2012 ibc outline

2012 IBC®

SEAOC STRUCTURAL/SEISMIC DESIGN MANUAL

Volume 1CODE APPLICATION EXAMPLES

ii 2012 IBC SEAOC Structural/Seismic Design Manual, Vol. 1

Copyright

Copyright © 2013 Structural Engineers Association of California. All rights reserved. This publication or any part thereof must not be reproduced in any form without the written permission of the Structural Engineers Association of California.

Publisher

Structural Engineers Association of California (SEAOC)1400 K Street, Ste. 212Sacramento, California 95814Telephone: (916) 447-1198; Fax: (916) 444-1501E-mail: [email protected]; Web address: www.seaoc.org

The Structural Engineers Association of California (SEAOC) is a professional association of four regional member organizations (Southern California, Northern California, San Diego, and Central California). SEAOC represents the structural engineering community in California. This document is published in keeping with SEAOC’s stated mission:

To advance the structural engineering profession; to provide the public with structures of dependable performance through the application of state-of-the-art structural engineering principles; to assist the public in obtaining professional structural engineering services; to promote natural hazard mitigation; to provide continuing education and encourage research; to provide structural engineers with the most current information and tools to improve their practice; and to maintain the honor and dignity of the profession.

SEAOC Board oversight of this publication was provided by 2012 SEAOC Board President James Amundson, S.E. and Immediate Past President Doug Hohbach, S.E.

Editor

International Code Council

Disclaimer

While the information presented in this document is believed to be correct, neither SEAOC nor its member organizations, committees, writers, editors, or individuals who have contributed to this publication make any warranty, expressed or implied, or assume any legal liability or responsibility for the use, application of, and/or reference to opinions, findings, conclusions, or recommendations included in this publication. The material presented in this publication should not be used for any specific application without competent examination and verification of its accuracy, suitability, and applicability. Users of information from this publication assume all liability arising from such use.

First Printing: September 2013

00_FM 2012 IBC SSDM V1.indd 2 9/6/2013 1:11:36 PM

2012 IBC SEAOC Structural/Seismic Design Manual, Vol. 1 iii

Suggestions for Improvement

Comments and suggestions for improvements are welcome and should be sent to the following:

Structural Engineers Association of California (SEAOC)Don Schinske, Executive Director1400 K Street, Suite 212Sacramento, California 95814Telephone: (916) 447-1198; Fax: (916) 444-1501E-mail: [email protected]

Errata Notification

SEAOC has made a substantial effort to ensure that the information in this document is accurate. In the event that corrections or clarifications are needed, these will be posted on the SEAOC Web site at www.seaoc.org and on the ICC Web site at www.iccsafe.org.

SEAOC, at its sole discretion, may issue written errata.


2012 IBC SEAOC Structural/Seismic Design Manual, Vol. 1 v

Table of Contents

Preface to the 2012 IBC SEAOC Structural/Seismic Design Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . xi

Preface to Volume 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii

Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii

How to Use This Document. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xix

Design Example 1

Design Spectral Response Acceleration Parameters . . . . . . . . . . . . . . . . . . . . . . . .§11.4 . . . . . . . .1

Design Example 2

Design Response Spectrum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . §11.4.5 . . . . . . . .3

Design Example 3

Site-Specific Ground Motion Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . §11.4.7 . . . . . . . .6

Design Example 4

Importance Factor and Risk Category . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .§11.5 Seismic Design Category . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .§11.6 . . . . . . .11

Design Example 5

Continuous Load Path and Interconnection . . . . . . . . . . . . . . . . . . . . . . . . . . . . §12.1.3 Connection to Supports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . §12.1.4 . . . . . . .13

Design Example 6

Combination of Framing Systems in Different Directions . . . . . . . . . . . . . . . . . §12.2.2 . . . . . . .15

Design Example 7

Combination of Framing Systems in The Same Direction: Vertical . . . . . . . .§12.2.3.1 . . . . . . .17

Design Example 8

Combination of Framing Systems in The Same Direction: Horizontal . . . . . .§12.2.3.3 . . . . . . .23

Design Example 9

Combination Framing Detailing Requirements . . . . . . . . . . . . . . . . . . . . . . . . . §12.2.4 . . . . . . .25


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Design Example 10

Dual Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .§12.2.5.1 . . . . . . .28

Design Example 11

Introduction to Horizontal Irregularities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .§12.3.2.1 . . . . . . .31

Design Example 12

Horizontal Irregularity Type 1a and Type 1b . . . . . . . . . . . . . . . . . . . . . . . . . .§12.3.2.1 . . . . . . .32

Design Example 13

Horizontal Irregularity Type 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .§12.3.2.1 . . . . . . .36

Design Example 14


Design Example 15


Design Example 16


Design Example 17

Introduction to Vertical Irregularities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .§12.3.2.2 . . . . . . .43

Design Example 18

Vertical Irregularity Type 1a and Type 1b . . . . . . . . . . . . . . . . . . . . . . . . . . . .§12.3.2.2 . . . . . . .44

Design Example 19

Vertical Irregularity Type 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .§12.3.2.2 . . . . . . .48

Design Example 20


Design Example 21


Design Example 22

Vertical Irregularity Type 5a/5b – Concrete Wall . . . . . . . . . . . . . . . . . . . . . . .§12.3.2.2 . . . . . . .54


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Design Example 23

Vertical Irregularity Type 5a/5b – Steel Moment Frame . . . . . . . . . . . . . . . . .§12.3.2.2 . . . . . . .56

Design Example 24

Elements Supporting Discontinuous Walls or Frames . . . . . . . . . . . . . . . . . . .§12.3.3.3 . . . . . . .60

Design Example 25

Elements Supporting Discontinuous Walls or Frames – Light-Frame . . . . . . .§12.3.3.3 . . . . . . .64

Design Example 26

Redundancy Factor r . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . §12.3.4 . . . . . . .67

Design Example 27

Seismic Load Combinations: Strength Design . . . . . . . . . . . . . . . . . . . . . . . . .§12.4.2.3 . . . . . . .72

Design Example 28

Minimum Upward Force for Horizontal Cantilevers for SDC D through F . . . §12.4.4 . . . . . . .75

Design Example 29

Interaction Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . §12.7.4 . . . . . . .78

Design Example 30

Seismic Base Shear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . §12.8.1 . . . . . . .80

Design Example 31

Approximate Fundamental Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .§12.8.2.1 . . . . . . .83

Design Example 32

Vertical Distribution of Seismic Forces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . §12.8.3 . . . . . . .87

Design Example 33

Horizontal Distribution of Forces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . §12.8.4 . . . . . . .91

Design Example 34

Amplification of Accidental Torsion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .§12.8.4.3 . . . . . . .96

Design Example 35

Story Drift . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . §12.8.6 . . . . . .100


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Design Example 36

P-delta Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . §12.8.7 . . . . . .103

Design Example 37

Scaling Design Values of Combined Response . . . . . . . . . . . . . . . . . . . . . . . . . §12.9.4 . . . . . .108

Design Example 38

Diaphragm Design Forces, Fpx: Lowrise . . . . . . . . . . . . . . . . . . . . . . . . . . . §12.10.1.1 . . . . . .112

Design Example 39

Diaphragm Design Forces, Fpx: Highrise . . . . . . . . . . . . . . . . . . . . . . . . . . . .§12.10.1.1 . . . . . .116

Design Example 40

Collector Elements – Flexible Diaphragm . . . . . . . . . . . . . . . . . . . . . . . . . . . . §12.10.2 . . . . . .119

Design Example 41

Out-of-Plane Seismic Forces – One-Story Structural Wall . . . . . . . . §12.11 and §13.3 . . . . . .123

Design Example 42

Out-of-Plane Seismic Forces – Two-Story Structural Wall . . . . . . . §12.11.1 and §12.11.2 . . . . . .127

Design Example 43

Wall Anchorage to Flexible Diaphragms . . . . . . . . . . . . . . . . . . . . . . . . . . . .§12.11.2.1 . . . . . .131

Design Example 44

Story Drift Limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . §12.12.1 . . . . . .134

Design Example 45

Structural Separation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . §12.12.3 . . . . . .137

Design Example 46

Deformation Compatibility for Seismic Design Categories D through F . . . . §12.12.5 . . . . . .140

Design Example 47

Reduction of Foundation Overturning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . §12.13.4 . . . . . .143

Design Example 48

Foundation Ties . . . . . . . . . . . . . . . . . . . . §12.13.5.2, §12.13.6.2, and IBC §1810.3.13 . . . . . .147


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Design Example 49

Simplified Alternative Structural Design Procedure . . . . . . . . . . . . . . . . . . . . . . .§12.14 . . . . . .151

Design Example 50

Seismic Demands on Nonstructural Components on Rigid Supports . . . §13.3 and §13.4 . . . . . .154

Design Example 51

Seismic Demands on Vibration-Isolated Nonstructural Components . . . . §13.3 and §13.4 . . . . . .158

Design Example 52

Seismic Relative Displacements of Component Attachments . . . . . . . . . . . . . . §13.3.2 . . . . . .161

Design Example 53

Exterior Nonstructural Wall Element . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .§13.5 . . . . . .164

Design Example 54

Exterior Nonstructural Wall Element Connections . . . . . . . . . . . . . . . . . . . . . . . .§13.5 . . . . . .167

Design Example 55

Lateral Seismic Force on Nonbuilding Structure . . . . . . . . . . . . . . . . . . . . . . . . . .§15.4 . . . . . .174

Design Example 56

Flexible Nonbuilding Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . §15.4 and §15.5 . . . . . .178

Design Example 57

Rigid Nonbuilding Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . §15.4.2 . . . . . .181

Design Example 58

Retaining Wall with Seismic Lateral Earth Pressure . . . . . . . . . . . . . . . . . . . . . §15.6.1 . . . . . .183


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Preface to the 2012 IBC SEAOC Structural/Seismic Design Manual

The IBC SEAOC Structural/Seismic Design Manual, throughout its many editions, has served the purpose of illustrating good seismic design and the correct application of building-code provisions. The Manual has bridged the gap between the discursive treatment of topics in the SEAOC Blue Book (Recommended Lateral Force Requirements and Commentary) and real-world decisions that designers face in their practice.

The examples illustrate code-compliant designs engineered to achieve good performance under severe seismic loading. In some cases simply complying with building-code requirements does not ensure good seismic response. This Manual takes the approach of exceeding the minimum code requirements in such cases, with discussion of the reasons for doing so.

Recent editions of the IBC SEAOC Structural/Seismic Design Manual have consisted of updates of previous editions, modified to address changes in the building code and referenced standards. Many of the adopted standards did not change between the 2006 edition of the International Building Code and the 2009 edition. The 2012 edition, which is the one used in this set of manuals, represents an extensive change of adopted standards, with many substantial changes in methodology.

