Reinforced Concrete Mechanics and Design 7th Edition by James Wight 0134183371 9780134183374

1 Introduction

1-1 Reinforced Concrete Structures

1-2 Mechanics of Reinforced Concrete

1-3 Reinforced Concrete Members

1-4 Factors Affecting Choice of Reinforced Concrete for a Structure

1-5 Historical Development of Concrete and Reinforced Concrete as Structural Materials

Cement and Concrete

Reinforced Concrete

Design Specifications for Reinforced Concrete

1-6 Building Codes and the ACI Code

References

2 The Design Process

2-1 Objectives of Design

2-2 The Design Process

2-3 Limit States and the Design of Reinforced Concrete

Limit States

Limit-States Design

Basic Design Relationship

2-4 Structural Safety

2-5 Probabilistic Calculation of Safety Factors

2-6 Design Procedures Specified in the ACI Building Code

Strength Design

Plastic Design

Plasticity Theorems

2-7 Load Factors and Load Combinations in the 2014 ACI Code

Terminology and Notation

Load Factors and Load Combinations

Load Combinations

Earthquake Loads

Dead Loads That Stabilize Overturning and Sliding

Load Factor for Small Live Loads

Lateral Earth Pressure

Self-Straining Effects

Strength-Reduction Factors, ϕ

Flexure or Combined Flexure and Axial Load

Other actions

2-8 Loadings and Actions

Direct and Indirect Actions

Classifications of Loads

Loading Specifications

Dead Loads

Live Loads Due to Use and Occupancy

Classification of Buildings for Wind, Snow, and Earthquake Loads

Snow Loads, S

Roof Live Loads, Lr, and Rain Loads, R

Construction Loads

Wind Loads

Earthquake Loads

Self-Equilibrating Loadings

Other Loads

2-9 Design for Economy

2-10 Sustainability

2-11 Customary Dimensions and Construction Tolerances

2-12 Inspection

2-13 Accuracy of Calculations

2-14 Handbooks and Design AIDS

References

3 Materials

3-1 Concrete

3-2 Behavior of Concrete Failing in Compression

Mechanism of Failure in Concrete Loaded in Compression

3-3 Compressive Strength of Concrete

Core Tests

Strength of Concrete in a Structure

3-4 Strength Under Tensile and Multiaxial Loads

Tensile Strength of Concrete

Standard Tension Tests

Relationship between Compressive and Tensile Strengths of Concrete

Factors Affecting the Tensile Strength of Concrete

Strength under Biaxial and Triaxial Loadings

Biaxial Loading of Uncracked, Unreinforced Concrete

Compressive Strength of Cracked Reinforced Concrete

Triaxial Loadings

3-5 Stress–Strain Curves for Concrete

Tangent and Secant Moduli of Elasticity

Stress–Strain Curve for Normal-Weight Concrete in Compression

Equations for Compressive Stress–Strain Diagrams

Stress–Strain Curve for Normal-Weight Concrete in Tension

Poisson’s Ratio

3-6 Time-Dependent Volume Changes

Shrinkage

Creep of Unrestrained Concrete

Restrained Creep

Thermal Expansion

3-7 High-Strength Concrete

High-Performance Concrete

Mechanical Properties

28-Day and 56-Day Compression Strengths

Shrinkage and Creep

3-8 Lightweight Concrete

3-9 Fiber Reinforced Concrete

3-10 Durability of Concrete

3-11 Behavior of Concrete Exposed to High and Low Temperatures

High Temperatures and Fire

Very Cold Temperatures

3-12 Shotcrete

3-13 High-Alumina Cement

3-14 Reinforcement

Hot-Rolled Deformed Bars

Grades, Types, and Sizes

Mechanical Properties

Fatigue Strength

Strength at High Temperatures

Welded-Wire Reinforcement

3-15 Fiber-Reinforced Polymer (FRP) Reinforcement

Properties of FRP Reinforcement

3-16 Prestressing Steel

Problems

References

4 Flexure: Behavior and Nominal Strength of Beam Sections

