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WEB-BASED HANDBOOK (Legacy Edition). CLICK HERE to submit comments.
Because of staff changes and Randolph Langenbach's retirement from FEMA, these handbooks were never published on the FEMA website. These are the only copies available.

FEMA HAZARD MITIGATION
HANDBOOK SERIES

-----HOME PAGE-----

EARTHQUAKE HANDBOOK
________________________________

    Introduction

     Symbols and Keywords

I.       BUILDING STRUCTURES
     A.    Introduction

B. Intro to Seismic Upgrading

C. Structural Concepts

C1. Technical Commentary (1)

C2. Technical Commentary (2)

D. Step 1: Risk Assessment

D1. Upgrade Priority

D2. Geographical Risk

D3. Building Structural Types

D4. Year of Construction

D5. Load-path Assets+Debits

D6. Rapid Visual Survey Sheet
E. Step 2: Mitigation Measures

II. UTILITY SYSTEMS

A. Introduction

B. Utility Mitigation Measures

Appendices
     A.      Regulations
     B.      Glossary
     C.      Acronyms
     D.      References
     E.      List of Contributors

Chapter 1: Buildings

B: AN INTRODUCTION TO STRUCTURAL CONCEPTS IN EARTHQUAKE MITIGATION DESIGN

PART 2: TECHNICAL COMMENTARY, Part 2

THE FOLLOWING IS A DESCRIPTION OF BUILDING DESIGN IRREGULARITIES THAT CAN LEAD TO INCREASED DAMAGE IN EARTHQUAKES

2.4.1.1.1 In-Plane Discontinuity Irregularity: An in-plane discontinuity irregularity shall be considered to exist in any primary element of the lateral-force-resisting system whenever a lateral-force-resisting element is present in one story, but does not continue, or is offset within the plane of the element, in the story immediately below. Figure 2-1 depicts such a condition.

2.4.1.1.2 Out-of-Plane Discontinuity Irregularity: An out-of-plane discontinuity irregularity shall be considered to exist in any primary element of the lateral-force-resisting system when an element in one story is offset out-of-plane relative to that element in an adjacent story, as depicted in Figure 2-2.

2.4.1.1.3 Severe Weak Story Irregularity: A severe weak story irregularity shall be considered to exist in any direction of the building if the ratio of the average shear DCR of any story to that of an adjacent story in the same direction exceeds 125%. For buildings with flexible diaphragms, each line of framing shall be independently evaluated.

2.4.1.1.4 Severe Torsional Strength Irregularity: A severe torsional strength irregularity shall be considered to exist in any story if the diaphragm above the story under consideration is not flexible and, for a given direction, the ratio of the critical element DCRs for primary elements on one side of the center of resistance of a story, to those on the other side of the center of resistance of the story, exceeds 1.5.

Proceed to RISK ASSESSMENT

Figure 2-1 In-Plane Discontinuity in Lateral System

Figure 2-2 Typical Building with Out-of-Plane Offset Irregularity

NOTE: None of the mitigation measures in these Handbooks should be considered ‘pre-approved’ or otherwise automatically eligible for FEMA funding. Only FEMA staff can determine eligibility, once they have determined that an applicant is eligible and they have reviewed a project proposal.

FEMA HAZARD MITIGATION HANDBOOKS Updated: June 13, 2002