Additionally, this edition has been substantially revised. New examples have been included to address new code provisions and new systems, as well as to address areas in which the codes and standards provide insufficient guidance. Important examples such as the design of base-plate anchorages for steel systems and the design of diaphragms have been added.

This expanded edition comprises five volumes:

• Volume 1: Code Application Examples• Volume 2: Examples for Light-Frame, Tilt-Up, and Masonry Buildings• Volume 3: Examples for Reinforced Concrete Buildings• Volume 4: Examples for Steel-Framed Buildings• Volume 5: Examples for Seismically Isolated Buildings and Buildings with Supplemental Damping

Previous editions have been three volumes. This expanded edition contains more types of systems for concrete buildings and steel buildings. These are no longer contained in the same volume. Volumes 3 and 4 of the 2012 edition replace Volume 3 of the 2009 edition. Additionally, we have fulfilled the long-standing goal of including examples addressing seismic isolation and supplemental damping. These examples are presented in the new Volume 5.

In general, the provisions for developing the design base shear, distributing the base-shear-forces vertically and horizontally, checking for irregularities, etc., are illustrated in Volume 1. The other volumes contain more extensive design examples that address the requirements of the material standards (for example, ACI 318 and AISC 341) that are adopted by the IBC. Building design examples do not illustrate many of the items addressed in Volume 1 in order to permit the inclusion of less-redundant content.

Each volume has been produced by a small group of authors under the direction of a manager. The managers have assembled reviewers to ensure coordination with other SEAOC work and publications, most notably the Blue Book, as well as numerical accuracy.

This manual can serve as valuable tool for engineers seeking to design buildings for good seismic response.

Rafael SabelliProject Manager


2012 IBC SEAOC Structural/Seismic Design Manual, Vol. 1 xiii

Preface to Volume 1

Volume 1 of the 2012 IBC SEAOC Structural/Seismic Design Manual addresses the application and interpretation of the seismic provisions of the 2012 International Building Code. More specifically, Chapter 16 of the 2012 IBC requires compliance with the provisions of ASCE/SEI 7-10 “Minimum Design Loads for Buildings and Other Structures," except for Chapter 14 of ASCE 7.

ASCE 7 generally prescribes the loading and methodology to be used in the analysis of a structure or an element. In order to determine strength to resist to the load demands from ASCE 7, the IBC adopts national material design standards (such as ACI, AISC, MSJC, and NDS) to be used for the design of an element of a particular material. The Volume 1 examples focus on the application of the provisions of ASCE 7, while the examples in Volumes 2, 3, and 4 focus more on the application of the material design standards. The Manual is not intended to serve as a building code or to be an exhaustive catalogue of all valid approaches.

Volume 1 presents 58 examples covering most of the key code provisions within ASCE 7 Chapters 11, 12, 13, and 15. Many of the examples are similar to those in previous editions but have been rewritten to more clearly present the material and have been updated to reflect changes to the code provisions and SEAOC recommendations. Additionally, new examples are included in this edition that specifically address provisions related to site-specific ground-motion procedures, combination framing detailing requirements, scaling design values in modal response spectrum analysis, and retaining walls subject to seismic earth pressures.

Whenever possible, the authors have incorporated lessons learned from actual projects into the examples. Readers are welcome to submit other conditions or provisions not addressed in this edition for consideration in future editions.

Ryan A. KerstingVolume Manager


2012 IBC SEAOC Structural/Seismic Design Manual, Vol. 1 xv

Acknowledgements

Volume 1 of the 2012 IBC SEAOC Seismic Design Manual was written and reviewed by a group of highly qualified structural engineers, chosen for their knowledge and experience with structural engineering practice and seismic design. The authors are:

Ryan A. Kersting, S.E., Associate Principal, Buehler & Buehler Structural Engineers — Volume Manager and Author/Reviewer of Various Examples Ryan has over 15 years of experience in the analysis, design, and review of building structures spanning the spectrum of conventional systems and materials. He is also frequently involved in projects that incorporate innovative structural systems, nonlinear analysis, and performance-based designs. Ryan has been very active in SEAOC, including previously serving as Chair of the SEAOC Seismology Committee, co-authoring / reviewing Blue Book articles, and serving as Chair of the 2007 SEAOC Convention. www.bbse.com

April Buchberger, S.E., Senior Structural Engineer, Clark Pacific — Author/Reviewer of Various Examples April has 10 years of experience designing precast concrete structural systems and architectural cladding for the commercial, residential, health care, and government sectors in California. She is active in the SEAOCC (Central California) member organization of SEAOC, where she is currently serving on the Board of Directors and as Website Committee Chair. www.ClarkPacific.com

Timothy S. Lucido, S.E., Associate, Rutherford + Chekene — Author/Reviewer of Various ExamplesTim has 10 years of experience in the seismic design and evaluation of building structures with specialization in hospital design and steel-framed systems. He is a contributing member of SEAOC and SEAONC, including co-authoring the SEAOC Blue Book article “Concentrically Braced Frames.” He has developed proprietary data and software analysis tools for BRB manufacturers, has given webinars on BIM 3D shop drawing review and coordination, and is a BIM leader for Rutherford + Chekene. www.ruthchek.com

Kevin Morton, S.E., Associate Principal, Hohbach-Lewin Structural Engineers — Author/Reviewer of Various Examples Kevin has 12 years of experience designing new structures and retrofitting existing ones, with particular expertise in seismic analysis, value engineering, and precast parking structure design. He is an active member of SEAOC, having served on the state Seismology Committee for the past three years. www.hohbach-lewin.com

Nicolas Rodrigues, PE, SE, Associate, DeSimone Consulting Engineeers — Author/Reviewer of Various Examples Nic has more than 10 years of experience in performing both code-based and performance-based designs of new highrise concrete and steel buildings in seismic zones around the world including California, Turkey, the UAE, and the Philippines. He has chaired several SEAOC committees, served on a PEER committee for the performance-based design of tall buildings, and actively participates in ACI. Nic was the responsible structural engineer for such notable projects as the 60-story Millennium Tower in San Francisco and the twisting, 42-story Emirates Pearl Hotel in Abu Dhabi. www.de-simone.com.


xvi 2012 IBC SEAOC Structural/Seismic Design Manual, Vol. 1

Ali Sumer, Ph.D., S.E., Senior Structural Engineer, State of California Office of Statewide Health Planning and Development (OSHPD) — Author/Reviewer of Various Examples Prior to joining OSHPD, Ali worked in private industry for eight years. He has focused on projects that incorporate seismic retrofitting, innovative structural systems, nonlinear analysis techniques, performance-based designs, building collapse risk analysis, and equipment shake-table tests. www.oshpd.ca.gov

Close collaboration with the SEAOC Seismology Committee was maintained during the development of the document. The Seismology Committee has reviewed the document and provided many helpful comments and suggestions. Their assistance is gratefully acknowledged.

Production and art was provided by the International Code Council.

Cover photo credits: Main photo: Rien van Rijthoven Architecture PhotographyInset photos: Buehler & Buehler Structural Engineers, Inc.


2012 IBC SEAOC Structural/Seismic Design Manual, Vol. 1 xvii

References

Standards

American Concrete Institute. ACI 318: Building Code Regulations for Reinforced Concrete, Farmington Hills, Michigan, 2011.

American Society of Civil Engineers. ASCE 7: Minimum Design Loads for Buildings and Other Structures. ASCE 2010.

International Code Council. International Building Code (IBC). Falls Church, Virginia, 2012.

Other References

SEAOC Seismology Committee. Recommended Lateral Force Requirements and Commentary (Blue Book), Structural Engineers Association of California (SEAOC), Seventh Edition, Sacramento, California, 1999.

SEAOC Seismology Committee. SEAOC Blue Book Seismic Design Recommendations, Structural Engineers Association of California (SEAOC), First Printing, Sacramento, California, 2009. www.seaoc.org/bluebook


2012 IBC SEAOC Structural/Seismic Design Manual, Vol. 1 1

Design Example 1 Design Spectral Response Acceleration Parameters §11.4

OVERVIEW

For a given building site, the risk-targeted maximum considered earthquake spectral response accelerations SS, at short periods, and S1, at a 1-second period, are given by the acceleration contour maps in Chapter 22 in Figures 22-1 through 22-6. This example illustrates the general procedure for determining the design spectral response acceleration parameters SDS and SD1 from the mapped values of SS and S1. The parameters SDS and SD1 are used to calculate the design response spectrum in Section 11.4.5 and the design base shear in Section 12.8.

The easiest and most accurate way to obtain the spectral values is to use the “U.S. Seismic Design Maps” application from the USGS website (http://geohazards.usgs.gov/designmaps/us/application.php). The USGS application allows for values of SS and S1 to be provided based on the address or the longitude and latitude of the site being entered.

PROBLEM STATEMENT

A building site in California is located at 38.123° North (Latitude 38.123°) and 121.123° West (Longitude -121.123°). The soil profile is Site Class D.

DETERMINE THE FOLLOWING:

1. Mapped risk-targeted maximum considered earthquake (MCER) spectral response acceleration parameters SS and S1.

2. Site coefficients Fa and Fv and MCER spectral response acceleration parameters SMS and SM1 adjusted for Site Class effects.

3. Design spectral response acceleration parameters SDS and SD1.

1. Mapped MCER Spectral Response Acceleration Parameters Ss and S1 §11.4.1

For the given site at 38.123° North (Latitude 38.123°) and 121.123° West (Longitude -121.123°), the USGS “U.S. Seismic Design Maps” application provides the values of

SS = 0.634g

S1 = 0.272g.

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2 2012 IBC SEAOC Structural/Seismic Design Manual, Vol. 1

2. Site Coefficients Fa and Fv and MCER Spectral Response Acceleration Parameters SMS and SM1 Adjusted for Site Class Effects §11.4.3

For the given Site Class D and the values of SS and S1 determined above, the site coefficients are

Fa = 1.293 T11.4-1

Fv = 1.856. T11.4-2

The MCER spectral response acceleration parameters adjusted for Site Class effects are

SMS = Fa SS = 1.292(0.634g) = 0.819g Eq 11.4-1

SM1 = Fv S1 = 1.857(0.272g) = 0.505g Eq 11.4-2

3. Design Spectral Response Acceleration Parameters SDS and SD1 §11.4.4

SDS = (2/3) SMS = (2/3)(0.819g) = 0.546g Eq 11.4-3

SD1 = (2/3) SM1 = (2/3)(0.505g) = 0.337g Eq 11.4-4

Commentary

The USGS application “U.S. Seismic Design Maps” requires the risk category to be specified, even though that category is not necessary for determining SDS and SD1.

