Seismic Design, Assessment and Retrofitting of Concrete Buildings base on Eurocode 8 (KEBT0008)

Seismic Design, Assessment and Retrofitting of Concrete Buildings base on Eurocode 8, CONTENTS:      

1 General Principles for the Design of Concrete Buildings for Earthquake Resistance

1.1 Seismic Performance Requirements for Concrete Buildings

1.1.1 The Current Situation: Emphasis on Life Safety

1.1.2 Performance-Based Requirements

1.1.3 Performance-Based Seismic Design, Assessment or Retrofitting According to Eurocode 8

1.1.4 Performance-Based Design Aspects of Current US Codes

1.2 Force-Based Seismic Design

1.2.1 Force-Based Design for Energy-Dissipation and Ductility

1.2.2 Force-Based Dimensioning of Ductile “Dissipative Zones” and of Other Regions of Members . 11

1.3 Control of Inelastic Seismic Response Through Capacity Design

1.3.1 The Rationale of Capacity Design

1.3.2 The Importance of a Stiff and Strong Vertical Spine inaBuilding

1.3.3 Overview of Capacity-Design-Based Seismic Design Procedure

1.3.4 Capacity Design of Columns in Flexure

1.3.5 Design of Ductile Walls in Flexure

1.3.6 Capacity Design of Members Against Pre-emptive Shear Failure

1.4 The Options of Strength or Ductility in Earthquake-Resistant Design

1.4.1 Ductility as an Alternative to Strength

1.4.2 The Trade-Off Between Strength and Ductility – Ductility Classification in Seismic Design Codes

1.4.3 Behaviour Factor q of Concrete Buildings Designed for Energy Dissipation

2 Conceptual Design of Concrete Buildings for Earthquake Resistance

2.1 Principles and Rules for the Conceptual Design Of Building Structures

2.1.1 The Importance of Conceptual Design for Earthquake Resistance

2.1.2 Fundamental Attributes of a Good Structural Layout

2.1.3 Clear Lateral-Load-Resisting System

2.1.4 Simplicity and Uniformity in the Geometry of the Lateral-Load-Resisting System

2.1.5 Symmetry and Regularity in Plan

2.1.6 Torsional Stiffness About a Vertical Axis

2.1.7 Geometry, Mass and Lateral Stiffness Regular inElevation

2.1.8 Lateral Resistance Characterised by Regularity inElevation

2.1.9 Redundancy of the Lateral Load Resisting System

2.1.10 Continuity of the Force Path, Without Local Concentrations of Stresses and Deformation Demands

2.1.11 Effective Horizontal Connection of Vertical Elements by Floor Diaphragms at All Floor Levels

2.1.12 Minimal Total Mass

2.1.13 Absence of Adverse Effects of Elements Not Considered As Part of the Lateral-Load Resisting System and of Masonry Infills in Particular

