《AS-NZS-1170.3-2003.pdf》由会员分享,可在线阅读,更多相关《AS-NZS-1170.3-2003.pdf(41页珍藏版)》请在三一文库上搜索。
1、 AS/NZS 1170.3:2003 (Incorporating Amendment No. 1) Australian/New Zealand Standard Structural design actions Part 3: Snow and ice actions AS/NZS 1170.3:2003 Accessed by UNIVERSITY OF SOUTH AUSTRALIA on 29 Jan 2008 AS/NZS 1170.3:2003 This Joint Australian/New Zealand Standard was prepared by Joint T
2、echnical Committee BD-006, General Design Requirements and Loading on Structures. It was approved on behalf of the Council of Standards Australia on 1 November 2002 and on behalf of the Council of Standards New Zealand on 13 December 2002. This Standard was published on 16 January 2003. The followin
3、g are represented on Committee BD-006: Association of Consulting Engineers Australia Australian Building Codes Board Australian Institute of Steel Building Research Association of New Zealand Cement Concrete and Aggregate Australia-Cement Concrete Masonry Association of Australia Limited Engineers A
4、ustralia Housing Industry Association Institution of Professional Engineers New Zealand James Cook University Master Builders Australia New Zealand Heavy Engineering Research Association Property council of Australia Steel Reinforcement Institute of Australia Timber Development Association Universit
5、y of Canterbury New Zealand University of Melbourne University of Newcastle Keeping Standards up-to-date Standards are living documents which reflect progress in science, technology and systems. To maintain their currency, all Standards are periodically reviewed, and new editions are published. Betw
6、een editions, amendments may be issued. Standards may also be withdrawn. It is important that readers assure themselves they are using a current Standard, which should include any amendments which may have been published since the Standard was purchased. Detailed information about joint Australian/N
7、ew Zealand Standards can be found by visiting the Standards Web Shop at .au or Standards New Zealand web site at www.standards.co.nz and looking up the relevant Standard in the on-line catalogue. Alternatively, both organizations publish an annual printed Catalogue with full details of all current S
8、tandards. For more frequent listings or notification of revisions, amendments and withdrawals, Standards Australia and Standards New Zealand offer a number of update options. For information about these services, users should contact their respective national Standards organization. We also welcome
9、suggestions for improvement in our Standards, and especially encourage readers to notify us immediately of any apparent inaccuracies or ambiguities. Please address your comments to the Chief Executive of either Standards Australia or Standards New Zealand at the address shown on the back cover. This
10、 Standard was issued in draft form for comment as DR 05368. Accessed by UNIVERSITY OF SOUTH AUSTRALIA on 29 Jan 2008 AS/NZS 1170.3:2003 (Incorporating Amendment No. 1) Australian/New Zealand Standard Structural design actions Part 3: Snow and ice actions COPYRIGHT Standards Australia/Standards New Z
11、ealand All rights are reserved. No part of this work may be reproduced or copied in any form or by any means, electronic or mechanical, including photocopying, without the written permission of the publisher. Jointly published by Standards Australia, GPO Box 476, Sydney, NSW 2001 and Standards New Z
12、ealand, Private Bag 2439, Wellington 6020 ISBN 0 7337 4914 3 Originated in Australia as AS 1170.31990. Originated in New Zealand as part of NZSS 95 Part IV:1939. Previous New Zealand edition NZS 4203:1992. AS 1170.31990 and NZS 4203:1992 jointly revised, amalgamated and redesignated as AS/NZS 1170.3
13、:2003. Reissued incorporating Amendment No. 1 (April 2007). Accessed by UNIVERSITY OF SOUTH AUSTRALIA on 29 Jan 2008 AS/NZS 1170.3:2003 2 PREFACE This Standard was prepared by the Joint Standards Australia/Standards New Zealand Committee BD-006, General Design Requirements and Loading on Structures,
14、 to supersede AS 1170.31990, Minimum design loads on structures, Part 3: Snow loads and, in part, NZS 4203:1992, Code of Practice for General Structural Design and Design Loadings for Buildings. This Standard incorporates Amendment No. 1 (April 2007). The changes required by the Amendment are indica
15、ted in the text by a marginal bar and amendment number against the clause, note, table, figure or part thereof affected. This Standard is published as a joint Standard and it is intended for use in New Zealand as well as Australia; however, NZS 4203, General structural design and design loadings for
16、 buildings, remains current in New Zealand until the publication of all parts (including Part 4: Earthquake action) and for a transition period afterwards. The objective of this Standard is to provide designers of structures with values for snow and ice actions for use in the limit states design of
