ACI 369.1-17

This standard provides retrofit and rehabilitation criteria for reinforced concrete buildings based on results from the most recent research on the seismic performance of existing concrete buildings. The intent of this standard is to provide a continuously updated resource document for modifications to Chapter 10 of ASCE 41-17, similar to how the National Earthquake Hazards Reduction Program (NEHRP) Recommended Seismic Provisions produced by the Federal Emergency Management Agency (FEMA) (FEMA 450) have served as source documents for the International Building Code (IBC) and its predecessor building codes. Specifically, this version of ACI 369.1 serves as the basis for Chapter 10, “Concrete,” of ASCE 41-17.

This standard should be used in conjunction with Chapters 1 through 7 of ASCE 41-17. Chapter 1 of ASCE 41-17 provides general requirements for evaluation and retrofit, including the selection of performance objectives and retrofit strategies. Chapter 2 of ASCE 41-17 defines performance objectives and seismic hazards. Chapter 3 of ASCE 41-17 provides the requirements for evaluation and retrofit, including treating as-built information and selecting the appropriate screening procedures. Chapter 4 of ASCE 41-17 summarizes Tier 1 screening procedures, while Chapters 5 and 6 summarize Tier 2 deficiency-based procedures and Tier 3 systematic procedures for evaluation and retrofit, respectively. Chapter 7 of ASCE 41-17 details analysis procedures referenced in ACI 369.1, including linear and nonlinear analysis procedures, acceptance criteria, and alternative methods for determining modeling parameters and acceptance criteria. Chapter 8 of ASCE 41-17 provides geotechnical engineering provisions for building foundations and assessment of seismic-geologic site hazards. References to these chapters can be found throughout the standard. The design professional is referred to FEMA 547 for detailed information on seismic rehabilitation measures for concrete buildings. Repair techniques for earthquake-damaged concrete components are not included in ACI 369.1. The design professional is referred to FEMA 306, FEMA 307, and FEMA 308 for information on evaluation and repair of damaged concrete wall components.

This standard does not provide modeling procedures, acceptance criteria, and rehabilitation measures for concrete-encased steel composite components. Future versions will provide provision updates for concrete moment frames and will add provisions for concrete components and systems omitted in the present version of the standard.