§11.4 Design Example 1 n Design Spectral Response Acceleration Parameters

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Design Example 2 Design Response Spectrum §11.4.5

PROBLEM STATEMENT

A building site in California has the following design spectral response acceleration parameters determined in accordance with Section 11.4.4 and mapped long-period transition period evaluated from Figure 22-12:

SDS = 0.55g

SD1 = 0.34g

TL = 8 sec.

DETERMINE THE FOLLOWING:

1. Design response spectrum.

1. Design Response Spectrum §11.4.5

Section 11.4.5 provides the equations for the 5 percent damped spectral response acceleration, Sa, relative to period, T, in the following ranges:

0 ≤ T < T0, T0 ≤ T ≤ TS, TS < T ≤ TL, and TL < T

where:

T0 = 0.2 SD1 / SDS,

TS = SD1 / SDS, and

TL = long-period transition period from Figures 22-12 through 22-16.

Given the values above for this example,

T0 = 0.2 SD1 / SDS = 0.2(0.34g / 0.55g) = 0.12 sec

TS = SD1 / SDS = (0.34g / 0.55g) = 0.62 sec, and

TL = 8 sec.

Design Example 2 n Design Response Spectrum §11.4.5

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The spectral response acceleration, Sa, is calculated as follows:

1. For the interval 0 ≤ T < T0 (0 ≤ T < 0.12 s),

Sa = SDS(0.4 + 0.6T/T0) Eq 11.4-5

Sa = 0.55g(0.4+0.6T/0.12) = (0.22 + 2.75T)g.

2. For the interval T0 ≤ T ≤ TS (0.12 s ≤ T ≤ 0.62 s),

Sa = SDS = 0.55g.

3. For the interval TS < T ≤ TL (0.62 s < T ≤ 8 s),

Sa = SD1/T Eq 11.4-6

Sa = (0.34/T)g.

4. For the interval TL < T (8 s < T),

Sa = SD1TL/T2 Eq 11.4-7

Sa = 0.34g(8)/T2 = (2.72/T2)g.

From this information, the elastic design response spectrum for this site can be drawn, as shown below, in accordance with Figure 11.4-1:

T (sec)

Sa (g)

0.00 0.22

0.12 0.55

0.62 0.55

0.75 0.45

1.00 0.34

1.50 0.23

2.00 0.17

4.00 0.09

8.00 0.04

10.00 0.03

§11.4.5 Design Example 2 n Design Response Spectrum

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Figure 2-1. Design response spectrum per Section 11.4.5

Design Example 2 n Design Response Spectrum §11.4.5

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2012 IBC®


Volume 2EXAMPLES FOR LIGHT-FRAME, TILT-UP,

AND MASONRY BUILDINGS


Copyright


Publisher




SEAOC Board oversight of this publication was provided by 2012 SEAOC Board President James Amundson, S.E., and Immediate Past President Doug Hohbach, S.E.

Editor


Disclaimer

While the information presented in this document is believed to be correct, neither SEAOC nor its member organizations, committees, writers, editors, or individuals who have contributed to this publication make any warranty, expressed or implied, or assume any legal liability or responsibility for the use, application of, and/or reference to opinions, fi ndings, conclusions, or recommendations included in this publication. The material presented in this publication should not be used for any specifi c application without competent examination and verifi cation of its accuracy, suitability, and applicability. Users of information from this publication assume all liability arising from such use.

First Printing: September 2013

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Errata Notifi cation

SEAOC has made a substantial effort to ensure that the information in this document is accurate. In the event that corrections or clarifi cations are needed, these will be posted on the SEAOC web site at www.seaoc.org and on the ICC web site at www.iccsafe.org.


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Table of Contents

Preface to the 2012 IBC SEAOC Structural/Seismic Design Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii

Preface to Volume 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix

Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii

How to Use This Document. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxi

Design Example 1

Four-story Wood Light-frame Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Design Example 2

Flexible Diaphragm Design. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

Design Example 3

Three Story Light-frame Multi-family Building Design Using Cold-formed Steel Wall Framing and Wood Floor and Roof Framing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

Design Example 4

Masonry Shear Wall Building . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245

Design Example 5

Tilt-up Building . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273

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Preface to the 2012 IBC SEAOC Seismic/Structural Design Manual

The IBC SEAOC Seismic/Structural Design Manual, throughout its many editions, has served the purpose of illustrating good seismic design and the correct application of building-code provisions. The manual has bridged the gap between the discursive treatment of topics in the SEAOC Blue Book (Recommended Lateral Force Requirements and Commentary) and real-world decisions that designers face in their practice.

The examples illustrate code-compliant designs engineered to achieve good performance under severe seismic loading. In some cases simply complying with building-code requirements does not ensure good seismic response. This manual takes the approach of exceeding the minimum code requirements in such cases, with discussion of the reasons for doing so.

Recent editions of the IBC SEAOC Seismic/Structural Design Manual have consisted of updates of previous editions, modifi ed to address changes in the building code and referenced standards. Many of the adopted standards did not change between the 2006 edition of the International Building Code and the 2009 edition. The 2012 edition, which is the one used in this set of manuals, represents an extensive change of adopted standards, with many substantial changes in methodology.

Additionally, this edition has been substantially revised. New examples have been included to address new code provisions and new systems, as well as to address areas in which the codes and standards provide insuffi cient guidance. Important examples such as the design of base-plate anchorages for steel systems and the design of diaphragms have been added.

This expanded edition comprises fi ve volumes:


Previous editions have been three volumes. This expanded edition contains more types of systems for concrete buildings and steel buildings. These are no longer contained in the same volume. Volumes 3 and 4 of the 2012 edition replace Volume 3 of the 2009 edition. Additionally, we have fulfi lled the long-standing goal of including examples addressing seismic isolation and supplemental damping. These examples are presented in the new Volume 5.





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Preface to Volume 2

Volume 2 of the 2012 IBC SEAOC Structural/Seismic Design Manual addresses the design of light-frame, concrete tilt-up, and masonry shear wall building systems for seismic loading. These include the illustration of the design requirements for the shear walls and diaphragms, as were illustrated in previous editions, and also important interfaces with the rest of the structure.

The design examples in this volume represent a range of structural systems and seismic systems. The design of each of these systems is governed by standards developed by the American Concrete Institute (ACI) and the American Wood Council (AWC). The methods illustrated herein represent approaches consistent with the ductility expectations for each system and with the desired seismic response. In most cases there are several details or mechanisms that can be utilized to achieve the ductility and resistance required, and the author of each example has selected an appropriate option. In many cases alternatives are discussed. This manual is not intended to serve as a building code, or to be an exhaustive catalogue of all valid approaches and details.

This manual is presented as a set of examples in which the engineer has considered the building-code requirements in conjunction with the optimal seismic response of the system. The examples follow the guidelines of the SEAOC Blue Book and other SEAOC recommendations. The examples are intended to aid conscientious designers in crafting designs that are likely to achieve good seismic performance consistent with expectations inherent in the requirements for the systems.

Four examples have been included in past editions of this manual and are updated in this edition: four-story wood light-frame structure, light-gage framed building on podium structure, masonry shear wall building, and tilt-up building with windows. One example—wood diaphragm—is new and is included in this edition of the manual.

Douglas ThompsonVolume 2 Manager

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Acknowledgements

Volume 2 of the 2012 IBC SEAOC Seismic/Structural Design Manual was written by a group of highly qualifi ed structural engineers, chosen for their knowledge and experience with structural engineering practice and seismic design. The authors are:

Douglas S. Thompson, S.E., S.E.C.B. – Volume Manager and Example 1 Doug Thompson has over 35 years of experience in designing of wood structures. He is author several publications in timber design including the WoodWorks publications: Four-story Wood-frame Structure over Podium Slab and Five-story Wood-frame Structure over Podium Slab. Doug has instructed license review classes in timber design for the PE and SE exams for 20 years. He is the 2013-2014 president of the Structural Engineers Association of Southern California and holds licenses in six states. www.stbse.com

John Lawson, S.E. – Examples 2 and 5Assistant Professor John Lawson has provided structural engineering consulting services for over 30 years, including overseeing more than 100 million square feet of low-sloped roof and tilt-up concrete engineering. He now teaches in the Architectural Engineering department at California Polytechnic State University in San Luis Obispo. John is the recipient of the 2006 Tilt-up Concrete Association’s David L. Kelly Distinguished Engineer Award. www.arce.calpoly.edu

Michael Cochran, S.E., S.E.C.B – Example 3Michael Cochran is an Associate Principal with Weidlinger Associates, Inc. in Marina del Rey, California, with over 25 years of design experience. He has an extensive background in the design of multi-story light-framed commercial and multifamily residential wood and cold-formed steel-stud buildings. He is a registered structural engineer in California, an active member of the AISC Connection Prequalifi cation Review Panel, a past president of the Structural Engineers Association of Southern California (SEAOSC), and incoming 2013-2014 president for the Structural Engineers Association of California.

Jeff Ellis, S.E. – Example 3Manager of Codes, Standards, and Special Projects for Simpson Strong-Tie Company Inc., he has more than 22 years of experience in the construction industry. Mr. Ellis manages the company code and standards involvement as well as code reports. Additionally, he is involved in product development and offers technical guidance to customers for connectors, fastening systems, and lateral systems. He was a practicing design engineer for commercial, residential, and forensic projects for more than nine years prior to joining Simpson Strong-Tie at the end of 2000. He has served on the Board of Directors for SEAOSC, as chair of the 2011 and 2012 SEAOSC Buildings At Risk Summit, as chair of the AISI COFS Lateral Design Subcommittee, as president of the CFSEI and authored the Cold-Formed Steel Engineers Institute’s (CFSEI) Design Guide: Cold-Formed Steel Framed Wood Panel or Steel Sheet Sheathed Shear Wall Assemblies.

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xii 2012 IBC SEAOC Structural/Seismic Design Manual, Vol. 2

Chukwuma G. Ekwueme, PhD, SE, LEED AP – Example 4Dr. Ekwueme is an Associate Principal with Weidlinger Associates, Inc. in Marina del Rey, California. He has an extensive background in the design and analysis of a wide variety of structures, including concrete and masonry construction, steel and aluminum structures, and light-framed wood buildings. He is a registered Structural Engineer in California and Nevada and is an active member of the main committee, the seismic subcommittee, and the axial fl exural loads and shear subcommittee of the Masonry Standards Joint Committee (MSJC).