4-1 Introduction

Analysis versus Design

Required Strength and Design Strength

Positive and Negative Moments

Symbols and Notation

4-2 Flexure Theory

Statics of Beam Action

Flexure Theory for Reinforced Concrete

Basic Assumptions in Flexure Theory

Flexural Behavior

Cracking Point

Yield Point

Points beyond the Yield Point

Effect of Major Section Variables on Strength and Ductility

4-3 Simplifications in Flexure Theory for Design

Whitney Stress Block

4-4 Analysis of Nominal Moment Strength for Singly Reinforced Beam Sections

Stress and Strain Compatibility and Section Equilibrium

Analysis of Nominal Moment Strength, Mn

4-5 Definition of Balanced Conditions

4-6 Code Definitions of Tension-Controlled and Compression-Controlled Sections

Definitions of Effective Depth and Distance to Extreme Layer of Tension Reinforcement

Definitions of Tension-Controlled and Compression-Controlled Sections

Upper Limit on Beam Reinforcement

4-7 Beams with Compression Reinforcement

Effect of Compression Reinforcement on Strength and Behavior

Reasons for Providing Compression Reinforcement

Analysis of Nominal Moment Strength, Mn

Analysis of Strength-Reduction Factor, ϕ

Minimum Tension Reinforcement and Ties for Compression Reinforcement

4-8 Analysis of Flanged Sections

Effective Flange Width and Reinforcement in the Transverse Direction

Analysis of Nominal Moment Strength for Flanged Sections in Positive Bending

Determination of Strength-Reduction Factor, ϕ

Evaluation of As,min in Flanged Sections

4-9 Unsymmetrical Beam Sections

Problems

References

5 Flexural Design of Beam Sections

5-1 Introduction

5-2 Analysis of Continuous One-Way Floor Systems

Load Paths in a One-Way Floor System

Tributary Areas, Pattern Loadings, and Live Load Reductions

Pattern Loadings for Live Load

Live Load Reductions

ACI Moment and Shear Coefficients

Typical Factored Load Combinations for a Continuous Floor System

Structural Analysis of Continuous Beams and One-Way Slabs

5-3 Design of Singly Reinforced Beam Sections with Rectangular Compression Zones

General Factors Affecting the Design of Rectangular Beams

Location of Reinforcement

Construction of Reinforced Concrete Beams and Slabs

Preliminary Beam and Slab Depths for Control of Deflections

Concrete Cover and Bar Spacing

Calculation of Effective Depth and Minimum Web Width for a Given Bar Arrangement

Estimating the Effective Depth of a Beam and One-Way Slab

Minimum Reinforcement

General Strength Design Requirements for Beams

Design of Tension Reinforcement When Section Dimensions Are Known

Design of Beams When Section Dimensions Are Not Known

5-4 Design of Doubly Reinforced Beam Sections

5-5 Design of Continuous One-Way Slabs

Problems

References

6 Shear in Beams

6-1 Introduction

6-2 Basic Theory

Stresses in an Uncracked Elastic Beam

Average Shear Stress between Cracks

Beam Action and Arch Action

Shear Reinforcement

6-3 Behavior of Beams Failing in Shear

Behavior of Beams without Web Reinforcement

Inclined Cracking

Internal Forces in a Beam without Stirrups

Factors Affecting the Shear Strength of Beams without Web Reinforcement

Behavior of Beams with Web Reinforcement

Behavior of Beams Constructed with Fiber Reinforced Concrete

6-4 Analysis and Design of Reinforced Concrete Beams for Shear—ACI Code

Shear-Failure Limit States: Beams without Web Reinforcement

Design Equations for the Shear Strength of Members without Web Reinforcement

Axial Compression

Axial Tension

Circular Cross Sections.

