Table of Contents
SECTION 1 - SCOPE AND GENERAL
1.3 NORMATIVE DOCUMENTS
1.4 DETERMINATION OF DESIGN ACTIONS
SECTION 2 - SNOW REGIONS
2.3 NEW ZEALAND
SECTION 3 - ICE ACTION
3.2 DETERMINATION OF FORCES
3.3 ICE DENSITY
3.4 ICE THICKNESS
SECTION 4 - SNOW ACTION
4.2 DESIGN SNOW LOADS
SECTION 5 - GROUND SNOW LOAD
5.2 PROBABILITY FACTOR
5.3 GROUND SNOW LOADS FOR ALPINE REGIONS
5.4 GROUND SNOW LOADS FOR SUB-ALPINE REGIONS
SECTION 6 - SHAPE COEFFICIENTS FOR ALPINE REGIONS
6.2 BALANCED SNOW LOAD
6.3 MONO-PITCHED ROOFS
6.4 DUO-PITCHED ROOFS
6.5 MULTI-PITCHED ROOFS
6.6 DRIFTING CAUSED BY OBSTRUCTIONS HIGHER THAN THE ROOF
6.7 DRIFTING AT PROJECTIONS AND OBSTRUCTIONS
6.8 CYLINDRICAL ROOFS
SECTION 7 - SHAPE COEFFICIENTS FOR SUB-ALPINE REGIONS
7.2 SHAPE COEFFICIENTS AS FOR ALPINE REGIONS
7.3 OBSTRUCTED ROOFS
7.4 DRIFTING ON LOWER ROOFS
7.5 CURVED ROOFS
APPENDIX A - BIBLIOGRAPHY
Provides design values of snow and ice actions for use in structural design. It is intended to be used in conjunction with AS/NZS 1170.0, which gives the procedure for structural design. Snow regions are defined and ground snow loads are provided for a range of annual probabilities of exceedance. Other factors cover the environment around the structure, the geometry of the structure and the effect of winds on snow distribution.
This Standard sets out procedures for determining snow actions on roofs and ice actions to be used in the structural design of structures. This Standard is to be read in conjunction with AS/NZS 1170.0.
The principles given in this Standard are generally applicable to all structures. This Standard does not cover the following:
(a) Impact resulting from snow or ice sliding off or falling from a higher roof.
(b) Action that could occur if snow and ice block drainage systems.
(c) Actions resulting from snow and ice on bridges.
(d) The additional wind loads which could result from changes in shape or size of the building structure due to the presence of snow or the accretion of ice.
(e) Sites where snow is present all the year or at altitudes above 1800 m in New Zealand.
(f) Lateral loading on structures due to snow on the ground (e.g. lateral loads exerted by drifts).
(g) Vulnerability of a site to avalanche, avalanche blast and landslide.
(h) Increase in load due to heavy rain falling on snow.
(i) Possible changes to snow loads due to future climatic changes.
This Standard shall be read in conjunction with AS/NZS 1170.0.
First published in Australia as AS 1170.3-1990.
First published in New Zealand as part of NZS 1900:1964.
NZS 1900:1964 revised and redesignated in part as NZS 4203:1976.
Second edition NZS 4203:1984.
Third edition NZS 4203:1992.
AS 1170.3-1990 and NZS 4203:1992 jointly revised, amalgamated and redesignated in part as AS/NZS 1170.3:2003.