PTI DC10.3 PDF

Purpose and scope

This manual has been developed to provide guidance for owners, licensed design professionals (LDPs), builders, contractors, and field personnel involved in the design, installation, stressing, and finishing of unbonded single strand post-tensioning systems used in the construction of post-tensioned (PT) concrete courts.

In addition, this manual provides information regarding the proper maintenance procedures required during and after construction that are essential to the long-term performance of any concrete slab-on-ground. For the successful performance of a concrete slab, it is important that these procedures be understood and that a proper maintenance program be developed by the contractor, who will in turn pass it along to the owner. Proper drainage around the perimeter of any concrete slab supported by the ground is critical if the concrete slab is to perform its intended function over its expected service life.

It should be understood that while the details and recommendations presented in this manual are intended to represent generally accepted industry practice, the practices of individual companies on specific items (in particular, procedures for the operation of stressing equipment) may vary from the details and recommendations presented herein. In the event of any conflict between this manual and the contract documents or written instructions from the post-tensioning supplier, the contract documents or written instructions should always govern.

This manual is for the design, installation, stressing, and finishing of unbonded single strand post-tensioning systems used in the construction of PT concrete courts (Fig. 1.1) and does not cover the geotechnical or structural aspects for the design of PT concrete courts. Running tracks are longer than typical PT concrete courts and are not included in this document. Readers are directed to the following documents issued by the Post-Tensioning Institute (PTI) Slab-on-Ground Committee that relate to these aspects of the design of PT concrete courts:

• PTI DC10.5, Standard Requirements for Design and Analysis of Shallow Post-Tensioned Concrete Foundations on Expansive Soils

• PTI DC10.1, Design of Post-Tensioned Slabs-on-Ground

• PTI DC10.2, Construction and Maintenance Manual for Post-Tensioned Slab-on-Ground Foundations

• PTI M10.6, Specifications for Unbonded Single Strand Tendons Used for Slab-on-Ground Construction

Post-tensioned concrete has been found to be economical and effective in the construction of concrete courts. In its Tennis Court Construction Guidelines,1 the American Sports Builders Association (ASBA) states that “post-tensioned concrete slabs are the preferred method of concrete court construction.” Post-tensioned concrete courts provide the additional advantages of reducing or eliminating control joints, and resisting and controlling cracking, as a result of the compression introduced into the concrete by the PT tendons.

Factors that owners consider in selecting construction methods include player preference, climate, construction costs, maintenance costs, and repair costs. According to the ASBA, consideration should be given to the advantages of a strong durable playing surface that can take some abuse without damage.

Post-tensioned concrete provides a sturdy, durable playing surface that will withstand normal use and is substantially less susceptible to the effects of climate (heat, cold, rain, and snow) and soil movements than an asphalt court. When properly designed and constructed, a PT concrete court is relatively nonporous, provides a smooth surface and therefore needs limited maintenance, and has an extended useful life. Post-tensioned concrete provides a non-discoloring surface, has controllable ball skid length, and can receive many types of playing-surface topping systems.

A PT concrete court slab will typically have a higher flexural capacity as compared to a slab of the same thickness reinforced with nonprestressed reinforcing steel or welded-wire mesh. The use of single-strand unbonded tendons is a very cost-effective method of reinforcing concrete. The presence of PTI-certified suppliers, and installation contractors around the country helps to ensure the consistency and economy of this type of PT concrete construction. In addition, prequalification of post-tensioning material suppliers and installers can be accomplished by incorporating the certification requirements discussed in Section 15.2 herein.

ACI 318-19, Building Code for Structural Concrete, specifically excludes ground supported slab design and is therefore not applicable to the design of PT concrete courts. Design should be based on the recommendations of this document. The use of a post-tensioned uniform thickness slab designed with the methods discussed in this document may help mitigate the effects of expansive or compressible soils. The use of a PT concrete slab as described herein will minimize the effects of minor sub-grade defects (that is, small voids can be spanned to a greater extent than with other types of courts) but it is not intended to be a slab that is stiffened to the point of completely resisting the movements of expansive or compressible soils.

The geometry of a slab, and the various elements that can restrain a slab and prevent it from shortening under a prestressing force, play a critical role in the successful construction of PT concrete courts. The possible configurations are too numerous to address on an individual basis. However, sound engineering judgment and experience should be used in conjunction with these guidelines.