Shear Failure Limit States: Beams with Web Reinforcement

Types of Web Reinforcement

Minimum Web Reinforcement

Strength-Reduction Factor for Shear

Location of Maximum Shear for the Design of Beams

Shear at Midspan of Uniformly Loaded Beams

High-Strength Concrete

6-5 Other Shear Design Methods

Definitions and Design Methods

Traditional ACI Design Procedure

Compression Field Theories

Shear Friction Method

Equivalence of Shears on Inclined and Vertical Planes

6-6 Hanger Reinforcement

6-7 Tapered Beams

6-8 Shear in Axially Loaded Members

Axial Tension

Axial Compression

Problems

References

7 Torsion

7-1 Introduction and Basic Theory

Shearing Stresses due to Torsion in Uncracked Members

Solid Members

Hollow Members

Principal Stresses due to Torsion

Stresses due to Torsion, Shear and Moment

Circulatory Torsion and Warping Torsion

7-2 Behavior of Reinforced Concrete Members Subjected to Torsion

Prior to Cracking

After Cracking

7-3 Thin-Walled Tube Analogies

7-4 Design for Torsion and Shear—ACI Code Approach

Area of Longitudinal Reinforcement

Value of θ

Limits on Concrete and Steel Strengths for Design

Combined Shear and Torsion

Amounts of Torsional and Shear Reinforcement

Types of Torsional Reinforcement and Its Anchorage

Minimum Torsional Reinforcement

Spacing of Torsional Reinforcement

Maximum Shear and Torsion

Crack Width Limit

Web Crushing Limit

Combined Moment and Torsion

7-5 ACI Code Design Method for Torsion

Problems

References

8 Development, Anchorage, and Splicing of Reinforcement

8-1 Introduction

Average Bond Stress in a Beam

Bond Stresses in an Axially Loaded Prism

True Bond Stresses in a Beam

Bond Stresses in a Pull-Out Test

8-2 Mechanism of Bond Transfer

8-3 Development Length

Tension-Development Lengths

Analysis of Bond Splitting Load

Basic Tension-Development Equation

Simplified Tension-Development-Length Equations

Bar-Spacing Factor, cb

Factors in Eqs. (8-10) through (8-14)