Additionally, a number of SEAOC members and other structural engineers helped check the examples in this volume. During its development, drafts of the examples were sent to these individuals. Their help was sought in review of code interpretations as well as detailed checking of the numerical computations. The reviewers include:

James Lai, S.E.

Alan Robinson, S.E.

Tim Stafford, S.E.

Doug Thompson, S.E.

Tom VanDorpe, S.E.

Close collaboration with the SEAOC Seismology Committee was maintained during the development of this document. The Seismology Committee has reviewed the document and provided many helpful comments and suggestions. Their assistance is gratefully acknowledged.


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References

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Western Wood Products Association (WWPA), November 2002, Tech Notes Report No. 10-Shrinkage Calculations for Multi-Story Wood Frame Construction, Portland, Oregon.

WWPA, 1990, Dimensional Stability of Western Lumber, Portland, Oregon.

Yousefi , Ben, Son, James, and Sabelli, Rafael, 2005. Structural Engineering Review Manual (2005 Edition), BYA Publications, Santa Monica, California.

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Design Example 1 Four-story Wood Light-frame Structure

OVERVIEW

This design example illustrates the seismic design of selected elements for a four-story wood-frame hotel structure. The gravity-load framing system consists of wood-frame bearing walls. The lateral-load-resisting system consists of wood-framed bearing shear walls (common box-type system). A typical building elevation and fl oor plan of the structure are shown in Figures 1-1 and 1-2 respectively. A typical section showing the heights of the structure is shown in Figure 1-3. The wood roof is framed with pre-manufactured wood trusses. The fl oor is framed with prefabricated wood I-joists. The fl oors have a 1½-inch lightweight concrete topping. The roofi ng is composition shingles.

When designing this type of “mid-rise” wood-frame structure, there are several unique design elements to consider. The following steps provide a detailed analysis of some of the important seismic requirements of the shear walls per the 2012 IBC. This design example represents a very simple wood-framed wood structure; most wood-framed structures have several unique features requiring engineering design and detailing not shown in this design example.

This design example is not a complete building design. Many aspects have not been included, specifi cally the gravity-load framing system, and only certain steps of the seismic design related to portions of a selected shear wall have been illustrated. In addition, the lateral requirements for wind design related to the selected shear wall have not been illustrated (only seismic). The steps that have been illustrated may be more detailed than what is necessary for an actual building design but are presented in this manner to help the design engineer understand the process. For a more detailed listing of the items not addressed see Section 10.

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Design Example 1 ◾ Four-story Wood Light-frame Structure

OUTLINE

1. Building Geometry and Loads

2. Calculation of the Design Base Shear

3. Location of Shear Walls and Diaphragms

4. Mechanics of Multi-story Segmented Shear Walls and Load Combinations

5. Mechanics of Multi-story Shear Walls with Force Transfer around Openings

6. The Envelope Process

7. Design and Detailing of Shear Wall at Line C

8. Diaphragm Defl ections to Determine if the Diaphragm is Flexible

9. Special Inspection and Structural Observation

10. Items Not Addressed in This Example

1. Building Geometry and Loads ASCE 7

1.1 GIVEN INFORMATION

The roof is 15/32-inch-thick DOC PS 1- or DOC PS 2-rated sheathing, with a 32/16 span rating and Exposure I glue.

The fl oor is 23/32-inch-thick DOC PS 1- or DOC PS 2-rated Sturd-I-Floor 24 inches o.c. rating, with a 48/24 span rating (40/20 span rating with topping is also acceptable) and Exposure I glue.

DOC PS 1 and DOC PS 2 are the U.S. Department of Commerce (DOC) Prescriptive and Performance-based standards for plywood and oriented strand board (OSB), respectively.

Wall framing is a “modifi ed balloon framing” where the joists hang from the walls in joist hangers. (See Figure 1-7 detail of this and an explanation of other common framing conditions.)

Framing lumber for studs and posts NDS T 4A




Douglas Fir Larch-No. 1 Grade:

Fb = 1,000 psi

Fc = 1,500 psi

Ft = 675 psi

E = 1,700,000 psi

Emin = 620,000 psi

Cm = 1.0

Ct = 1.0

Common wire nails are used for shear walls, diaphragms, and straps. When specifying nails on a project, specifi cation of the penny weight, type, diameter, and length (example 10d common = 0.148 inch × 3 inches) are recommended.

Figure 1–1. Building elevation




Figure 1–2. Typical foundation plan




Figure 1–3. Typical fl oor framing plan




Figure 1–4. Typical roof framing plan

Notes for Figure 1-2 through 1-4:

1. Non-structural “pop-outs” on the exterior walls at lines 1, 4 need special detailing showing the wood structural panel sheathing running continuous at lines 1, 4 and the pop-outs framed after the sheathing is installed.

2. All walls stack from the foundation to the fourth fl oor.

3. Designates sheathed wall per shear-wall schedule (see Table 1-32).


2012 IBC®


Volume 3EXAMPLES FOR CONCRETE BUILDINGS

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Publisher


The Structural Engineers Association of California (SEAOC) is a professional association of four regional member organizations (Central California, Northern California, San Diego, and Southern California). SEAOC represents the structural engineering community in California. This document is published in keeping with SEAOC’s stated mission:



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First Printing: August 2013

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Table of Contents


Preface to Volume 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix


References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii

How to Use This Document. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii

Design Example 1

Reinforced Concrete Wall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Design Example 2

Reinforced Concrete Wall with Coupling Beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Design Example 3

Reinforced Concrete Special Moment Frame . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Design Example 4

Reinforced Concrete Parking Garage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

Design Example 5

Pile Foundation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173

Design Example 6

Design of Concrete Diaphragm and Collector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220

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The IBC SEAOC Structural/Seismic Design Manual, throughout its many editions, has served the purpose of illustrating good seismic design and the correct application of building-code provisions. The manual has bridged the gap between the discursive treatment of topics in the SEAOC Blue Book (Recommended Lateral Force Requirements and Commentary) and real-world decisions that designers face in their practice.


Recent editions of the IBC SEAOC Structural/Seismic Design Manual have consisted of updates of previous editions, modifi ed to address changes in the building code and referenced standards. Many of the adopted standards did not change between the 2006 edition of the International Building Code and the 2009 edition. The 2012 edition, which is the one used in this set of manuals, represents an extensive change of adopted standards, with many substantial changes in methodology.









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Preface to Volume 3

Volume 3 of the 2012 IBC SEAOC Structural/Seismic Design Manual illustrates the design requirements for reinforced concrete shear wall and moment-frame seismic systems, and also important interfaces with the rest of the structure.

The design examples in this volume represent a range of structural systems and seismic systems. The design of each of these systems is governed by standards developed by the American Concrete Institute (ACI) in ACI-318. The methods illustrated herein represent approaches consistent with the ductility expectations for each system and with the desired seismic response. In most cases there are several details or mechanisms that can be utilized to achieve the ductility and resistance required, and the author of each example has selected an appropriate option. In many cases alternatives are discussed. This manual is not intended to serve as a building code, nor to be an exhaustive catalogue of all valid approaches and details.

The manual is presented as a set of examples in which the engineer has considered the building-code requirements in conjunction with the optimal seismic response of the system. The examples follow the recommendations of the SEAOC Blue Book and other SEAOC recommendations. The examples are intended to aid conscientious designers in crafting designs that are likely to achieve good seismic performance consistent with expectations inherent in the requirements for the systems.

Three examples have been included in past editions of this manual and are updated in this edition: reinforced concrete shear wall, reinforced concrete shear wall with coupling beams, and reinforced concrete special moment frame. Three examples are new and are included in this edition of the manual: reinforced concrete parking garage, reinforced concrete pile foundation, and reinforced concrete diaphragms and collectors.

Jon KilandVolume 3 Manager

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Acknowledgements

Volume 3 of the 2012 IBC SEAOC Structural/Seismic Design Manual was written by a group of highly qualifi ed structural engineers, chosen for their knowledge and experience with structural engineering practice and seismic design. The authors are:

Joe Maffei, S.E., Ph.D., LEED AP, Principal, Maffei Structural Engineering—Examples 1 and 2With 29 years of experience in research and practice, Joe is an expert on the seismic evaluation, design, and retrofi tting of structures. He has directed a range of projects, including those using innovative solutions and advanced methods of evaluation. The American Society of Civil Engineers and the American Concrete Institute have appointed Joe to committees writing structural code provisions. www.maffei-structure.com

Karl Telleen, S.E., Maffei Structural Engineering—Examples 1 and 2Karl joined Rutherford + Chekene Consulting Engineers in San Francisco in 2004, and his experience includes seismic retrofi t of concrete buildings as well as design of new structures. Mr. Telleen joined MSE in 2013. He completed a Fulbright Fellowship in Switzerland in 2010, and he performed post-earthquake reconnaissance in Haiti following the January 2010 earthquake. He is currently participating in the ATC-94 project studying the performance of concrete buildings in the 2010 Chile earthquake. www.maffei-structure.com

Jon Kiland, S.E., Applied Technology Council—Volume 3 Manager and Example 3Jon has 33 years of experience as a structural design and consulting engineer in Northern California. His practice has included extensive experience in seismic analysis and evaluation of existing buildings, the design of new construction, and the seismic strengthening and rehabilitation of existing building projects. He currently works for the Applied Technology Council in Redwood City, California, as Director of Projects involved with developing advanced engineering applications for natural hazard mitigation. He has been actively involved in the development of codes and standards for over 25 years.

He is a Past President of the Structural Engineers Association of California and the Structural Engineers Association of Northern California, and a Fellow Member of both organizations. His current committee assignments include the ASCE 7-16 Seismic Sub-Committee (SSC) and Chair of the TC-2 General Provisions Task Committee. www.atcouncil.org

Jeremiah LeGrue, S.E., Hohbach-Lewin, Inc. Structural Engineers—Example 4.Jeremiah has been with Hohbach-Lewin since 2002 and works in their Eugene, Oregon, offi ce. His experience includes analysis and design of concrete structures using traditional and performance-based methods. Prior to joining Hohbach-Lewin, Jeremiah developed probabilistic hazard assessments and loss models for the re-insurance industry. He is a registered Structural Engineer in California and Oregon. Jeremiah has a Masters in Structural Engineering from Stanford University. www.hohbach-lewin.com

Stephen Harris, S.E., Principal, Simpson Gumpertz & Heger Inc.—Example 5Stephen Harris has practiced structural engineering for over 26 years. He is a graduate of the University of California at Davis and a registered Structural Engineer in California, Oregon, and Hawaii. His experience includes design of new structures, seismic strengthening of existing structures and design of pile foundation systems. www.sgh.com

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Badri Prasad, S.E., Vice President, TTG Engineers—Example 6Badri received his BS degree from Bangalore University, India, and MS degree from Mysore University, India. He also obtained his MS degree from the University of Arizona. He is currently a Vice President and Branch Manager—Structural at TTG Engineers, San Francisco, California. He is a registered SE in California and registered PE in Washington State. He has 25 years of experience in the design of various types of structures, such as healthcare facilities, biotechnology facilities, mid- and high-rise structures, schools, and seismic retrofi t, among others. He is a member of the SEAONC Seismology Committee’s concrete subcommittee and was instrumental in publishing the committee’s work titled “Concrete Slab as a Collector Element” in the 2008 SEAOC Blue Book. He is also the project manager for this guide. He has published several papers on buckling restrained braced frames and a research paper on base-isolation system.


