Q.: We would like to know if there have been any published data or surveys made of buildings where particularly long distances between joints have been built and proved effective or otherwise.

A.: Control joints were spaced 44 feet on centers in the Military Personnel Records Center, St. Louis, Missouri, a 282- by 728-foot, 6-story flat slab building built in 1956. The building was built with 22- by 22-foot bays with control joints at every second bay. Concrete was placed in checkerboard fashion, allowing 48 hours between placement of adjacent sections. Three-foot-long Number 4 dowels near the tops of the slabs cross the joints 12 inches on centers and the slab reinforcement also crosses the joints.

The General Accounting Office Building built in 1951 in Washington, D.C., an 8-story flat slab building 389 feet by 638 feet, built with 25- by 25-foot bays, has control joints 50 feet on centers.

No expansion joints were used in the Los Angeles Union Terminal 7-story flat slab warehouse, 100 feet by 550 feet, or in its 4-story 100- by 440-foot building, neither of which showed any distress from lack of expansion joints when inspected in 1958 at ages of 40 to 50 years.

The minimizing of expansion joints in the design of the first building is discussed in the article by Earl B. Cohn and W A. Wahl, "Military Personnel Records Center Built Without Expansion Joints," Journal of the American Concrete Institute, June 1958, page 1103.