Excess Flexural Reinforcement

Compression-Development Lengths

Development Lengths for Bundled Bars

Development Lengths for Coated Bars

Development Lengths for Welded-Wire Reinforcement

8-4 Hooked Anchorages

Behavior of Hooked Anchorages

Development of Hooked Bars in Tension

Values for λ and ψ-factors, ACI Code Table 25.4.3.2

8-5 Headed and Mechanically Anchored Bars in Tension

8-6 Design for Anchorage

8-7 Bar Cutoffs and Development of Bars in Flexural Members

Why Bars Are Cutoff

Location of Flexural Cutoff Points

Effect of Shear on Bar Forces and Location of Bar Cutoff Points

Development of Bars at Points of Maximum Bar Force

Development of Bars in Positive-Moment Regions

Effect of Discontinuities at Bar Cutoff Points in Flexural Tension Zones

8-8 Reinforcement Continuity and Structural Integrity Requirements

Continuity Reinforcement

Structural-Integrity Reinforcement

Graphical Calculation of Flexural Cutoff Points

Standard Cutoff Points

8-9 Splices

Tension Lap Splices

Compression Lap Splices

Welded, Mechanical, and Butt Splices

Problems

References

9 Serviceability

9-1 Introduction

Serviceability Limit States

9-2 Elastic Analysis of Stresses in Beam Sections

Calculation of EI

Modulus of Elasticity and Modular Ratio

Transformed Section

Uncracked Transformed Section

Cracked Transformed Section

Service-Load Stresses in a Cracked Beam

Cracked-Transformed Section Analysis for Flanged Sections

9-3 Cracking

Types of Cracks

Development of Cracks due to Loads

Reasons for Controlling Crack Widths

Limits on Crack Width

Shrinkage and Temperature Reinforcement

Web Face Reinforcement

9-4 Deflections of Concrete Beams

Load–Deflection Behavior of a Concrete Beam

Flexural Stiffness and Moment of Inertia

Effective Moment of Inertia

Instantaneous and Additional Sustained Load Deflections

Instantaneous Deflections

Sustained-Load Deflections

9-5 Consideration of Deflections in Design

Serviceability Limit States Resulting from Flexural Deflections

Visual Appearance

Damage to Nonstructural Elements

Disruption of Function

Damage to Structural Elements

Allowable Deflections

Accuracy of Deflection Calculations

Deflection Control by Span-to-Depth Limits

9-6 Frame Deflections

Lateral Deflections

Member Stiffnesses

Vertical Deflections

9-7 Vibrations

9-8 Fatigue

Problems

References

10 Continuous Beams and One-Way Slabs

10-1 Introduction

10-2 Continuity in Reinforced Concrete Structures

Braced and Unbraced Frames

Design Loads for a Continuous Floor System

Transfer of Column Loads through the Floor System

10-3 Continuous Beams

10-4 Design of Girders

10-5 Joist Floors

Standard Dimensions and Layout of One-Way Joists

Reinforcing Details

10-6 Moment Redistribution

Problems

References

11 Columns: Combined Axial Load and Bending

11-1 Introduction

11-2 Tied and Spiral Columns

Behavior of Tied and Spiral Columns

Strength of Axially Loaded Columns

11-3 Interaction Diagrams

11-4 Interaction Diagrams for Reinforced Concrete Columns

Strain-Compatibility Solution

Concept and Assumptions

Significant Points on the Column Interaction Diagram

Strength-Reduction Factor for Columns

Maximum Axial Load

Derivation of Computation Method for Interaction Diagrams

Concentric Compressive Axial-Load Capacity and Maximum Axial-Load Capacity

General Case

Pure-Axial-Tension Case

Interaction Diagrams for Circular Columns

Properties of Interaction Diagrams for Reinforced Concrete Columns

Nondimensional Interaction Diagrams

Eccentricity of Load

Unsymmetrical Columns

Simplified Interaction Diagrams for Columns

11-5 Design of Short Columns

Types of Calculations—Analysis and Design

Factors Affecting the Choice of Column

Choice of Column Type

Choice of Material Properties and Reinforcement Ratios

Estimating the Column Size

Tied Columns

Spiral Columns

Slender Columns

Bar-Spacing Requirements

Reinforcement Splices

Spacing and Construction Requirements for Ties

Amount of Spirals and Spacing Requirements

11-6 Contributions of Steel and Concrete to Column Strength

11-7 Biaxially Loaded Columns

Problems

References

12 Slender Columns

12-1 Introduction

Definition of a Slender Column

Buckling of Axially Loaded Elastic Columns

Slender Columns in Structures

Organization of Chapter 12

12-2 Behavior and Analysis of Pin-Ended Columns

P−δ Moments and P−Δ Moments

Material Failures and Stability Failures

Slender-Column Interaction Curves

Moment Magnifier for Symmetrically Loaded Pin-Ended Beam Column

Effect of Unequal End Moments on the Strength of a Slender Column

Column Rigidity, EI

Design Values of (EI)eff for the Computation of the Critical Loads of Individual Columns