2.2 Frame, Wall or Dual Systems for Concrete Buildings

2.2.1 Seismic Behaviour and Conceptual Design of FrameSystems

2.2.2 Seismic Behaviour and Conceptual Design of WallSystems 2.2.3 DualSystems ofFrames andWalls

2.2.4 The Special Case of Flat-Slab Frames

2.3 Conceptual Design of Shallow (Spread) Foundation Systems for Earthquake-Resistance

2.3.1 Introduction

2.3.2 Foundation of the Entire Building at the Same Level

2.3.3 The Options for Shallow Foundation Systems

2.3.4 Capacity Design of the Foundation

2.3.5 A Look into the Future for the Seismic Design of Foundations

2.4 Examples of Seismic Performance of Buildings with Poor Structural Layout

2.4.1 Introductory Remarks

2.4.2 Collapse of Wing of Apartment Building in the Athens 1999 Earthquake

2.4.3 Collapse of Four-Storey Hotel Building in the Aegio (GR) 1995 Earthquake

2.4.4 Collapse of Six-Storey Apartment Building in the Aegio (GR) 1995 Earthquake

3 Concrete Members Under Cyclic Loading

3.1 TheMaterials andTheir Interaction

3.1.1 ReinforcingSteel

3.1.2 The Concrete

3.1.3 Interaction Between Reinforcing Bars and Concrete

3.1.4 Concluding Remarks on the Behaviour of Concrete Materials and Their Interaction Under Cyclic Loading

3.2 Concrete Members

3.2.1 The Mechanisms of Force Transfer in Concrete Members: Flexure, Shear and Bond

3.2.2 Flexural Behaviour at the Cross-Sectional Level

3.2.3 FlexuralBehaviour at theMemberLevel

3.2.4 Behaviour of Members Under Cyclic Shear

3.2.5 Cyclic Behaviour of Squat Members, Controlled by Flexure-Shear Interaction

3.3 Joints inFrames

3.3.1 Force Transfer Mechanisms in Concrete Joints: Bond and Shear

3.3.2 The Bond Mechanism of Force Transfer in Joints

3.3.3 Force Transfer Within Joints Through the Shear Mechanism

4 Analysis and Modelling for Seismic Design or Assessment of Concrete Buildings

4.1 Scope of Analysis in Codified Seismic Design or Assessment

4.1.1 Analysis for thePurposes ofSeismicDesign

4.1.2 Analysis for Seismic Assessment and Retrofitting

4.2 TheSeismicAction for theAnalysis

4.2.1 Elastic Spectra

4.2.2 Design Spectrum for Forced-Based Design with Linear Analysis

4.3 Linear Static Analysis

4.3.1 Fundamentals and Conditions of Applicability

4.3.2 Fundamental Period and Base Shear

4.3.3 Pattern ofLateralForces

4.4 Modal Response Spectrum Analysis

4.4.1 Modal Analysis and Its Results

4.4.2 Minimum Number of Modes

4.4.3 Combination of Modal Results

4.5 Linear Analysis for the Vertical Seismic Action Component

4.5.1 When is the Vertical Component Important and Should Be Taken Into Account?

4.5.2 Special Linear Static Analysis Approach for the Vertical Component

4.6 Nonlinear Analysis

4.6.1 Nonlinear Static (“Pushover”) Analysis

4.6.2 Nonlinear Dynamic (Response- or Time-History) Analysis

4.6.3 Concluding Remarks on the Nonlinear Analysis Methods

4.7 Combination of the Maximum Effects of the Individual Seismic Action Components

4.7.1 The Two Options: The SRSS and the Linear Approximation

4.7.2 Combination of the Effects of the Seismic Action Components in Dimensioning forVectorialActionEffects

4.8 Analysis for Accidental Torsional Effects

4.8.1 Accidental Eccentricity

4.8.2 Estimation of the Effects of Accidental Eccentricity Through Linear Static Analysis

4.8.3 Combination of Accidental Eccentricity Effects Due to the Two Horizontal Components of the Seismic Action for Linear Analysis

4.8.4 Simplified Estimation of Accidental Eccentricity Effects in Eurocode 8 for Planwise Symmetric LateralStiffness andMass

