Q.: A project consisting of three tennis courts and supplementary aprons is scheduled for bidding. The job is now set up as a blacktop paving project but the engineer will accept an alternate proposal for a concrete court system provided he can be assured of how the construction joints will be built so as not to have a ridge occur between one pour and another.

Are there any standard methods, recommendations, or drawings as to how the joints should be constructed, and where they should be located?

A.: It is the recommendation of the Portland Cement Association that no joints be used within the court itself, but that enough steel be used to keep hairline cracks tightly closed. For this purpose they recommend using Number 5 reinforcing bars at 12 inches on centers in each direction for a 5-inch-thick slab, or at 15 inches on centers for a 4-inch-thick slab. These should be located at mid-depth of the slab and be supported every 4 inches by bolsters or every 3 inches by concrete bricks. If necessary to construct the court in two parts, an expansion joint can be used under the net. Expansion joints should also be used between adjacent courts. Details and construction practices are given in the 6-page article, "How to Design and Build Concrete Tennis Courts," published in our June 1977 issue, page 317.

Still more complete information is provided in Reinforced Tennis Courts, Publication IS199T, available for purchase from the Portland Cement Association, 5420 Old Orchard Road, Skokie, Illinois 60076.