scope:

This code sets forth requirements for the seismic evaluation and retrofit of concrete components of the seismic-force-resisting system of an existing building. These requirements apply to existing concrete components, retro-fitted concrete components, and new concrete components. Provisions of this code do not apply to concrete-encased steel composite components.

Chapter 2 specifies data collection procedures for obtaining material properties and performing condition assessments. Chapter 3 provides general analysis and design requirements for concrete components. Chapters 4 through 9 provide modeling procedures, component strengths, acceptance criteria, and retrofit measures for cast-in-place and precast concrete moment frames, concrete frames with masonry infills, cast-in-place and precast concrete structural walls, and concrete-braced frames. Chapters 10 through 12 provide modeling procedures, strengths, acceptance criteria, and retrofit measures for concrete diaphragms and concrete foundation systems.

These requirements were developed based on the best knowledge of the seismic performance of existing concrete buildings at the time of publication. These requirements are not intended to restrict the licensed design professional from using new information that becomes available before the issuance of the next edition of this code. Such new information can include tests conducted to address specific building conditions.

This code provides short descriptions of potential seismic retrofit measures for each concrete building system. The licensed design professional is referred to FEMA 547 for detailed information on seismic retrofit measures for concrete buildings. Repair techniques for earthquake-damaged concrete components are not included in this code. The licensed design professional is referred to FEMA 306, FEMA 307, and FEMA 308 for information on evaluation and repair of damaged concrete wall components.

Concrete-encased steel-composite components behave differently from concrete sections reinforced with steel reinforcement. Concrete-encased steel-composite components frequently behave as over-reinforced sections. This type of component behavior was not represented in the data sets used to develop the force-deformation modeling relationships and acceptance criteria in this code, and is not covered herein.

To preserve historic buildings, care should be exercised in selecting the appropriate retrofit approaches and techniques for application.