Russell Berkowitz

Anindya Dutta

Tim Hart

Mark Jokerst

Jon Kiland

Yixia Liu

Ted Zsutty



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References

Standards

ACI 318, 2011, Building Code Regulations for Reinforced Concrete, American Concrete Institute, Farmington Hills, Michigan.

ASCE/SEI 7, 2010, Minimum Design Loads for Buildings and Other Structures, American Society of Civil Engineers, Structural Engineering Institute, Reston, Virginia.

ICC, 2012, International Building Code (IBC). International Code Council, Washington, DC.

Other References

Adebar, P., Ibrahim, A.M.M., and Bryson, M., 2007, Test of High-Rise Core Wall: Effective Stiffness for Seismic Analysis, ACI Structural Journal, American Concrete Institute, Farmington, Michigan, September-October 2007.

AISC, 2003, Design guide 18—Steel-framed open-deck parking structures., American Institute of Steel Construction, Chicago, Illinois.

ASCE/SEI 41-06, 2007, Seismic Rehabilitation of Existing Buildings, Structural Engineering Institute of the American Society of Civil Engineers, Reston, Virginia.

ASCE, 1971, Plastic Design in Steel, A Guide and Commentary, American Society of Civil Engineers, New York, New York.

ATC, 1996, ATC-40, Seismic Evaluation and Retrofi t of Concrete Buildings, Applied Technology Council, Redwood City, California.

CRSI, 1996, Rebar Design and Detailing Data—ACI., Concrete Reinforcing Steel Institute, Schaumberg, Illinois.

Elwood, Kenneth J., Joe Maffei, Kevin A. Riederer, and Karl Telleen, 2009, Improving Column Confi nement Part 2: Proposed new provisions for the ACI 318 Building Code, Concrete International, Volume 31, No. 12, pages 41–48, December 2009.

Elwood, Kenneth J., Joe Maffei, Kevin A. Riederer, and Karl Telleen, 2009, Improving Column Confi nement Part 1: Assessment of design provisions, Concrete International, Volume 31, No. 11, pages 32–48, November 2009.

Evaluation of Earthquake Damaged Concrete and Masonry Wall Buildings, prepared by the Applied Technology Council (ATC-43 project) for the Partnership for Response and Recovery. Federal Emergency Management Agency, Report No. FEMA-306, Washington, D.C., 1999.

FEMA, 1998, FEMA 306/307, Evaluation of Earthquake Damaged Concrete and Masonry Wall Buildings, Federal Emergency Management Agency, Washington, D.C.

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xiv 2012 IBC SEAOC Structural/Seismic Design Manual, Vol. 3

Ghosh, S. K., 1998, Design of Reinforced Concrete Buildings under the 1997 UBC, Building Standards, May-June, pp. 20–24. International Conference of Building Offi cials, Washington, D.C.

Guzman T. and M. Abell. (2012, April 17). Modeling cracked shear-wall behavior. Retrieved from https://wiki.csiberkeley.com/x/AoBF

Jirsa, J.O., L.A. Lutz, and P. Gergely, 1979. Rationale for Suggested Development, Splice, and Standard Hook Provisions for Deformed Bars in Tension, Concrete International: Design & Construction, Vol. 1, No. 7, July 1979, pp. 47–61.

Maffei, Joe, 1996, Reinforced Concrete Structural Walls—Beyond the Code, SEAONC Fall Seminar Proceedings. Structural Engineers Association of Northern California, San Francisco, California, November, 1996.

McCormac J.C.. 1992, Design of Reinforced Concrete, Third Edition, Harper Collins College Publishers, New York, New York.

MacGregor, J.G., 1992, Second Edition, Reinforced Concrete Mechanics and Design, Prentice Hall, New Jersey.

Nilson, A.H. and Winter, G., 1966, Design of Concrete Structures, Tenth Edition, McGraw-Hill Book Company, New York, New York.

Pacifi c Earthquake Engineering Research Center (PEER), 2010, Tall Buildings Initiative: Guidelines for Performance-Based Seismic Design of Tall Buildings, Version 1.0, University of California, Berkeley, California, November, 2010.

Paulay, T., and Priestley, M.J.N. 1992, Reinforced Concrete and Masonry Buildings, Design for Seismic Resistance. John Wiley & Sons, Inc., New York, New York.

Paulay, T., and Priestley, M.J.N. 1993, Stability of Ductile Structural Walls. ACI Structural Journal, Vol. 90, No. 4, July-August 1993.

Reese, L.C., Isenhower, W.M., Wang, S-T, 2006, Analysis and Design of Shallow and Deep Foundations, John Wiley & Sons, Inc., Hoboken, New Jersey.

Schotanus, M. IJ., and Maffei, J.R., 2007, Computer Modeling and Effective Stiffness of Concrete Wall Buildings, Proceedings of the International FIB Symposium on Tailor Made Concrete Structures: New Solutions for Our Society, CRC Press, Leiden, The Netherlands, May 2007.

SEAOC Blue Book, 1999, Recommended Lateral Force Requirements and Commentary, Structural Engineers Associate of California (SEAOC), Seventh Edition, Sacramento, California.

SEAOC Blue Book, 2009, Reinforced Concrete Structures (Article 09.01.010). Recommended Lateral Force Requirements and Commentary, Structural Engineers Associate of California, Sacramento, California, First Printing, September, 2009.

SEAOC Blue Book, 2008, Concrete slab collectors, Recommended Lateral Force Requirements and Commentary, Structural Engineers Association of California, Sacramento, California.

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Standards New Zealand, 1995, Concrete Structures Standard: Part 2—Commentary on the Design of Concrete Structures (NZS 3101: Part 2)., May 1995, p. 84.

Structurepoint. 2010, SPcolumn Version 4.60: Design and Investigation of Reinforced Concrete Column Sections, STRUCTUREPOINT, Skokie, Illinois.

Schotanus, M. IJ., and Maffei, J.R. 2007, Computer Modeling and Effective Stiffness of Concrete Wall Buildings, Proceedings of the International FIB Symposium on Tailor Made Concrete Structures: New Solutions for Our Society, CRC Press, Leiden, The Netherlands, May 2007.

USGS, 2012, U.S. Seismic Design Maps Web Application, Retrieved from http://geohazards.usgs.gov/designmaps/us/application.php. United States Geological Survey, Washington, D.C.

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Design Example 1Reinforced Concrete Wall

OVERVIEW

The structure in this design example is an eight-story offi ce with load-bearing reinforced concrete walls as its seismic-force-resisting system. This design example focuses on the design and detailing of one of the 30-foot, 6-inch-long walls running in the transverse building direction.

The purpose of this design example is twofold:

1. To demonstrate the design of a solid reinforced concrete wall for fl exure and shear, including bar cut-offs and lap splices.

2. To demonstrate the design and detailing of wall boundary zones.

The design example assumes that design lateral forces have already been determined for the structure and that the forces have been distributed to the walls of the structure by a hand or computer analysis. This analysis has provided the lateral displacements corresponding to the design lateral forces.

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Design Example 1 � Reinforced Concrete Wall

OUTLINE


2. Load Combinations for Design

3. Preliminary Sizing of Wall

4. Flexural Strength at Base of Wall

5. Flexural Strength and Lap Splices over Height of Wall

6. Shear Strength of Wall

7. Shear Friction (Sliding Shear) Strength of Wall

8. Detailing of Wall Boundary Elements

1. Building Geometry and Loads ASCE 7


This design example follows the general building code requirements of the 2012 International Building Code (2012 IBC) and ASCE 7. For structural concrete design, the 2012 IBC references the American Concrete Institute Building Code (ACI 318) as indicated in Section 1901.2. This example follows the requirements of ACI 318-11. Discussions related to the SEAOC Blue Book recommendations refer to the document Recommended Lateral Force Recommendations and Commentary (SEAOC, 1999) as well as the Blue Book online articles on specifi c topics (SEAOC, 2009) as applicable.

Figure 1–1 shows the typical fl oor plan of the structure. The design and analysis of the structure is based on a response modifi cation coeffi cient, R, of 5 (ASCE 7 Table 12.2–1) for a bearing wall system with special reinforced concrete shear walls. The defl ection amplifi cation factor, Cd, is 5. The SEAOC Blue Book (2009, Article 09.01.010) expresses the opinion that the R value for concrete bearing-wall systems (R = 5) and that for walls in building frame systems (R = 6) should be the same, which may be justifi ed based on detailing provisions. To be consistent with the current code requirements though, this design example uses R = 5.

Mapped spectral response acceleration values from ASCE 7 maps (Figures 22–1 through 22–11) are

• S1 = 0.65

• SS = 1.60

• Site Class D

• Risk Category II




• Seismic Design Category D

• Redundancy factor, ρ = 1.0

• Seismic Importance factor, I = 1.0

• Concrete strength, ′fcff = 5000 psi

• Steel yield strength, fy = 60 ksi

Figure 1–1. Floor plan

1.2 DESIGN LOADS AND LATERAL FORCES

Figure 1–2 shows the wall elevation and shear and moment diagrams. The wall carries axial forces PD (resulting from dead load including self-weight of the wall) and PL (resulting from live load) as shown in Table 1–1. Live loads have already been reduced according to IBC Section 1607.10. The shear, VE, and moment, ME, resulting from the design lateral earthquake forces are also shown in Table 1–1. The forces are from a linear static analysis.




Figure 1–2. Wall elevation, shear, and moment diagram

Table 1–1. Design loads and lateral forces

Level PD (kips) PL (kips) VE (kips) ME (kip-ft)

Roof 193 37 84 0

8 388 72 244 928

7 573 108 414 3630

6 758 144 595 8210

5 945 181 785 14,800

4 1130 217 987 23,500

3 1310 253 1220 34,400

2 1540 290 1420 48,000

1 73,000




For this design example, it is assumed that the foundation system is rigid, and thus the wall is considered to have a fi xed base. The fi xed-base assumption is made here primarily to simplify the example. In an actual structure, the effect of foundation fl exibility and its consequences on structural deformations should be considered.

