A.S.B.A. Guidelines for Tennis Court Construction

Section II.H. – Post Tensioned Concrete Slab Tennis Courts

1.0 Purpose

The preferred method of concrete court construction is the post-tensioned concrete slab. This system allows for a much larger single monolithic pour, eliminates the need for expansion joints and minimizes reflective and surface cracking.

2.0 Slope and Elevation Requirements

All excavating, filling and grading requirements and compacting work of the subbase should be performed so that the finished subgrade is 4″-6″ above the surrounding ground and slopes not less than 0.83% (1:120) and not more than 0.1% (1:100). Each court must slope in a true plane, preferably from side to side (but from end to end or from corner to corner also are acceptable), or in the shortest direction for good drainage and water runoff. The court should never be sloped from the net line to the baseline, from the baseline to the netline, from the sides to the centerline or from the centerline to the sides.

3.0 Base Preparation

Refer to Section I.C., Site Preparation, Earthwork, Drainage and Subbase Construction.

4.0 Concrete Construction
A. Apron
The overall dimension of an individual court should be 61′ x 121′ to provide a 6” apron around the court or 62’ x 122’ to provide a 1’ apron around the court. This additional footage helps prevent vegetation intrusion, facilitates landscape maintenance and adds to the overall cosmetics. Fencing should remain at 60′ x 120′. Fence posts, net posts, sleeves and center anchor should be installed prior to or during concrete placement. Fencing should be completed prior to surfacing.
B. Moisture/Vapor Barrier
As with all concrete construction, a moisture/vapor barrier, consisting of polyethylene (10 mil. minimum thickness) should be installed prior to installation of any steel and/or cables. Overlap polyethylene sheets at least 6″ and tape joints. Once in place no vehicular traffic should be allowed on the moisture/vapor barrier nor any other object which could puncture the barrier or otherwise compromise the integrity of the surface. All concrete should be pumped, not driven onto the court. Excessive loads at any time are unacceptable.
C. Cement
Cement (Type 1 or 1A) should conform to one of the Standard Specifications for Portland Cement, ASTM C 150 or Specifications for Blending Hydraulic Cements, ASTM C 595, excluding slag cements Types S and SA. Do not use curing compounds.
D. Air Entrainment
Air entrainment by total volume of concrete should be:

4 to 6% for 1 1/2″ maximum size coarse aggregate, 5 to 7% for 3/4″ or 1″ maximum size coarse aggregate, 6 1/2 to 8 1/2% for 3/8″ or 1/2″ maximum size coarse aggregate.

E. Aggregate
Aggregate should conform to Standard Specifications for Concrete Aggregates ASTM C 33. For concrete work that is 5″ thick, the nominal size of the coarse aggregate should not exceed 1 1/2″ and for concrete work that is 4″ thick, the nominal size of the coarse aggregate should not be greater than 1″. Fly ash or other additives are not acceptable.
F. Thickness of Concrete
Concrete work should be 5″ thick if the location of the tennis court is such that it will be subject to more than three freeze/thaw cycles annually. If the location is such that not more than three freeze/thaw cycles occur annually, concrete may be 4″ thick.
G. Post-Tensioning
Post-tensioning material should consist of seven wire stress–relieved strands, conforming to ASTM A 416, with an ultimate strength of 270 KSI. Strands should be coated with a permanent rust preventative lubricant and wrapped with plastic sheathing. If strand sheathing is damaged or removed, it is to be repaired by taping. A maximum of 6″ exposed strand is permitted at the anchor. End anchorage devices will conform to Post-Tensioning Institute (PTI) specifications. All dead end anchorages must be power seated. All strands are to be supported on chairs and tied at all intersections or securely supported in beams to prevent vertical and horizontal movement during concrete placement. Cables should be laid out in grids no greater than 4′ on center. Concrete must be well consolidated, especially in the vicinity of strand anchorages. Strands should be anchored at 28.9 KIPS, but may be initially stressed at 33 KIPS. A 9” diameter centered on the strand axis by a 36″ length should be allowed for stressing equipment clearance. The stressing process generates tremendous pressures and extreme care should be taken to prevent injury from operator error or failure of equipment or materials.