4.8.5 Accidental Eccentricity in Nonlinear Analysis

4.9 Modeling of Buildings for Linear Analysis

4.9.1 TheLevel ofDiscretisation

4.9.2 Effective Elastic Stiffness of Concrete Members

4.9.3 Modelling of Beams and Columns

4.9.4 Special Modelling Aspects for Walls

4.9.5 Modelling of Floor Diaphragms

4.9.6 A Special Case in Modelling: Concrete Staircases

4.9.7 2nd-Order (P-Δ)Effects

4.9.8 Modelling of Masonry Infills

4.9.9 Modelling of Foundation Elements and of Soil Compliance

4.10 Modelling of Buildings for Nonlinear Analysis

4.10.1 Nonlinear Models for Concrete Members

4.10.2 Nonlinear Modelling of Masonry Infills

4.10.3 Modelling of Foundation Uplift

4.10.4 Special Provisions of Eurocode 8 for Nonlinear Analysis

4.10.5 Example Applications of Nonlinear Analysis in 3D and Comparison with Measured Dynamic Response

4.11 Calculation of Displacement and Deformation Demands

4.11.1 Estimation of Inelastic Displacements and Deformations Through Linear Analysis

4.11.2 Evaluation of the Capability of Linear Analysis to Predict Inelastic Deformation Demands

4.12 “Primary” V “Secondary Members” for Earthquake Resistance

4.12.1 Definition and Role of “Primary” and “Secondary Members”

4.12.2 Constraints on the Designation of Members as “Secondary”

4.12.3 Special Design Requirements for “Secondary Members” inNewBuildings

4.12.4 Guidance on the Use of the Facility of “Secondary Members”

4.12.5 Modelling of “Secondary Members” in the Analysis

5 Detailing and Dimensioning of New Buildings in Eurocode 8

5.1 Introduction

5.1.1 “Critical Regions” in Ductile Elements

5.1.2 Geometry, Detailing and Special Dimensioning Rules in Eurocode 8: An Overview

5.2 Curvature Ductility Requirements According to Eurocode 8

5.3 Detailing Rules for Local Ductility of Concrete Members

5.3.1 Minimum Longitudinal Reinforcement Throughout a Beam

5.3.2 Maximum Longitudinal Reinforcement Ratio in“CriticalRegions” ofBeams

5.3.3 Confining Reinforcement in “Critical Regions” of Primary Columns and Ductile Walls

5.3.4 Boundary Elements at Section Edges in “Critical Regions” of Ductile Walls

5.4 Detailing and Dimensioning of Beam-Column Joints

5.4.1 Maximum Diameter of Longitudinal Beam Bars Crossing or Anchored at Beam-Column Joints

5.4.2 Verification of Beam-Column Joints in Shear

5.5 Special Dimensioning Rules for Shear

5.5.1 Dimensioning of Shear Reinforcement in “CriticalRegions” ofBeams orColumns

5.5.2 Inclined Reinforcement Against Sliding Shear in “CriticalRegions” ofDCHBeams

5.5.3 Shear Verification of Ductile Walls of DC H

5.6 Systems of “Large Lightly Reinforced Walls” in Eurocode 8

5.6.1 Definitions

5.6.2 Dimensioning of “Large Lightly Reinforced Walls” for the ULS in Bending and Axial Force

5.6.3 Dimensioning of “Large Lightly Reinforced Walls” for the ULS in Shear

5.6.4 Detailing of the Reinforcement in “Large Lightly ReinforcedWalls”

5.7 Implementation of Detailed Design of a Building Structure

5.7.1 The Sequence of Operations in Detailed Design for Ductility

5.7.2 DetailedDesign ofBeamand Joints

5.7.3 DetailedDesign ofColumns

5.7.4 Detailed Design of Ductile Walls

5.8 ApplicationExamples

5.8.1 3-StoreyFrameBuilding onSpreadFootings

5.8.2 7-Storey Wall Building with Box Foundation and Flat Slab Frames Taken as Secondary Elements

6 Seismic Assessment and Retrofitting of Existing Concrete Buildings

6.1 Introduction

6.2 Seismic Vulnerability of Existing Concrete Buildings

6.2.1 System and Layout Aspects and Deficiencies

6.2.2 Common Deficiencies and Failure Modes of Concrete Members

6.3 The Predicament of Force-Based Seismic Assessment and Retrofitting

6.4 Seismic Performance Requirements and Criteria for ExistingorRetrofittedBuildings

6.5 Performance- and Displacement-Based Seismic Assessment and Retrofitting in Eurocode 8

6.5.1 Introduction

6.5.2 Performance Requirements

6.5.3 Information on the As-Built Geometry, Materials andReinforcement

6.5.4 Seismic Analysis and Models

6.5.5 Estimation of Force Demands by Capacity Design In Lieu of Linear Analysis

6.5.6 Verification Criteria for Existing, Retrofitted, orNewMembers

6.5.7 Masonry Infills in Assessment and Retrofitting

6.5.8 Force-Based Assessment and Retrofitting (the “q-factor Approach”)

6.6 Liability Questions in Seismic Assessment and Retrofitting

6.7 Retrofitting Strategies

6.7.1 General Guidelines

6.7.2 Reduction of Seismic Action Effects Through Retrofitting

6.7.3 Upgrading of Member Capacities

6.7.4 Completeness of the Load-Path

6.8 Retrofitting Techniques for Concrete Members

6.8.1 Repair of Damaged Members

6.8.2 Concrete Jacketing

6.8.3 Jackets of Externally Bonded Fibre Reinforced Polymers (FRP)

6.8.4 Steel Jacketing

6.9 Stiffening and Strengthening of the Structure as a Whole

6.9.1 Introduction

6.9.2 Addition of New Concrete Walls

6.9.3 Addition of a New Bracing System in Steel

6.10 ApplicationCaseStudies

6.10.1 Seismic Retrofitting of SPEAR Test-Structure withRCorFRPJackets

6.10.2 Seismic Retrofitting of Theatre Building with RCandFRPJackets andNewWalls