The analysis uses effective section properties for the stiffness of concrete elements. Example 2 includes a discussion of effective section properties for use in analysis.

Using the fi xed-base assumption and effective section properties, the horizontal displacement at the top of the wall corresponding to the design lateral forces is 1.55 inches. This displacement is needed for the detailing of boundary zones according to ACI 318 Section 21.9.6, which is illustrated in Part 8 of this design example.

2. Load Combinations for Design ASCE 7

2.1 LOAD COMBINATIONS

Load combinations for the seismic design of concrete are given in Section 2.32. (This is indicated in Section 12.4.2.3.) Equations 5 and 7 of Section 2.3.2 are the seismic design load combinations to be used for concrete.

1.2D + 1.0E + L + 0.2S

0.9D + 1.0E.

Load combinations for non-seismic loads for reinforced concrete are given in Section 2.3.2, Equations 1, 2, 3, 4, and 6.

2.2 HORIZONTAL AND VERTICAL COMPONENTS OF EARTHQUAKE FORCE

The term E in the load combinations includes horizontal and vertical components according to Equations 12.4–1 and 12.4–2 of Section 12.4.2:

E = Eh + Ev Eq 12.4–1

E = Eh − Ev Eq 12.4–2

where Eh and Ev are defi ned according to Equations 12.4–3 and 12.4–4 of Section 12.4.2.1 and Section 12.4.2.2 as follows:

Eh = ρQE Eq 12.4–3

Ev = 0.2SDSD. Eq 12.4–4

Substituting this into the seismic-load combinations results in

(1.2 + 0.2SDS)D + ρQE + L + 0.2S

(0.9 − 0.2SDS)D + ρQE.


2012 IBC®


Volume 4EXAMPLES FOR STEEL-FRAMED BUILDINGS

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Copyright


Publisher





Editor


Disclaimer


First Printing: August 2013

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Table of Contents


Preface to Volume 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix


References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv

How to Use This Document. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xix

Design Example 1

Special Moment Frame . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Design Example 2

Special Concentrically Braced Frame . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Design Example 3

Buckling-Restrained Braced Frame . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Design Example 4

Special Plate Shear Walls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

Design Example 5

Eccentrically Braced Frame . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

Design Example 6

Multi-Panel OCBF. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189

Design Example 7

Metal Deck Diaphragm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

a. Bare Metal Deck (Flexible) Diaphragm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215

b. Concrete-Filled Deck (Rigid) Diaphragm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239

Design Example 8

Special Moment Frame Base Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255

Design Example 9

Braced-Frame Base Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281

Appendix 1: General Building Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295

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The IBC SEAOC Structural/Seismic Design Manual, throughout its many editions, has served the purpose of illustrating good seismic design and the correct application of building-code provisions. The manual has bridged the gap between the discursive treatment of topics in the SEAOC Blue Book (Recommended Lateral Force Requirements and Commentary) and real-world decisions that designers face in their practice.


Recent editions of the IBC SEAOC Structural/Seismic Design Manual have consisted of updates of previous editions, modifi ed to address changes in the building code and referenced standards. Many of the adopted standards did not change between the 2006 edition of the International Building Code and the 2009 edition. The 2012 edition, which is the one used in this set of manuals, represents an extensive change of adopted standards, with many substantial changes in methodology.









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Preface to Volume 4

Volume 4 of the 2012 IBC SEAOC Structural/Seismic Design Manual addresses the design of steel building systems for seismic loading. Examples include the illustration of the design requirements for braced frames and moment frames, as were illustrated in previous editions, and also important interfaces with the rest of the structure.

The design examples in this volume represent a range of steel structural systems. The Manual includes a set of examples that illustrate a more complete design: the design of diaphragms and collectors is illustrated, as are the design of base plates and anchorages for moment-frame and braced-frame columns. With the addition of these items this edition of the Manual offers more extensive guidance to engineers, addressing the design of these critical components of the seismic system.

The design of each of these systems is governed by standards developed by the American Institute of Steel Construction (AISC). AISC produces its own Seismic Design Manual to illustrate the correct application of the AISC Seismic Provisions (AISC 341) and the AISC Prequalifi cation Standard (AISC 358). The AISC Seismic Design Manual is a valuable resource for designers, and this volume is not intended to duplicate AISC’s efforts. This manual, for example, does not include the detailed range of options for gusset-plate design, as the AISC Seismic Design Manual addresses this design aspect thoroughly.

Nevertheless, there is a fundamental difference in purpose and approach between this manual and the AISC Seismic Design Manual. The AISC Manual illustrates the code requirements, while the SEAOC Structural/Seismic Design Manual illustrates SEAOC’s recommended practices, which traditionally have gone beyond the code (or in advance of it). The design examples for base plates are important examples of design methodologies not explicitly defi ned by building codes. Building code provisions for these connections are diffi cult to apply and do not correspond well to the mechanisms of resistance. The examples herein provide a convenient and valuable alternative methodology, one that is not an illustration of explicit code requirements.

The methods illustrated herein represent approaches consistent with the ductility expectations for each system and with the desired seismic response. In most cases there are several details or mechanisms that can be utilized to achieve the ductility and resistance required, and the author of each example has selected an appropriate option. In many cases alternatives are discussed. This Manual is not intended to serve as a building code or to be an exhaustive catalogue of all valid approaches and details.

The Manual is presented as a set of examples in which the engineer has considered the building-code requirements in conjunction with the optimal seismic response of the system. The examples follow the recommendations of the SEAOC Blue Book and other SEAOC recommendations. The examples are intended to aid conscientious designers in crafting designs that are likely to achieve good seismic performance consistent with expectations inherent in the requirements for the systems.

Rafael SabelliVolume 4 Manager

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Acknowledgements

Volume 4 of the 2012 IBC SEAOC Structural/Seismic Design Manual was written by a group of highly qualifi ed structural engineers, chosen for their knowledge and experience with structural engineering practice and seismic design.

Kevin S. Moore, S.E., SECB, Principal, Simpson Gumpertz & Heger—Examples 1 and 8With multiple state licenses, Kevin has more than 18 years of experience in structural engineering design, analysis, and evaluation. He is the Chair of the SEAOC Structural Standards Committee, Past Chair of the SEAOC Seismology Committee, and Chair of the Seismic Subcommittee of the NCSEA Code Advisory Committee. He has written multiple papers and design examples associated with steel design, seismic forces, and structural systems. Kevin is also a member of the AISC Connection Prequalifi cation Review Panel. www.sgh.com

Rafael Sabelli, S.E., Principal, Director of Seismic Design, Walter P. Moore—Volume 4 Manager and Example 2Rafael Sabelli is a member of the AISC Task Committee on the Seismic Provisions for Structural Steel Buildings, Chair of the AISC Seismic Design Manual committee, a member of the ASCE 7 Seismic subcommittee, and a member of the BSSC Provisions Update Committee and Code Resource Support Committee. He is the coauthor (with Michel Bruneau) of AISC Design Guide 20: Steel Plate Shear Walls as well as of numerous research papers on conventional and buckling-restrained braced frames. He has served as Chair of the Seismology Committee of the Structural Engineers Association of California and as President of the Structural Engineers Association of Northern California. Rafael was the co-recipient of the 2008 AISC T.R. Higgins Lectureship and was the 2000 NEHRP Professional Fellow in Earthquake Hazard Reduction.

Anindya Dutta, S.E., Ph.D, Simpson Gumpertz & Heger—Example 3Dr. Dutta has over 12 years of experience in structural and earthquake engineering. He has provided analysis and design of a variety structures in high seismic zones. Dr. Dutta’s experience also includes seismic evaluation and strengthening of low-rise to high-rise structures. He has taught graduate and undergraduate level courses on concrete design and structural analysis at the State University of New York at Buffalo and is a regular lecturer at the San Francisco State University’s graduate program and at the University of California at Berkeley’s extension program. He has authored a number of technical reports and journal papers as well as served as a member of the review board for ASCE’s Structural Engineering Journal.

Kenneth Tam, Simpson Gumpertz & Heger—Example 3Kenneth has more than 17 years of experience in the fi eld of structural and earthquake engineering. His experience includes structural design and evaluation of variety of structures in high seismic zones. He has co-authored various papers on design and analysis of buckling-restrained braced frames and has served on the ASCE41-13 Steel Subcommittee.

Matthew R. Eatherton, Ph.D., S.E., Assistant Professor, Virginia Tech—Example 4Matt has seven years of experience as a practicing structural engineer conducting high-seismic design in the San Francisco Bay Area. Now he serves on the faculty at Virginia Tech where he teaches classes on steel design, structural dynamics, and earthquake engineering. His research program includes both experimental and computational investigations of steel-plate shear walls, self-centering seismic systems, steel connections, and more. www.eatherton.cee.vt.edu

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Scott M. Adan, Ph.D., P.E., S.E., SECB, Principal, Adan Engineering—Example 5With over 21 years of experience, Dr. Adan specializes in the investigation and design of buildings and structures. He is also actively involved in the research and development of steel moment-resisting connections. For the Structural Engineers Association of Northern California, he chairs the Steel Subcommittee. For the American Institute of Steel Construction, he is a member of the Seismic Design Manual Subcommittee, the Connection Prequalifi cation Review Panel, and the Seismic Design Task Committee. www.adanengineering.com

Anna Dix, S.E., Associate, Liftech Consultants Inc.—Example 6Anna has eight years of practice in design and analysis of steel and concrete structures. Her focus is on special-use and marine structures including cranes, wharves, and heavy-lift and container-handling equipment. She has specialized experience with ductile tie-down systems for cranes, seismic design and analysis of steel structures, seismic crane-wharf interaction, designing ductile steel frames, and investigating fatigue cracking for various structures. In her spare time, Anna introduces engineering to inquisitive young minds. www.liftech.net

Katy Briggs, S.E., Project Engineer, Thornton Tomasetti—Example 7A licensed S.E. in the State of California, Katy Briggs has seven years of experience in structural analysis and design. She has worked on new buildings and seismic retrofi ts of existing buildings utilizing wood, steel, concrete, and masonry construction. These projects include education, healthcare, government, correctional, and commercial facilities. She has been involved with writing and editing design examples for steel diaphragms and special concentrically braced frames.

