Three Myths About Contraction Joints in Residential Slabs

摘要

First, American Concrete Institute (ACI) 332-14, Residential Code Requirements for Structural Concrete, requires contraction joints (also called control joints) and provides a table to determine spacing for plain and reinforced concrete containing up to 0.5% reinforcement (reproduced here as Table 1 on page 32). Most residential slabs contain reinforcement of less than 0.1%. (For example, 0.1% reinforcement in a 4-inch slab is #3 bars in both directions at 24 inches.)