EI for the Computation of Frame Deflections and for Second-Order Analyses

Effect of Sustained Loads on Pin-Ended Columns

Effect of Loading History

Creep Buckling

Limiting Slenderness Ratios for Slender Columns

Definition of Nonsway and Sway Frames

Including Slenderness Effects

Summary of ACI Moment Magnifier Design Procedure for Columns in Nonsway Frames

12-3 Design of Columns in Nonsway Frames

Design Approximation for the Effect of End Restraints in Nonsway Frames

Calculation of k from Tables

Calculation of k via Nomographs

Calculation of ψ, Column-Beam Frames

Calculation of ψ, Column Footing Joints

12-4 Behavior of Restrained Columns in Sway Frames

Statics of Sway Frames

Mns and Ms Moments

12-5 Calculation of Moments in Sway Frames Using Second-Order Analysis

First-Order and Second-Order Analysis

Second-Order Analysis

Load Level for the Analysis

Lateral Stiffness-Reduction Factor

Stiffnesses of the Members

Foundation Rotations

Effect of Sustained Loads

Methods of Second-Order Analysis

Iterative P−Δ Analysis

Direct P−Δ Analysis for Sway Frames

12-6 Design of Columns in Sway Frames

Overview

Computation of δsMs

1. Computation of δsMs Using Second-Order Analyses

2. Computation of δsMs Using Direct P−Δ Analysis

3. Computation of δsMs Using Sway-Frame Moment Magnifier

Moments at the Ends of the Columns

Maximum Moment between the Ends of the Column

Sidesway Buckling under Gravity Loads

Minimum Moment

Load Case 2: Gravity plus Lateral (Wind) Loads

12-7 General Analysis of Slenderness Effects

12-8 Torsional Critical Load

Problems

References

13 Two-Way Slabs: Behavior, Analysis, and Design

13-1 Introduction

13-2 History of Two-Way Slabs

13-3 Behavior of Slabs Loaded to Failure in Flexure

13-4 Analysis of Moments in Two-Way Slabs

Nichols’ Analysis of Moments in Slabs

13-5 Distribution of Moments in Slabs

Relationship between Slab Curvatures and Moments

Moments in Slabs Supported by Stiff Beams or Walls

Moments in Slabs Supported by Isolated Columns

13-6 Design of Slabs

Steps in Slab Design

Beam-to-Slab Stiffness Ratio, αf

Minimum Thickness of Two-Way Slabs

Slabs without Beams between Interior Columns

Slabs with Beams between the Interior Supports

13-7 The Direct-Design Method

Limitations on the Use of the Direct-Design Method

Distribution of Moments within Panels—Slabs without Beams between All Supports

Statical Moment, Mo

Positive and Negative Moments in Panels

Provision for Pattern Loadings

Provision for Concentrated Loads

Definition of Column Strips and Middle Strips

Distribution of Moments between Column Strips and Middle Strips

Transfer of Moments to Columns

Exterior Columns

Interior Columns

13-8 Equivalent-Frame Methods

Classic Equivalent-Frame Analysis of Slab Systems for Vertical Loads

Calculation of Stiffness, Carryover, and Fixed-End Moments

Properties of Slab-Beams

Properties of Columns

Torsional Members and Equivalent Columns

Arrangement of Live Loads for Structural Analysis

Moments at the Face of Supports

Distribution of Moments to Column Strips, Middle Strips, and Beams

13-9 Use of Computers for an Equivalent-Frame Analysis

Analysis of Slab–Column Frames for Combined Gravity and Lateral Loads

13-10 Shear Strength of Two-Way Slabs

Behavior of Slabs Failing in Two-Way Shear—Interior Columns

Design for Two-Way Shear

Location of the Critical Perimeter

Critical Sections for Slabs with Drop Panels

Critical Sections Near Holes and at Edges

Tributary Areas for Shear in Two-Way Slabs

Design Equations for Two-Way Shear

Punching Shear, vc, Carried by Concrete in Two-Way Slabs

One-Way Shear in Slabs

Augmenting the Shear Strength

Shear Reinforcement for Two-Way Slabs

Stirrups

Structural Steel Shearheads

Headed Shear Studs

Design of Shear Reinforcement

13-11 Combined Shear and Moment Transfer in Two-Way Slabs

Slab–Column Connections Loaded with Shear and Moment

Properties of Critical Shear Perimeters

Polar Moment of Inertia, Jc, for an Isolated Side of a Critical Shear Perimeter

Section Properties of a Closed Rectangular Critical Shear Section

Edge Columns

Corner Columns

Circular Columns

Load Patterns for Maximum Shear Stress due to Combined Shear and Moment Transfer

Calculation of Moment about Centroid of Shear Perimeter

Consideration of Moment Transfer in Both Principal Directions

Alternative Analysis of Maximum Shear Stress due to Combined Shear and Moment Transfer at Exterior Connections

Shear Reinforcement for Slab–Column Connections Transferring Shear and Moment

13-12 Details and Reinforcement Requirements

Drop Panels

Column Capitals

Shear Caps

Reinforcement

Placement Sequence

Cover and Effective Depth

Spacing Requirements, Minimum Reinforcement, and Minimum Bar Size

Calculation of the Required Area of Steel

Bar Cutoffs and Anchorages

Detailing Slab Reinforcement at an Edge Column

Structural Integrity Reinforcement

13-13 Design of Slabs Without Beams

13-14 Design of Slabs with Beams in Two Directions

13-15 Construction Loads on Slabs

13-16 Deflections in Two-Way Slab Systems

13-17 Use of Post-Tensioning

Problems

References

14 Two-Way Slabs: Elastic and Yield-Line Analyses

14-1 Review of Elastic Analysis of Slabs

14-2 Design Moments from a Finite-Element Analysis

14-3 Yield-Line Analysis of Slabs: Introduction

Yield Criterion

Locations of Axes and Yield Lines

Methods of Solution

Virtual-Work Method

14-4 Yield-Line Analysis: Applications For Two-Way Slab Panels

14-5 Yield-Line Patterns at Discontinuous Corners

14-6 Yield-Line Patterns at Columns or at Concentrated Loads

Problems

References

15 Footings

15-1 Introduction

15-2 Soil Pressure Under Footings

Design Methods

Allowable Stress Design

Limit-States Design

Limit States for the Design of Foundations

Limit States Governed by the Soil

Limit States Governed by the Structure

Elastic Distribution of Soil Pressure under a Footing

Elastic and Plastic Soil-Pressure Distributions

Load and Resistance Factors for Footing Design

Gross and Net Soil Pressures

Factored Net Soil Pressure, qnu.

