Seismic Retrofit of Existing Reinforced Concrete Buildings

Cover
Title Page
Copyright Page
Contents
Foreword by Rui Pinho
Acknowledgments
Chapter 1 Introduction
1.1 General
1.2 Why Do Old RC Buildings Need Strengthening?
1.3 Main Differences Between Assessment and Design Methodologies
1.4 Whom Is this Book For?
1.5 Main Standards for the Seismic Evaluation of Existing Structures
References
Chapter 2 Know Your Building: The Importance of Accurate Knowledge of the Structural Configuration
2.1 Introduction
2.2 What Old RC Buildings Are Like
2.2.1 Lack of Stirrups
2.2.2 Unconventional Reinforcement in the Members
2.2.3 Large, Lightly Reinforced Shear Walls or Lack of Shear Walls
2.2.4 Lap Splices
2.2.5 Corrosion
2.2.6 Geometry: Location of Structural Members
2.2.7 Geometry: Bad Alignment of the Columns
2.2.8 Geometry: Arbitrary Alterations During Construction or During the Building’s Lifetime
2.2.9 Bad Practices with Respect to the Mechanical and Electrical Installations
2.2.10 Soft Ground Stories
2.2.11 Short Columns
2.2.12 Different Construction Methods
2.2.13 Foundation Conditions
2.2.14 Discussion
2.2.15 One Final Example
2.3 How Come Our Predecessors Were So Irresponsible?
2.4 What the Codes Say – Knowledge Level and the Knowledge Factor
2.5 Final Remarks
References
Chapter 3 Measurement of Existing Buildings, Destructive and Nondestructive Testing
3.1 Introduction
3.2 Information Needed for the Measured Drawings
3.3 Geometry
3.4 Details – Reinforcement
3.5 Material Strengths
3.6 Concrete Tests – Destructive Methods
3.7 Concrete Tests – Nondestructive Methods, NDT
3.7.1 Rebound Hammer Test
3.7.2 Penetration Resistance Test
3.7.3 Pull-Off Test
3.7.4 Ultrasonic Pulse Velocity Test, UPV
3.8 Steel Tests
3.9 Infill Panel Tests
3.10 What Is the Typical Procedure for Monitoring an Existing Building?
3.11 Final Remarks
References
Chapter 4 Methods for Strengthening Reinforced Concrete Buildings
4.1 Introduction
4.2 Literature Review
4.3 Reinforced Concrete Jackets
4.3.1 Application
4.3.2 Advantages and Disadvantages
4.3.3 Design Issues: Modeling, Analysis, and Checks
4.4 Shotcrete
4.4.1 Introduction
4.4.2 Dry Mix vs. Wet Mix Shotcrete
4.4.3 Advantages and Disadvantages of Shotcrete
4.4.4 What Is It Actually Called – Shotcrete or Gunite?
4.4.5 Materials, Proportioning, and Properties
4.4.6 Mix Proportions for the Dry-Mix Process
4.4.7 Equipment and Crew
4.4.8 Curing and Protection
4.4.9 Testing and Evaluation
4.5 New Reinforced Concrete Shear Walls
4.5.1 Application
4.5.2 Foundation Systems of New Shear Walls
4.5.3 Advantages and Disadvantages
4.5.4 Design Issues: Modeling and Analysis
4.6 RC Infilling
4.6.1 Application
4.6.2 Advantages and Disadvantages
4.7 Steel Bracing
4.7.1 Application
4.7.2 Advantages and Disadvantages
4.7.3 Design Issues: Modeling, Analysis, and Checks
4.8 Fiber-Reinforced Polymers (FRPs)
4.8.1 FRP Composite Materials
4.8.2 FRP Composites in Civil Engineering and Retrofit
4.8.3 FRP Composite Materials
4.8.4 FRP Wrapping
4.8.5 FRP Laminates
4.8.6 Near Surface Mounted FRP Reinforcement
4.8.7 FRP Strings
4.8.8 Sprayed FRP
4.8.9 Anchoring Issues
4.8.10 Advantages and Disadvantages of FRP Systems
4.8.11 Design Issues
4.9 Steel Plates and Steel Jackets
4.9.1 Advantages and Disadvantages
4.9.2 Design Issues
4.10 Damping Devices
4.11 Seismic Isolation
4.11.1 Type of Base Isolation Systems
4.11.2 Advantages and Disadvantages
4.11.3 Design Issues
4.12 Selective Strengthening and Weakening Through Infills
4.13 Strengthening of Infills
4.13.1 Glass or Carbon FRPs
4.13.2 Textile Reinforced Mortars TRM
4.13.3 Shotcrete
4.14 Connecting New and Existing Members
4.14.1 Design Issues
4.15 Strengthening of Individual Members
4.15.1 Strengthening of RC Columns or Walls
4.15.2 Strengthening of RC Beams
4.15.3 Strengthening of RC Slabs