Slabs should be designed using acceptable engineering practices in accordance with the American Concrete Institute Building Code Requirements for reinforced concrete and the Post-Tensioning Institute’s tentative specifications for post-tensioning materials. The soil condition and plasticity index of the court site should be considered in determining strand spacings and beam requirements.

H. Forms
Forms should be set accurately to the lines and grades indicated on drawings and secured to prevent settlement or movement during placing of concrete. Forms should remain in place until concrete has taken its final set.
I. Joints
1. Single courts should be poured as a monolithic slab.
2. Double courts may have an elastomeric metal construction joint between courts. This joint may also be placed on the net line if needed. Joints should never be installed in the play areas.
3. Multiple court banks may have an expansion joint between every two courts. Where this occurs, the cables will be “dead ended” on both sides.
4. For multi-court banks, an accepted alternative expansion joint method would be to construct a common expansion joint between every two courts with a T-joint method. The cabling system can be continued through the system to allow for tension to be applied at the end of the total slab distance.
J. Concrete Proportioning and Mixing
The concrete should have a compressive strength of not less than 3,000 psi at 28th day after casting. Ready-mixed concrete should be mixed and delivered in accordance with ASTM C 94, Specification for Ready-Mixed Concrete with a 4″ maximum slump.
K. Placing and Finishing
Concrete should be placed by pumping method. At least a full court should be placed in one continuous operation without intervening joints of any kind. Concrete should be spread, consolidated, screeded, bull-floated and finished in accordance with Section 7.2 of ACI (American Concrete Institute) Standard 302, Recommended Practice for Concrete Floor and Slab Construction. When concrete is sufficiently set to withstand foot pressure with only about 1/4″ indentation and the water sheen has left the surface, the slab should be uniformly finished by power floating and troweling. The final finish texture should be a medium broom finish unless otherwise specified by the surface manufacturer. No curing compounds should be used at any time.
L. Surface Tolerances
The finished surface of the court should not vary more than 1/8″ in 10′ when measured in any direction.
M. Curing
Immediately after finishing, the concrete should be kept continuously moist for 7 days by covering with polyethylene film or waterproof curing paper, or by sprinkling or ponding or other acceptable coverings. No curing compounds should be used at any time. Curing time should be in accordance with surfacing system manufacturer’s recommendations. Timing is critical on all of the above due to the possibility of disturbing the finished surface.

Drawings:
Typical Sections Post-Tensioned Concrete Court Pavement

Note: Refer to Guidelines for:
1.A. General Conditions for Construction
1.B. Site Investigation
1.C. Site Preparation, Earthwork, Drainage and Subbase Construction
1.D. Vegetation Control or Vegetation Regrowth Prevention
1.E. Subsurface and Surface Drainage for Recreational Areas
2.A. Tennis Court Orientation
2.B. Tennis Court Dimensions and Related Measurements

ASTM specifications are available from
American Society of Testing Materials (ASTM)
100 Barr Harbor Drive
West Conshohocken, PA 19428
610-832-950

NOTICE: These Construction Guidelines are for use by architects, engineers, contractors, tennis court and running track owners. Parties not experienced in tennis court or running track construction are advised to consult a qualified contractor, consultant and/or design professional. Experienced contractors, consultants and/or design professionals can be identified through the U. S. Tennis Court and Track Builders Association. Due to changing construction technology and techniques, only the most recent version of these Guidelines should be used. Variances in climate, soil conditions, topography and other factors may make these Guidelines unsuitable for certain projects.

Copyright © 1998 by U.S. Tennis Court and Track Builders Association. All Rights Reserved.