15-3 Structural Action of Strip and Spread Footings

Flexure

Development of Reinforcement

Shear

One-Way Shear

Two-Way Shear

Transfer of Load from Column to Footing

Bearing Strength

No Moment Transferred to Footing

Moments Are Transferred to Footing

Practical Aspects

15-4 Strip or Wall Footings

15-5 Spread Footings

Rectangular Footings

Footings Transferring Vertical Load and Moment

15-6 Combined Footings

15-7 Mat Foundations

15-8 Pile Caps

Problems

References

16 Shear Friction, Horizontal Shear Transfer, and Composite Concrete Beams

16-1 Introduction

16-2 Shear Friction

Behavior in Shear-Friction Tests

Cohesion and Friction

Shear-Friction Model

Permanent Compression Force

Inclined Shear-Friction Reinforcement

Other Factors Affecting Shear Transfer

Lightweight Concrete

Coefficients of Friction

Design Rules in the ACI Code

Upper Limit on Shear Friction

Cohesion-Plus-Friction Model

Walraven Model

Loov and Patnaik—Composite Beams

Comparison of Design Rules with Test Results

16-3 Composite Concrete Beams

Shored or Unshored Construction

Horizontal Shear

Computation of Horizontal Shear Stress

Calculation of Horizontal Shear Stresses from C and T Forces

Deflections

References

17 Discontinuity Regions and Strut-and-Tie Models

17-1 Introduction

Definition of Discontinuity Regions

Saint Venant’s Principle and Extent of D-Regions

Behavior of D-Regions

Strut-and-Tie Models

17-2 Struts

Strut Failure by Longitudinal Cracking

Compression Failure of Strut

Explanation of Types of Struts Described in Table 17-1

17-3 Ties

17-4 Nodes and Nodal Zones

Hydrostatic Nodal Zones

Geometry of Hydrostatic Nodal Zones

Extended Nodal Zones

Strength of Nodal Zones

Subdivision of Nodal Zones

Resolution of Forces Acting on a Nodal Zone

Anchorage of Ties in Nodal Zones

Nodal Zone Anchored by a Bent Bar

Strut Anchored by Reinforcement

17-5 Other Strut-and-Tie Elements

Compression Fans

Compression Fields

Force Whirls, U-Turns

17-6 Layout of Strut-and-Tie Models

Factors Affecting the Choice of Strut-and-Tie Models

Equilibrium

Direction of Struts and Ties

Suitable Strut-and-Tie Layouts

17-7 Deep Beams

Definition of Deep Beam

Analyses and Behavior of Deep Beams

Design Using Strut-and-Tie Models

17-8 Continuous Deep Beams

Reactions of Continuous Deep Beams

17-9 Brackets and Corbels

Structural Action

Design of Corbels

Alternate Design Method for Corbels

Comparison of the Strut-and-Tie Method and the Traditional ACI Method for Corbel Design

17-10 Dapped Ends

17-11 Beam–Column Joints

Corner Joints: Opening

Corner Joints: Closing

T Joints

Beam–Column Joints in Frames

Classification of Joints

Calculation of Shear Forces in Joints

Shear Strength of Type-1 Joints (Nonseismic)

Shear Strength of Type-2 Joints (Seismic)

