ACI CODE-369.1-22: Seismic Evaluation and Retrofit of Existing Concrete Buildings—Code and Commentary

Description

This code 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 code is to provide provisions related to concrete material and concrete members, including material testing criteria, modeling parameters, and acceptance criteria for use within the ASCE 41 framework, 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. Starting in the 2023 edition, ASCE 41 references ACI 369.1 directly for concrete-related provisions. Chapter and section numbers of ASCE 41 cited in ACI 369.1 correspond to ASCE 41-17 unless otherwise noted.

This code should be used in conjunction with Chapters 1 through 8 of ASCE 41-17 and applicable sections of the ACI 318-19 Building Code. Chapter 1 of ASCE 41 provides general requirements for evaluation and retrofit, including the selection of performance objectives and retrofit strategies. Chapter 2 of ASCE 41 defines performance objectives and seismic hazards. Chapter 3 of ASCE 41 provides requirements for evaluation and retrofit, including treating as-built information and selecting appropriate screening procedures. Chapter 4 of ASCE 41 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 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 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 licensed design professional is referred to ACI 562, FEMA 306, FEMA 307, and FEMA 308 for information on evaluation and repair of damaged concrete wall components.

This code does not provide modeling procedures, acceptance criteria, or rehabilitation measures for concrete-encased steel composite components.

Keywords:

acceptance criteria; building; deformation-controlled; dynamic analysis; earthquake; force-controlled; modeling parameters; nonlinear analysis; retrofit; seismic evaluation, seismic assessment; structural evaluation.

Document Details

Author: ACI Committee 369S

Publication Year: 2023

Pages: 125

Categories: Codes

Formats: Printed Document or Protected PDF/Web View

Table of Contents

INTRODUCTION, p. 2

CHAPTER 1—GENERAL, p. 5

1.1—Scope, p. 5

CHAPTER 2—MATERIAL PROPERTIES AND CONDITION ASSESSMENT, p. 6

2.1—General, p. 6

2.2—Properties of in-place materials and components, p. 7

2.3—Condition assessment, p. 15

2.4—Knowledge factor, p. 17

2.5—Properties of new materials, p. 18

CHAPTER 3—GENERAL ASSUMPTIONS AND REQUIREMENTS, p. 19

3.1—Modeling and design, p. 19

3.2—Strength and deformability, p. 29

3.3—Flexure and axial loads, p. 30

3.4—Shear and torsion, p. 33

3.5—Development and splices of reinforcement, p. 34

3.6—Connections to existing concrete, p. 36

3.7—Retrofit measures, p. 39

CHAPTER 4—CONCRETE MOMENT FRAMES, p. 40

4.1—Types of concrete moment frames, p. 40

4.2—Reinforced concrete beam-column moment frames, p. 41

4.3—Post-tensioned concrete beam-column moment frames, p. 59

4.4—Slab-column moment frames, p. 60

CHAPTER 5—PRECAST CONCRETE FRAMES, p. 67

5.1—Types of precast concrete frames, p. 67

5.2—Precast concrete frames expected to resist seismic forces, p. 67

5.3—Precast concrete frames not expected to resist seismic forces directly, p. 68

CHAPTER 6—CONCRETE FRAMES WITH INFILLS, p. 70

6.1—Types of concrete frames with infills, p. 70

6.2—Concrete frames with masonry infills, p. 70

6.3—Concrete frames with concrete infills, p. 74

CHAPTER 7—CONCRETE STRUCTURAL WALLS, p. 77

7.1—Types of concrete structural walls and associated components, p. 77

7.2—Strength of reinforced concrete structural walls, wall segments, and coupling beams, p. 79

7.3—Linear static and dynamic procedures for reinforced concrete structural walls and wall segments, p. 81

7.4—Nonlinear static and dynamic procedures for reinforced concrete structural walls and wall segments , p. 87

7.5—Linear static and dynamic procedures for reinforced concrete coupling beams, p. 93

7.6—Nonlinear static and dynamic procedures for reinforced concrete coupling beams, p. 95

7.7—Retrofit measures for reinforced concrete structural walls, wall segments, and coupling beams, p. 97

CHAPTER 8—PRECAST CONCRETE STRUCTURAL WALLS, p. 99

8.1—Types of precast structural walls, p. 99

8.2—Precast concrete structural walls and wall segments, p. 100

CHAPTER 9—CONCRETE-BRACED FRAMES, p. 105

9.1—Types of concrete-braced frames, p. 105

9.2—General, p. 105

9.3—Stiffness of concrete-braced frames, p. 105

9.4—Strength of concrete-braced frames, p. 106

9.5—Acceptance criteria for concrete-braced frames, p. 106

9.6—Retrofit measures for concrete-braced frames, p. 107

CHAPTER 10—CAST-IN-PLACE CONCRETE DIAPHRAGMS, p. 108

10.1—Components of cast-in-place concrete diaphragms, p. 108

10.2—Analysis, modeling, and acceptance criteria for cast-in-place concrete diaphragms, p. 108

10.3—Retrofit measures for cast-in-place concrete diaphragms, p. 109

CHAPTER 11—PRECAST CONCRETE DIAPHRAGMS, p. 110

11.1—Components of precast concrete diaphragms, p. 110

11.2—Analysis, modeling, and acceptance criteria for precast concrete diaphragms, p. 110

11.3—Retrofit measures for precast concrete diaphragms, p. 110

CHAPTER 12—CONCRETE FOUNDATIONS, p. 111

12.1—Types of concrete foundations, p. 111

12.2—Analysis of existing concrete foundations, p. 112

12.3—Evaluation of existing condition, p. 112

12.4—Retrofit measures for concrete foundations, p. 112

CHAPTER 13—NOTATION AND DEFINITIONS, p. 115

13.1—Notation, p. 115

13.2—Definitions, p. 119

CHAPTER 14—REFERENCES, p. 121

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