines, but the real news may be what’s going on below the surface.
Times were, when it came to hard surfaces, asphalt courts were the standard and could be found in parks, homes, clubs, even in championship arenas. However, as times have changed and oil prices have fluctuated, post-tensioned concrete has been quietly making its move to become the go-to choice. There are many reasons PT concrete courts have been successful, but ask any specialty court contractor and you’ll consistently hear one answer: Properly installed, they won’t crack.
To back up, post-tensioned concrete courts are those that are reinforced by sheathed steel cables within the concrete slab. After the concrete has begun to set and has reached sufficient strength, the cables are tightened and held permanently under stress. The cables exert a tremendous compressive force, holding the pavement at the same tension and guarding against cracking.
Consider the alternative: Asphalt, as a bituminous pavement, is poured and smoothed into a tennis court surface before it is coated. Beneath the coating, the asphalt dries and shrinks as it ages (this is not a flaw in the mix; it is the nature of asphalt). The brittle pavement becomes less resistant to damage and more prone to cracking and crumbling, and areas where freeze-thaw cycles are the norm will see even more of this. As a result, a court that once looked smooth and unblemished might look surprisingly cracked and aged within a comparatively short time.
A ‘Standard’ Technique
Post-tensioned concrete, meanwhile, does not respond to freeze-thaw cycles and will not get brittle in a few years. Even in warmer areas, tennis court contractors are leaning toward this method of construction over other concrete uses.
“Post-tensioned concrete has been a standard tennis-court construction technique in the USTA Southern California section for many years,” says Richard Zaino of Zaino Tennis Courts in Orange, Calif. “We discovered in our earliest experience with engineered post-tension courts that were designed and built due to poor soils conditions, the post-tensioned concrete courts were performing much better than steel rebar-reinforced slabs on good soil conditions. So we took what was given to us by the post-tensioned concrete engineers for specific sites and made this a standard in all our court building.”
Those who have been thinking of replacing their current courts — or adding new ones — likely have plenty of questions. Before you make a decision, though, it’s best to consult with a court contractor. Here is some information to bring with you to the table:
- How many courts you’re talking about.
- Any budget you have in mind.
- The window of time you are seeking to have work done.
- Whether the courts are (or will be) lighted for night play (if lighting already exists, make a note as to where the posts are set).
- Whether the courts are currently fenced.
Other factors will influence the design and cost of the project, and the court contractor can help you decide what is important. In addition, court owners and facility managers should be prepared to do their homework in order to make the best decision and get the most out of the project.
Checklist for PT Concrete
David LaSota of D.W. LaSota Engineering of Patton, Pa., offers some advice regarding some items for an owner’s checklist (or perhaps one that should be given to a consultant on the project):
- Hire a professional engineer who is familiar with post-tensioned slab design and construction. Some clients (and professionals) leave it up to the contractor to design the PT slab; however, not all contractors have the engineering expertise to perform such services. Check references and ensure your chosen professional is the right person for the job.
- Most tennis courts include net posts, nets, center strap anchors, center straps and fencing as part of the job. The professional should ascertain these elements are incorporated safely into the post-tensioned project.
- Installation of a vapor barrier under the slab can minimize the transmission of water vapor through the concrete slab that can cause delamination of the acrylic surfacing. The vapor barrier also reduces the under-slab coefficient of friction, which minimizes the number of cables required to achieve the required compressive forces. The owner and/or consultant should make sure this element is not left out of the design/construction process.
A few other items for the owner’s or consultant’s checklist include:
- Use stone screenings in lieu of sand for the cushion layer under the vapor barrier and concrete slab. The stone screenings will bind together and not displace as easily as sand.
- Construct a thickened edge around the perimeter of the slab to provide for increased concrete coverage around the end anchors.
- Provide the proper level of pre-stressing to overcome the slab-to-subgrade friction, which will minimize restraint-to-shortening cracking.
- Insist on proper recording of cable elongations to ensure the proper stressing of cables.
- Ensure the slab is adequately moisture-cured to minimize the amount of shrinkage cracking that may occur.
- Ensure the field personnel have adequate training in the cable stressing operations because this process involves extremely high forces and can be dangerous if not done properly.
- Do not let unauthorized personnel (visitors, vendors or others) into the area while cables are being stressed.
If it sounds like a lot, well, it’s because post-tensioned concrete construction is a specialized art form. It is not the same as pouring a driveway or a sidewalk, and should not be mistaken as such. It will require specific equipment and expertise.
The reward, however, can be a long-lasting surface that provides enjoyable play with minimal upkeep — for years to come.
See all articles by Mary Helen Sprecher
About the Author
Mary Helen Sprecher is the managing editor of Sports Destinations Management Magazine, a niche business-to-business publication for planners of sports travel events, in addition to being an RSI Contributing Editor. She is the technical writer for the American Sports Builders Association and works as a newspaper reporter in Baltimore City.
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