4.15.4 Strengthening of RC Ground Slabs
4.16 Crack Repair – Epoxy Injections
4.17 Protection Against Corrosion, Repair Mortars, and Cathodic Protection
4.18 Foundation Strengthening
4.19 Concluding Remarks Regarding Strengthening Techniques
4.20 Evaluation of Different Seismic Retrofitting Solutions: A Case Study
4.20.1 Building Configuration
4.20.2 Effects of the Infills on the Structural Behavior
4.20.3 Strengthening with Jacketing
4.20.4 Strengthening with New RC Walls (Entire Building Height)
4.20.5 Strengthening with New RC Walls (Ground Level Only)
4.20.6 Strengthening with Braces
4.20.7 Strengthening with FRP Wrapping
4.20.8 Strengthening with Seismic Isolation
4.20.9 Comparison of the Methods
References
Chapter 5 Criteria for Selecting Strengthening Methods – Case Studies
5.1 Things Are Rarely Simple
5.2 Criteria for Selecting Strengthening Method
5.3 Basic Principles of Conceptual Design
5.4 Some Rules of Thumb
5.5 Case Studies
5.5.1 Case Study1: Seismic Upgrade of a Five-Story Hotel
5.5.2 Case Study2: Seismic Upgrade of a Four-Story Hotel
5.5.3 Case Study 3: Seismic Upgrade of a Four-Story Hotel
5.5.4 Case Study 4: Seismic Upgrade of a Three-Story Residential Building
5.5.5 Case Study 5: Seismic Upgrade of a Three-Story Residential Building for the Addition of Two New Floors
5.5.6 Case Study 6: Seismic Strengthening of an 11-Story Building
5.5.7 Case Study 7: Seismic Strengthening of a Five-Story Building
5.5.8 Case Study 8: Seismic Strengthening of a Three-Story Building
5.5.9 Case Study 9: Strengthening a Building Damaged by a Severe Earthquake
5.5.10 Case Study 10: Strengthening of an 11-Story Building
5.5.11 Case Study 11: Strengthening of a Two-Story Building with Basement
5.5.12 Case Study 12: Strengthening of a Weak Ground Story with FRP Wraps
5.5.13 Case Study 13 (Several Examples): Strengthening of RC Slabs
5.5.14 Case Study 14: Strengthening of a Ground Slab
5.5.15 Case Study 15: Strengthening of Beam That Has Failed in Shear
5.5.16 Case Study 16: Demolition and Reconstruction of a RC Beam
5.5.17 Bonus Case Study 1: Strengthening of an Industrial Building
5.5.18 Bonus Case Study 2: Strengthening of an Industrial Building
5.5.19 Bonus Case Study 3: Strengthening of a Residential Building
References
Chapter 6 Performance Levels and Performance Objectives
6.1 Introduction
6.1.1 Selection of Performance Objectives in the Design of New Buildings
6.1.2 Selection of Performance Objectives in the Assessment of Existing Buildings
6.2 Seismic Assessment and Retrofit Procedures
6.2.1 Seismic Assessment Procedures
6.2.2 Seismic Retrofit Procedures
6.3 Understanding Performance Objectives
6.3.1 Target-Building Performance Levels
6.3.2 Seismic Hazard Levels
6.3.3 Performance Objectives
6.3.4 Eurocode 8, Part 3, and Other Standards
6.3.5 The Rationale for Accepting a Lower Performance Level for Existing Buildings
6.4 Choosing the Correct Performance Objective
References
Chapter 7 Linear and Nonlinear Methods of Analysis
7.1 Introduction
7.2 General Requirements
7.2.1 Loading Combinations
7.2.2 Multidirectional Seismic Effects
7.2.3 Accidental Torsional Effects
7.3 Linear Static Procedure
7.4 Linear Dynamic Procedure
7.5 Nonlinear Structural Analysis
7.5.1 Nonlinear Structural Analysis in Engineering Practice
7.5.2 Challenges Associated with Nonlinear Analysis
7.5.3 Some Theoretical Background
7.5.6 Final Remarks on Nonlinear Analysis
7.6 Nonlinear Static Procedure
7.6.1 Pushover Analysis
7.6.2 Information Obtained with Pushover Analysis
7.6.3 Theoretical Background on Pushover Analysis
7.6.4 Target Displacement
7.6.5 Applying Forces vs. Applying Displacements
7.6.6 Controlling the Forces or the Displacements
7.6.7 Control Node
7.6.8 Lateral Load Patterns
7.6.9 Pushover Analysis Limitations
7.7 Nonlinear Dynamic Procedure
