AS 1170.4 SUPP 1-1993

1 - AS 1170.4 Supp1-1993 MINIMUM DESIGN LOADS ON STRUCTURES - EARTHQUAKE LOADS-COMMENTARY
4 - PREFACE
4 - ACKNOWLEDGEMENT
5 - CONTENTS
7 - SECTION C1 SCOPE AND GENERAL
7 - C1.1 SCOPE
7 - C1.2 REFERENCED DOCUMENTS
7 - C1.3 DEFINITIONS
7 - C1.6 EARTHQUAKE LOAD COMBINATIONS
8 - SECTION C2 GENERAL REQUIREMENTS
8 - C2.3 ACCELERATION COEFFICIENT
11 - C2.4 SITE FACTOR
11 - C2.5 IMPORTANCE FACTOR
11 - C2.6 EARTHQUAKE DESIGN CATEGORY
11 - C2.7 REQUIREMENTS FOR GENERAL STRUCTURES
11 - C2.7.1 General
12 - C2.7.2 General structures of earthquake Design Category A
12 - C2.7.3 General structures of earthquake Design Category B
12 - C2.7.4 General structures of earthquake Design Category C
12 - C2.7.5 General structures of earthquake Design Category D
12 - C2.7.6 General structures of earthquake Design Category E
13 - C2.8 STRUCTURAL SYSTEMS OF BUILDINGS
15 - C2.9 CONFIGURATION
16 - C2.10 DEFLECTION AND DRIFT LIMITS
17 - SECTION C3 DOMESTIC STRUCTURES
17 - C3.1 GENERAL
17 - C3.2 REQUIREMENTS FOR EARTHQUAKE DESIGN CATEGORIES
17 - C3.3 STRUCTURAL DETAILING REQUIREMENTS FOR DOMESTIC STRUCTURES
17 - C3.4 STATIC ANALYSIS FOR NON-DUCTILE DOMESTIC STRUCTURES OF EARTHQUAKE DESIGN CATEGORY H3
17 - C3.5 NON-STRUCTURAL COMPONENTS
18 - SECTION C4 STRUCTURAL DETAILING REQUIREMENTS FOR GENERAL STRUCTURES
18 - C4.1 GENERAL
18 - C4.2 STRUCTURAL DETAILING REQUIREMENTS FOR STRUCTURES OF EARTHQUAKE DESIGN CATEGORY A
18 - C4.3 STRUCTURAL DETAILING REQUIREMENTS FOR STRUCTURES OF EARTHQUAKE DESIGN CATEGORY B
18 - C4.3.2 Load paths, ties and continuity
18 - C4.3.3 Wall anchorage
18 - C4.4 STRUCTURAL DETAILING REQUIREMENTS FOR STRUCTURES OF EARTHQUAKE DESIGN CATEGORIES C, D AND E
18 - C4.4.2 Ties and continuity
18 - C4.4.6 Footing ties
19 - SECTION C5 REQUIREMENTS FOR NON-STRUCTURAL COMPONENTS
19 - C5.1 GENERAL REQUIREMENTS
19 - C5.1.1 General
19 - C5.1.2 Forces on components
19 - C5.1.3 Interrelationship of components
19 - C5.1.4 Connections and attachments
20 - C5.2 REQUIREMENTS FOR ARCHITECTURAL COMPONENTS
20 - C5.2.1 Forces
20 - C5.2.2 Exterior wall panel attachment
20 - C5.2.3 Component deformation
21 - C5.2.4 Out-of-plane bending
21 - C5.3 REQUIREMENTS FOR MECHANICAL AND ELECTRICAL COMPONENTS
21 - C5.3.1 Forces
21 - C5.3.2 Ducts and piping distribution systems
21 - C5.4 AMPLIFICATION FACTOR
21 - C5.4.1 Attachment amplification factor
22 - C5.4.2 Height amplification factor
23 - SECTION C6 STATIC ANALYSIS
23 - C6.1 GENERAL
23 - C6.2 HORIZONTAL FORCES
23 - C6.2.1 General
23 - C6.2.2 Earthquake base shear
24 - C6.2.3 Earthquake design coefficient
24 - C6.2.4 Structure period
24 - C6.2.5 Gravity load
24 - C6.2.6 Structural response factor
25 - C6.3 VERTICAL DISTRIBUTION OF HORIZONTAL EARTHQUAKE FORCES
25 - C6.4 HORIZONTAL SHEAR DISTRIBUTION
25 - C6.5 TORSIONAL EFFECTS
26 - C6.6 STABILITY EFFECTS
27 - C6.7 DRIFT DETERMINATION AND P-DELTA EFFECTS
27 - C6.8 VERTICAL COMPONENTS OF GROUND MOTION
28 - SECTION C7 DYNAMIC ANALYSIS
28 - C7.1 GENERAL
29 - C7.2 EARTHQUAKE ACTIONS
30 - C7.3 MATHEMATICAL MODEL
32 - C7.4 ANALYSIS PROCEDURES
32 - C7.4.2 Response spectrum analysis
34 - C7.4.3 Time history analysis
36 - APPENDIX CE - STRUCTURAL ALTERATIONS
36 - CE1 INTRODUCTION
36 - CE2 DESIGN
37 - BIBLIOGRAPHY

The commentary provides background material for and guidance to the requirements of AS 1170.4, Earthquake loads.

The Standard considers loads on structures due to earthquake ground motion. The provisions are not intended to prevent damage due to surface rupture, landslip or liquefaction. Nor do they consider other secondary earthquake effects such as fire, loss of services, seiche or tsunami. They do not consider site-structure resonance, where the natural frequency of a site is the same as that of the structure. They do not consider pounding of adjacent structures moving out of phase in an earthquake. These aspects require consideration of issues other than 'loads' and therefore are inappropriate in a loading Standard.

Special structures require special consideration of their response characteristics and environment that is beyond the scope of these provisions. Special structures such as nuclear reactors and cyrogenic tanks, which may present a considerable hazard to the community in the event of their failure, are not covered by the Standard, nor are industrial facilities of high economic importance. In either event, such structures require consideration of strong earthquake motions of very low probability, regardless of location. Structures with unusual structural characteristics, or of novel design or construction, are not excluded by the Standard. However, the Standard may be of little assistance in the design of such structures since a structural response factor (Rf) may not have been assigned.

Bridges are not covered by the Standard but could be included with some additional requirements.

Agricultural buildings may be excluded from earthquake consideration because of the exceptionally low risk to life involved.

Alterations to existing structures are covered by these provisions (see Section 8) but the assessment, strengthening and repairs to existing structures are not covered. However, guidance and some information are included in Appendix E..

First published as part of AS 2121-1979.
Revised and redesignated in part as AS 1170.4 Supplement 1-1993.