ACI 408R-03 (R2012) PDF Download

ACI 408R-03 (R2012) is a standard that focuses on the bond and development of straight reinforcing bars in tension in reinforced concrete structures. The report discusses the factors that influence bond strength, such as concrete cover and bar spacing, bar size, transverse reinforcement, bar geometry, concrete properties, steel stress and yield strength, bar surface condition, bar casting position, development and splice length, distance between spliced bars, and concrete consolidation. It also provides descriptive equations and design provisions for development and splice strength based on a large database of test results.

The report highlights that the contribution of concrete strength to bond is best represented by the compressive strength raised to the power of 1/4, while the contribution of transverse reinforcement to added bond strength is best represented by the compressive strength raised to a power between 3/4 and 1.0. The standard suggests using the lower value in the proposed design equations. It also points out that certain provisions for bond in ACI 318-02 are not always conservative and recommends improvements.