Amit Kanvinde, Ph.D., Associate Professor of Civil and Environmental Engineering, University of California, Davis—Example 8Amit’s research heavily focuses on the seismic response of steel structures and connections through experimentation and simulation. Pertinent to the design example, he has conducted 28 large-scale tests on column base connections and is the author of two major technical reports and several journal and conference papers on the topic of base plates. His other recent research has addressed the fracture of seismic column splices in moment frames and braces in SCBF systems. He is the recipient of the 2008 ASCE Norman Medal and the 2003 EERI Graduate Student Paper award addressing the collapse of structures.

David A. Grilli, M.S., E.I.T., Graduate Student Researcher, University of California, Davis—Example 8David is a doctoral student in the Department of Civil and Environmental Engineering at UC Davis. Through large-scale experimentation, his work addresses the seismic response of embedded and exposed column-base plates. Pertinent to this example, he is co-author of a journal article that characterizes the rotational fl exibility of exposed column base connections. David was the recipient of the AISC Structural Steel Education Council scholarship in 2009, and the Farrer/Patten Award for outstanding student in Civil Engineering at UC Davis in 2012.

Lindsey Maclise, Associate, Forell/Elsesser Engineers Inc.—Example 9Lindsey is currently an Associate with Forell/Elsesser Engineers specializing in seismic design for both new construction and retrofi t. She received her B.S. and M.S. from the University of California, Berkeley and is an active member of SEAONC, SEI, and EERI. She is currently serving as a Housner Fellow for her work in Sustainable Seismic Design. www.forell.com

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Geoff Bomba

Mike Cochran

Andrew Cussen

Tom Hale

Walterio López

Sara Jozefi ak

Ryan Kersting

Benjamin Mohr

Carrie Leung

Thomas Nunziata

Patxi Uriz

Laura Whitehurst



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References

Standards

American Concrete Institute. ACI 318: Building Code Regulations for Reinforced Concrete, Farmington Hills, Michigan, 2011.

American Institute of Steel Construction. AISC 341: Seismic Provisions for Structural Steel Buildings, Chicago, Illinois, 2010.

American Institute of Steel Construction. AISC 358: Prequalifi ed Connections for Special and Intermediate Steel Moment Frames for Seismic Applications, Chicago, Illinois, 2010.

American Institute of Steel Construction. AISC 360: Specifi cation for Structural Steel Buildings, Chicago, Illinois, 2010.

American Society of Civil Engineers. ASCE 7: Minimum Design Loads for Buildings and Other Structures. ASCE 2010.

International Code Council. International Building Code (IBC). Falls Church, Virginia, 2012.

Other References

American Institute of Steel Construction. Manual of Steel Construction, Chicago, Illinois, 2012.

American Institute of Steel Construction. Seismic Design Manual, Chicago, Illinois, 2013.

Anonymous, 1977. “Shear walls and slipforming speed Dallas’ Reunion project” Engineering News Record, 20–21, July 28.

Anonymous, 1978a. “Patent problems, challenge spawn steel seismic walls” Engineering News Record, 17, January 26.

Anonymous, 1978b. “Quake-proof hospital has battleship-like walls” Engineering News Record, 62–63, Sept. 21.

Astaneh-Asl, A. 2005. “Design of Shear Tab Connections for Gravity and Seismic Loads,” Steel Technical Information and Product Report. Structural Steel Educational Council, CA.

Basler, K. 1961. “Strength of Plate Girders in Shear” Journal of the Structural Division, ASCE, Vol. 87, No. ST7 October.

Berman, J. W. and Bruneau, M. 2004. “Steel Plate Shear Walls are Not Plate Girders” AISC Engineering Journal, Third Quarter.

Berman, J. W. and Bruneau, M. 2008. “Capacity Design of Vertical Boundary Elements in Steel Plate Shear Walls” AISC Engineering Journal, First Quarter.

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Bozorgnia, Y., Bertero, V., 2004. Earthquake Engineering: From Engineering Seismology to Performance-Based Engineering. CRC Press, LLC, Danvers, Massachusetts.

Bruneau, M., Uang, C.M., and Sabelli, R. Ductile Design of Steel Structures. McGraw-Hill, 2011.

CAN/CSA S16-09 2009. “Limit States Design of Steel Structures,” published by Canadian Standards Association.

Cheng, J.J.R., and Kulak, G.L. 2000. Gusset plate connection to round HSS tension members. Engineering Journal, AISC, 4th Quarter, 133–139.

Clifton, C., Bruneau, M., MacRae, G., Leon, R., Russell, A., 2011. “Steel Structures Damage from the Christchurch Earthquake of February 22, 2011,” NZST, Bulletin of the New Zealand Society for Earthquake Engineering, Vol. 44, No. 4.

DeWolf, J. T., and Ricker, D. T. 1990. AISC Design Guide 1—Column Base Plates, Published by the American Institute of Steel Construction, AISC.

Engelhardt, M., and Popov, E., 1989. “On Design of Eccentrically Braced Frames,” Earthquake Spectra, EERI, Vol. 5, No. 3, 495–511.

Englehardt, M. Personal correspondence and notes. 2012.

Fisher, J.M. and Kloiber, L.A. 2006. “Base Plate and Anchor Rod Design,” 2nd Ed., Steel Design Guide Series No. 1, American Institute of Steel Construction, Inc., Chicago, IL.

Gomez, I.R., Kanvinde A.M., and Deierlein G.G. 2010. “Exposed Column Base Connections Subjected to Axial Compression and Flexure,” Report Submitted to the American Institute of Steel Construction (AISC), Chicago, IL.

Gomez, I.R., Kanvinde, A.M., and Deierlein, G.G. 2011. “Experimental investigation of shear transfer in exposed column base connections,” Engineering Journal, American Institute of Steel Construction, 4th Quarter, 246–264.

ICC/SEAOC 2006. “Design Example 4—Steel Plate Shear Walls”, 2006 IBC Structural/Seismic Design Manual, Volume 3, Structural Engineers Association of California, Sacramento, California.

Imanpour, A., Tremblay, R., and Davaran, A. “Seismic Evaluation of Multi-Panel Steel Concentrically Braced Frames,” 15th World Conference on Earthquake Engineering, 2012.

Lehman, D., Roeder, C. 2, Johnston, S. 1, Herman D. 1, and Kotulka, B. 1 2008 “Improved Seismic Performance of Gusset Plate Connections”, ASCE Journal of Structural Engineering, Vol. 134, No. 6, 181–189.

Luttrell, Larry D. 1967. “Strength and behavior of light-gage steel shear diaphragms”, Cornell Research Bulletin 67-1, sponsored by the American Iron and Steel Institute, Ithaca, NY.

Moehle, Jack P., Hooper, John D., Kelly, Dominic J., and Meyer, Thomas. 2010. “Seismic design of cast-in-place concrete diaphragms, chords, and collectors: A guide for practicing engineers,” NEHRP Seismic Design Technical Brief Number 3, produced by the NEHRP Consultants Joint Venture, a partnership of the Applied Technology Council and the Consortium of Universities

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for Research in Earthquake Engineering, for the National Institute of Standards and Technology, Gaithersburg, MD, NIST GCR 10-917-4.

Moore, Kevin S., Feng, Joyce Y., June 2007. “Design of RBS Connections for Special Moment Frames,” Steel Tips. Structural Steel Educational Council, Moraga, California.

Myers, A.T., Kanvinde, A.M., Deierlein, G.G., and Fell B.V. 2009, “Effect of Weld Details on the Ductility of Steel Column Baseplate Connections,” Journal of Constructional Steel Research, Volume 65, Issue 6, June 2009, 1366–1373.

Porter, D.M., Rockey, K.C. and Evans, H.R. 1975. “The collapse behavior of plate girders loaded in shear”, The Structural Engineer, London England, Vol. 53, No. 8., Aug.

Prasad, Badri K., Thompson, Douglas S., and Sabelli, Rafael. 2009. Guide to the design of diaphragms, chords and collectors based on the 2006 IBC and ASCE/SEI 7-05, International Code Council Publications, Country Club Hills, IL.

Purba, R. and Bruneau, M. 2009. “Finite-Element Investigation and Design Recommendations for Perforated Steel Plate Shear Walls” Journal of Structural Engineering, Vol. 135, No. 11, 1367–1376.

Purba, R., and Bruneau, M. 2007. Design Recommendations for Perforated Steel Plate Shear Walls Technical Report MCEER-07-0011.

Qu, B., and Bruneau, M. 2010. “Capacity Design of Intermediate Horizontal Boundary Elements of Steel Plate Shear Walls” Journal of Structural Engineering, Vol. 136, No. 6.

Ricles, J., and Popov, E., 1989, “Composite Action in Eccentrically Braced Frames,” Journal of Structural Engineering, ASCE, Vol. 115, No. 8, 2046–2065.

Roberts, T. M. and Sabouri-Ghomi, S. 1991. “Hysteretic Characteristics of Unstiffened Plate Shear Panels” Thin-Walled Structures, Elsevier Science Publishers, Great Britain, 1991.

Rogers, C.A. and Tremblay, R. 2008. “Impact of Diaphragm Behavior on the Seismic Design of Low-Rise Steel Buildings”, AISC Engineering Journal, First Quarter.

Sabelli, R. and Bruneau, M. 2006. AISC Design Guide 20—Steel Plate Shear Walls, Published by the American Institute of Steel Construction, AISC.

Sabelli, Rafael, Sabol, Thomas A., and Easterling, Samuel W. 2011. “Seismic design of composite steel deck and concrete-fi lled diaphragms: A guide for practicing engineers,” NEHRP Seismic Design Technical Brief Number 5, produced by the NEHRP Consultants Joint Venture, a partnership of the Applied Technology Council and the Consortium of Universities for Research in Earthquake Engineering, for the National Institute of Standards and Technology, Gaithersburg, MD, NIST GCR 10-917-10.

Schumacher, A., Grondin, G.Y. and Kulak, G.L. 1999. “Connection of Infi ll Panels in Steel Plate Shear Walls” Canadian Journal of Civil Engineering, Vol. 26.

SDI 2004. Diaphragm design manual, Third Edition (SDI DDMO3), Steel Deck Institute, Fox Grove, IL.

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xviii 2012 IBC SEAOC Structural/Seismic Design Manual, Vol. 4

SEAOC Blue Book, Recommended Lateral Force Requirements and Commentary. Structural Engineers Association of California, Sacramento, California.

SEAOC Seismology Committee 2007. “Development of System Factors,” May 2007, The SEAOC Blue Book: Seismic design Recommendations, Structural Engineers Association of California, Sacramento, CA.

SEAOC Seismology Committee 2008. “Concentrically Braced Frames,” August, 2008, The SEAOC Blue Book: Seismic Design Recommendations, Structural Engineers Association of California, Sacramento, CA. Accessible via the world wide web at: http://www.seaoc.org/bluebook/index.html

SEAOC Seismology Committee, FEMA 350 Task Group, 2002. “Commentary and Recommendations on FEMA 350—Appendix D,” Structural Engineers Association of California, Sacramento, CA.