7.7.1 Information Obtained with Nonlinear Dynamic Analysis
7.7.2 Selecting and Scaling Accelerograms
7.7.3 Advantages and Disadvantages of Nonlinear Dynamic Analysis
7.8 Comparative Assessment of Analytical Methods
7.8.1 Advantages and Disadvantages of the Analytical Methods
7.8.2 Selection of the Best Analysis Procedure for Structural Assessment
References
Chapter 8 Structural Modeling in Linear and Nonlinear Analysis
8.1 Introduction
8.2 Mathematical Modeling
8.3 Modeling of Beams and Columns
8.3.1 Material Inelasticity
8.3.2 Geometric Nonlinearities
8.3.3 Modeling of Structural Frame Elements
8.3.3.1 Concentrated Plasticity Elements
8.3.3.2 Advantages and Disadvantages of Concentrated Plasticity Models
8.3.3.3 Distributed Plasticity Elements – Fiber Modeling
8.3.3.4 Types of Distributed Plasticity Elements
8.3.3.5 Advantages and Disadvantages of Distributed Plasticity Models
8.3.3.6 Considerations Regarding the Best Frame Model for Structural Members
8.4 Modeling of Shear Walls
8.5 Modeling of Slabs
8.6 Modeling of Stairs
8.7 Modeling of Infills
8.8 Modeling of Beam-Column Joints
8.9 Modeling of Bar Slippage
8.10 Shear Deformations
8.11 Foundation Modeling
8.12 How Significant Are Our Modeling Decisions?
References
Chapter 9 Checks and Acceptance Criteria
9.1 Introduction
9.2 Primary and Secondary Members
9.3 Deformation-Controlled & Force-Controlled Actions
9.4 Expected Vs. Lower-Bound Material Strengths
9.5 Knowledge Level and Knowledge Factor
9.6 Capacity Checks
9.6.1 Capacity Checks for Linear Methods – ASCE 41
9.6.2 Capacity Checks for Nonlinear Methods – ASCE 41
9.7 Main Checks to Be Carried Out in an Assessment Procedure
9.7.1 Bending Checks
9.7.2 Shear Checks
References
Chapter 10 Practical Example: Assessment and Strengthening of a Six-Story RC Building
10.1 Introduction
10.2 Building Description
10.3 Knowledge of the Building and Confidence Factor
10.3.1 Geometry
10.3.2 Reinforcement
10.3.3 Material Strengths
10.4 Seismic Action and Load Combinations
10.5 Structural Modeling
10.6 Eigenvalue Analysis
10.7 Nonlinear Static Procedure
10.7.1 Lateral Load Patterns
10.7.2 Selection of the Control Node
10.7.3 Capacity Curve and Target Displacement Calculation
10.7.4 Safety Verifications
10.7.5 Chord Rotation Checks
10.7.6 Example of the Calculation of Chord Rotation Capacity
10.7.7 Shear Checks
10.7.8 Example of the Calculation of Shear Capacity
10.7.9 Beam-Column Joint Checks
10.7.10 Example of the Checks for Beam-Column Joints
10.8 Strengthening of the Building
10.8.1 Strengthening with Jackets
10.8.2 Designing the Interventions
10.8.3 Deliverables
10.8.4 Strengthening with Shear Walls
References
Appendix A Standards and Guidelines
A.1 Eurocodes
A.1.1 Performance Requirements
A.1.2 Information for Structural Assessment
A.1.3 Safety Factors
A.1.4 Capacity Models for Assessment and Checks
A.1.5 Target Displacement Calculation in Pushover Analysis
A.2. ASCE 41-17
A.2.1 Performance Requirements
A.2.2 Information for Structural Assessment
A.2.3 Safety Factors
A.2.4 Capacity Models for Assessment and Checks
A.2.5 Target Displacement Calculation in the Nonlinear Static Procedure
References
Appendix B Poor Construction and Design Practices in Older Buildings
B.1 Stirrup Spacing
B.2 Lap Splices
B.3. Member Alignment
B.4 Pipes inside RC Members
B.5 Bad Casting of Concrete
B.6 Footings
Appendix C Methods of Strengthening
C.1 Reinforced Concrete Jackets
C.2 New Shear Walls
C.3 Fiber-Reinforced Polymers
C.3.1 FRP Wrapping of Columns
C.3.2 FRP Fabrics in Slabs
C.3.3 FRP Wraps for Shear Strengthening
C.3.4 FRP Laminates
C.3.5 FRP Strings
C.4 Steel Braces
C.5 Steel Jackets
C.6 Steel Plates
C.7 Infills
C.8 Foundations
C.9 Dowels and Anchorages
C.10 Demolition with Concrete Cutting
C.11 Reinforcement Couplers
C.12 Epoxy Injections
Index
EULA