Guide to Design Detailing to Mitigate Cracking

Description

This guide addresses how to reduce potential cracking in reinforced concrete buildings in the design process through judicious consideration of building layout, selection of appropriate connections and joint types, and use of good rein-forcement details. Each member within a structure may be subject to different types of cracks. Once the building design is developed, the type of framing system and its geometry selected, and appropriate code-required loads considered, it is then possible for the engineer to understand and identify the possible predominate crack development, crack types, and crack locations for each member within the structure. Predicting possible crack development for members within a building typically allows application of appropriate design details to mitigate and control cracking. Effective detailing of concrete members can improve strength, serviceability (deflection and durability), and aesthetics of a concrete structure.

The terms “crack mitigation” and “crack control” as used in this document have distinct meanings. Crack mitigation involves measures that are intended to prevent cracking from occurring. This includes concepts intended to minimize or eliminate restraint, such as consideration of building layout, the use of connection or element releases, or both. Crack control involves measures that are intended to control where cracks occur, or to limit the width and spacing of cracks. Crack control approaches include the use of joints and reinforcement detailing.

The term “design details” in this document is a broad term intended to include all design measures intended to mitigate and control cracking.Some of the crack mitigation and control measures described in this document involve reinforcement details and other requirements that may already be required by the Building Code for structural reasons.