Stoakes, C.D., Fahnestock, L.A. “Infl uence of Weak-axis Flexural Yielding on Strong-axis Buckling Strength of Wide Flange Columns,” Proceedings of the Annual Stability Conference, Structural Stability Research Council, April 2012.

Structural Engineers Association of California (SEAOC) Seismology Committee, 2008. SEAOC blue book: Seismic design recommendations, Structural Engineers Association of California, Sacramento, CA.

Thornton, W.A., and Fortney, P. 2012, “Satisfying Inelastic Rotation Requirements for In-plane Critical Axis Brace Buckling for High Seismic Design.” Engineering Journal, AISC, Vol. 49, No. 3, 3rd Quarter.

Tremblay, R. 2001, “Seismic Behavior and Design of Concentrically Braced Steel Frames,” Engineering Journal, AISC, Vol. 38, No. 3, Chicago, IL.

Tremblay, R., Archambault, M.-H., Filiatrault, A. “Seismic Response of Concentrically Braced Steel Frames Made with Rectangular Hollow Bracing Members,” December, 2003, Article 2003. 129:1626–1636, Journal of Structural Engineering, American Society of Civil Engineers.

Tremblay, R., et al. “Seismic Design of Steel Structures in Accordance with CSA-S16-09,” July 25–29, 2010, Paper No. 1768, Proceedings of the 9th US National and 10th Canadian Conference on Earthquake Engineering, Toronto, Ontario, Canada.

Vian, D., and Bruneau, M. 2005. “Steel Plate Shear Walls for Seismic Design and Retrofi t of Building Structures” Technical Report MCEER 05-0010.

Vian, D., Bruneau, M., Tsai, K.C., and Lin, Y.-C. 2009. “Special Perforated Steel Plate Shear Walls with Reduced Beam Section Anchor Beams 1: Experimental Investigation” Journal of Structural Engineering, Vol. 135, No. 3, 211–220.

Wong, Alfred F. “Multi-tier Bracing Panels within a Storey,” Advantage Steel, Canadian Institute of Steel Construction, No. 43, Summer 2012.

Zayas, V., Mahin, S., Popov, E. “Cyclic Inelastic Behavior of Steel Offshore Structures,” August 1980, Report No. UCB/EERC-80/27 to the American Petroleum Institute, Earthquake Engineering Research Center & College of Engineering at University of California, Berkeley.

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2012 IBC SEAOC Structural/Seismic Design Manual, Vol. 4 xix

How to Use This Document

Equation numbers in the right-hand margin refer to the one of the standards (e.g., AISC 341, AISC 358, AISC 360, ASCE 7). The default standard is given in the heading of each section of each example; equation numbers in that section refer to that standard unless another standard is explicitly cited.

Abbreviations used in the “Code Reference” column are

§ – Section T – Table

F – Figure Eq – Equation

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Design Example 1Special Moment Frame

OVERVIEW

Structural steel special moment frames (SMF) are typically comprised of wide-fl ange beams, columns, and beam-column connections. Connections are proportioned and detailed to resist internal forces (fl exural, axial, and shear) that result from imposed displacement as a result of wind or earthquake ground shaking. Inelasticity and energy dissipation are achieved through localized yielding of the beam element outside of the beam-column connection. Special proportioning and detailing of this connection is essential to achieving the desired inelastic behavior.

The anticipated seismic behavior of the SMF system is long-period, high-displacement motion, with well distributed inelastic demand shared by all participating beam-column connections. System yielding mechanisms are generally limited to frame beams with the intent to invoke yielding at the base of frame columns. In many cases, engineers may model a SMF system with pin-based columns as signifi cant stiffness is required to yield the base of large wide-fl ange members. If yielding at the base of the frame is desired to occur within the column section, the column might be extended below grade and tied into a basement wall or a ground-level beam, which is added to create a beam-column connection. Economies of construction usually limit the size of beam and column elements based on imposed displacement/drift limits.

Design regulations for steel SMF are promulgated in a series of standards: ASCE/SEI 7, ANSI/AISC 341, ANSI/AISC 358, and ANSI/AISC 360. AISC 358 provides specifi c regulations related to prequalifi cation of certain SMF connection types that obviate project-specifi c testing required by AISC 341. This design example follows the provisions of AISC 358 for the RBS connection type for the steel SMF seismic-force-resisting system.

The six-story steel offi ce structure depicted in the fi gure above has a lateral-force-resisting system comprising structural steel special moment frames. The typical fl oor framing plan is shown in Figure 1–1. A typical frame elevation is depicted in Figure 1–2. This design example utilizes simplifying assumptions



Design Example 1 � Special Moment Frame

for ease of calculation or computational effi ciency. Because bay sizes vary, the example frames can be designed with different participating bays in each direction, which will result in different sizes of beams and columns for each frame depending on location. This example explores the design of a single frame and a single connection of that frame. Assumptions related to base-of-column rotational restraint (assumed fi xed), applied forces (taken from the base example assumptions), and applied wind force (not considered) are all incorporated into the example in “silent” consideration. Beam and column element sizes were determined using a linear elastic computer model of the building. These element sizes were determined through iteration such that code-required drift limits, element characteristics, and strength requirements were met.

While this example is accurate and appropriate for the design of steel SMF structures, different methodologies for analysis, connection design, and inelastic behavior can be utilized, including the use of proprietary SMF connection design. This example does not explore every possible option, nor is it intended to be integrated with other examples in this document (i.e. Base Plate Design, Passive Energy Dissipation).

OUTLINE


2. Calculation of the Design Base Shear and Load Combinations

3. Vertical and Horizontal Distribution of Load

4. SMF Frame

5. Element and RBS Connection Design

6. Detailing of RBS Connection



• Per Appendix A

� Offi ce occupancy on all fl oors

� Located in San Francisco, CA, at the latitude and longitude given

� Site Class D

� 120 feet × 150 feet in plan with typical fl oor framing shown in Figure 1–1

� Frame beam and column sizes for lines 1 and 5 (Figure 1–2)

� Beam and column sizes will vary from those on lines A and F

� Six-stories as shown in Figure 1–2

• Structural materials

� Wide-fl ange shapes ASTM A992 (Fy = 50 ksi)

� Pates ASTM A572, Grade 50

� Weld electrodes E70X-XX




5 @ 30' – 0'' = 150' – 0''A

5

4

3

2

1

B C D E F

Figure 1–1. Typical fl oor framing plan

AA B C D E F

ROOFTOP OF PARAPET

W21 X 150

W21 X 150

W21 X 150

W21 X 150

W21 X 150

W21 X 150

W30 X 99

W30 X 116

W30 X 132

W30 X 148

W30 X 173

W30 X 191

W30 X 99

W30 X 116

W30 X 132

W30 X 148

W30 X 173

W30 X 191

W30 X 99

W30 X 116

W30 X 132

W30 X 148

W30 X 173

W30 X 191

6th FLR

4th FLR

5th FLR

3rd FLR

2nd FLR

1st FLR

W21 X 150

W21 X 150

W21 X 150

W21 X 150

W21 X 150

W21 X 150

Figure 1–2. Frame elevation – line 1 (line 2 in background)




1.2 FLOOR WEIGHTS

For development of seismic forces per Appendix A:

Table 1–1. Development of seismic forces per Appendix A

Level AssemblyUnit Wt

(psf)Area (ft2)

Weight (kips)

Floor Wt (kips)

Typical fl oorFloor 78 15,220 1187

1315Ext Wall 19 6990 133

RoofRoof 36 15,220 548

656Ext Wall/Parapet 19 5700 108

W = 5(1320 kips) + 656 kips = 7256 kips

2. Calculation of the Design Base Shear and Load Combinations ASCE 7

2.1 CLASSIFY THE STRUCTURAL SYSTEM AND DETERMINE SPECTRAL ACCELERATIONS

Per ASCE 7 Table 12.2–1 for special steel moment frame:

R = 8.0 Ωo = 3 Cd = 5.5

2.2 DESIGN SPECTRAL ACCELERATIONS

The spectral accelerations to be used in design are derived in Appendix A:

SDS = 1.00g SD1 = 0.60g

2.3 DESIGN RESPONSE SPECTRUM

Determine the approximate fundamental building period, Ta, using Section 12.8.2.1:

Ct = 0.028 and x = 0.8 T 12.8–2

T C ha tT C nx =C h × =0 028 72 0 860 8×.028 72 0 sec (see discussion below) Eq 12.8–7

Ta = 0.86 sec

TS

SoD

DS

== =0 2 0 20 60

1 000 1212 0 s12 ec §11.4.5




S ST

TTa DS S

o

+SDS S

⎛

⎝

⎛⎛

⎝⎝

⎞

⎠⎟⎞⎞

⎠⎠= +0 4 0 6 0 4 5 0+4 0 +4 5 For T < To Eq 11.4–5

TS

SSTT D

DS

= = =1 0 60

1 000 60 s60 ec §11.4.5

SS

T TaD= =1 0 60

For T > Ts. Eq 11.4–6

The long-period equation for Sa does not apply here because the long-period transition occurs at 12 sec (from ASCE 7 Figure 22–12).

0

0.2

0.4

0.6

0.8

1

1.2

0 0.5 1 1.5 2

Des

ign

Spec

tralA

ccel

erat

ion,

Sa(g

)

Period (Sec)

To= 0.12 sec

TS = 0.60 sec

Sa= 0.4+5.0T

Sa= 0.60/T

SDS = 1.0gSMF Building PeriodTa= 0.86 sec, Sa= 0.70g

Tmax= 1.20 sec, Sa= 0.50g

Figure 1–3. Design Response Spectrum for the example building

Figure 1–3 depicts the design spectral acceleration determined from T, which is greater than TS, so the design spectral acceleration Sa is 0.70g.

ASCE 7 Section 12.8.2 indicates that the fundamental period of the structure “can be established using the structural properties and deformational characteristics of the resisting elements in a properly substantiated analysis,” which might allow a linear elastic modal analysis to suffi ce. Section 12.8.2, however, limits the period that can be used to calculate spectral acceleration to a value of Tmax = Cu × Ta, where Cu is a factor found in Table 12.8–1. In this case Tmax = 1.4 × 0.86 = 1.20 sec. For preliminary design, the approximate period, Ta, will be used to design the SMF. As SMF designs are heavily dependent on meeting drift requirements, the initial value (usually found to be much lower than the period found through mathematical modeling) will suffi ce for the fi rst design iteration.


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