Joints between Wide Beams and Narrow Columns

Use of Strut-and-Tie Models in Joint Design

17-12 Bearing Strength

Internal Forces near Bearing Areas

ACI Code Requirements for Bearing Areas

17-13 T-Beam Flanges

Problems

References

18 Walls and Shear Walls

18-1 Introduction

Definitions—Walls and Wall Loadings

Types of Walls

One-Way and Two-Way Walls

Wall Assemblies

Notation

18-2 Bearing Walls

18-3 Retaining Walls

18-4 Tilt-Up Walls

18-5 Shear Walls

18-6 Lateral Load-Resisting Systems for Buildings

18-7 Shear-Wall–Frame Interaction

Bounds on the Forces in a Shear-Wall–Frame Building

18-8 Coupled Shear Walls

Statical System

Analysis of Coupled Walls

18-9 Design of Structural Walls—General

Layout of Building

Diaphragms

Distribution of Walls in a Building Floor Plan

Distribution of Story Forces (Story Shears) to Walls

Wall Foundations

Required Size of Wall

Limits on Story Drift

Minimum Wall Thickness

Reinforcement in Shear Walls

Distributed and Concentrated Reinforcement

Minimum Wall Reinforcement

Ties for Vertical Reinforcement

Transfer of Wall Load through Floor Systems

18-10 Flexural Strength of Shear Walls

Flexure—Nominal Strength, Factored Loads, and Resistance Factors

Strength-Reduction Factors for Flexure and Axial Load

Tension-Controlled Limit for a Rectangular Wall.

Compression-Controlled Limit for a Rectangular Wall.

Flexural Strength of Rectangular Walls with Uniform Curtains of Vertical Distributed Reinforcement

Moment Resistance of Wall Assemblies, Walls with Flanges, and Walls with Boundary Elements

Nominal Moment Strength of Walls with Boundary Elements or Flanges

Nominal Moment Strength of Wall Assemblies

Shear Transfer between Wall Segments in Wall Assemblies

18-11 Shear Strength of Shear Walls

Vc for Shear Walls

Shear Reinforcement for Structural Walls

Shear Strength of Structural Walls Resisting Seismic Loads

Shear Transfer across Construction Joints

18-12 Critical Loads for Axially Loaded Walls

Buckling of Compressed Walls

Buckling of Compressed Walls

Properties of Concrete Affecting the Stability of Concrete Walls

Compressive Stress–Strain Curve for the Concrete

Post Buckling Behavior of Concrete Plates

Stability of Compressed Flanges.

Problems

References

19 Design for Earthquake Resistance

19-1 Introduction

Definitions

Seismic Design Requirements

19-2 Seismic Response Spectra

Velocity and Displacement Spectra

Factors Affecting Peak Response Spectra

Period of Building

Effect of Damping on Response Spectrum

Effect of Ductility on Seismic Forces

Effect of Foundation Soil Stiffness on Response Spectrum

19-3 Seismic Design Requirements

Seismic Design Categories

Lateral Force-Resisting Structural Systems

Effect of Building Configuration

Plan Irregularities

Vertical Irregularities

19-4 Seismic Forces on Structures

Equivalent Lateral Force Method for Computing Earthquake Forces

Seismic Base Shear, V

Seismic Response Coefficient, CS

Effective Seismic Weight of the Building, W

Response-Modification Factor, R

Distribution of Lateral Forces over the Height of a Building

Story Shear

Story Torsion

Analysis

19-5 Ductility of Reinforced Concrete Members

19-6 General ACI Code Provisions for Seismic Design

Applicability

Materials

Load Factors, Load Combinations, and Strength-Reduction Factors

Load and Resistance Factors—ACI Code

Capacity Design

Strong-Column–Weak-Beam Design

19-7 Beams in Special Moment Frames

Geometric Limits on Beam Cross Sections

Classification of Moment Strengths

Computation of Moment Strength of Beam Sections

Longitudinal Reinforcement

Development and Splicing of Flexural Reinforcement

Transverse Reinforcement

Confinement Reinforcement

Shear Reinforcement

19-8 Columns in Special Moment Frames

Required Capacity and Longitudinal Reinforcement

Transverse Reinforcement

Confinement Reinforcement

Shear Reinforcement

19-9 Joints of Special Moment Frames

19-10 Structural Diaphragms

Flexural Strength

Shear Strength

Effect of Diaphragm Stiffness on Lateral-Load Distribution

19-11 Structural Walls

Design of Shear Walls

Design for Shear

Strength-Reduction Factor

Coupled Walls and Coupling Beams

Wall Foundations

19-12 Frame Members not Proportioned to Resist Forces Induced by Earthquake Motions

19-13 Special Precast Structures

19-14 Foundations

Problems

References

Appendix A Design Aids

Tables

Figures

Appendix B Notation