17、structures subject to such actions. This Standard is Part 3 of the AS/NZS 1170 series, Structural design actions, which comprises the following parts, each of which has an accompanying Commentary published as a Supplement: AS/NZS 1170.0 Part 0: General principles 1170.1 Part 1: Permanent, imposed an
18、d other actions 1170.2 Part 2: Wind actions 1170.3 Part 3: Snow and ice actions AS 1170.4 Part 4: Earthquake actions NZS 1170.5 Part 5: Earthquake actionsNew Zealand The Commentary to this Standard is AS/NZS 1170.3 Supp 1, Structural design actions Snow and ice actionsCommentary (Supplement to AS/NZ
19、S 1170.3:2003). The Commentary gives background to the Clauses of the Standard. It also gives worked examples and information on issues such as siting of buildings, placing of doors, chimneys and similar and detailing of guttering, valleys, ridges, protrusions and cladding. This Standard is not equi
20、valent to ISO 4355:1998, Bases for design of structures Determination of snow loads on roofs; however, ISO 4355 is drafted only as a guide to preparation of national Standards and the format given in ISO 4355 has been adopted in principle. A number of other Standards were consulted, including ENV 19
21、91-2-3:1995, Basis of design and actions on structures, Part 2.3: Actions on structuresSnow loads. This Standard is not equivalent to ISO 12494:2001, Atmospheric icing of structures. The adoption of this ISO Standard would have involved the collection of data on ice accumulation in Australia or New
22、Zealand, which were not available at the time of publication. Major changes from the previous editions of this Standard include the following: (a) Amalgamation of Australian and New Zealand Standards. (b) ISO 4355 has been adopted, where possible. A1 A1 A1 Accessed by UNIVERSITY OF SOUTH AUSTRALIA o
23、n 29 Jan 2008 3 AS/NZS 1170.3:2003 (c) Incorporating changes resulting from the use of annual probabilities of exceedance (found for Australia in the Building Code of Australia and for New Zealand in AS/NZS 1170.0). (An amendment will accompany the publication of this Standard to change AS/NZS 1170.
24、0, to remove the Appendix E, which provided adjustment of the 1990 edition of AS 1170.3.) (d) Reassessment of snow loads and factors for varying probability of exceedance of load have been included to bring the Standard into accordance with AS/NZS 1170.0. (e) Changing the factor for combinations inv
25、olving snow (given in AS/NZS 1170.0) has been changed to 1.0 from 1.5 and 1.2 (Australia and New Zealand respectively) due to the introduction of annual probability of exceedance (see Clause 5.2). (f) For New Zealand, introduction of alpine and sub-alpine regions. Notes to the text contain informati
26、on and guidance and are not considered to be an integral part of the Standard. AS/NZS 1170.3 is independent of the design requirement specifiedthus becoming a purely technical document. It may be used to calculate snow depths and roof loads given any annual probability of exceedance. The annual prob
27、ability of exceedance (P) defines the snow or ice event (in which pressures and forces occur). Thus a high accumulation of snow with an annual probability of exceedance in the range of 1/200 to 1/2000 is used for ultimate limit states, while a much more frequent event (say of 1/20 or 1/25) might be
28、used for serviceability limit states. In AS/NZS 1170.3, Section 5 gives the ground snow loads factored for selected annual probabilities of exceedance using the probability factor kP and Section 4 sets out the determination of the snow actions (roof loads) that are appropriate for the annual probabi
29、lity specified. The annual probability of exceedance is not defined in AS/NZS 1170.3, but is set out in AS/NZS 1170.0 and by further reference for ultimate limit states in the BCA (Table of annual probabilities of exceedance) and in the Guide to the BCA (examples of structures for importance levels)
30、. AS/NZS 1170.0 gives requirements for New Zealand structures and for Australian structures not covered by the BCA. Guidance for serviceability events and associated limits is given in an informative Appendix of AS/NZS 1170.0 for loads associated with an appropriate annual probability of exceedance
31、(P) for serviceability. A1 Accessed by UNIVERSITY OF SOUTH AUSTRALIA on 29 Jan 2008 AS/NZS 1170.3:2003 4 CONTENTS Page SECTION 1 SCOPE AND GENERAL 1.1 SCOPE 5 1.2 APPLICATION.5 1.3 NORMATIVE DOCUMENTS5 1.4 DETERMINATION OF DESIGN ACTIONS .6 1.5 DEFINITIONS 6 1.6 UNITS.7 1.7 NOTATION 7 SECTION 2 SNOW
32、 REGIONS 2.1 GENERAL 9 2.2 AUSTRALIA.9 2.3 NEW ZEALAND 9 SECTION 3 ICE ACTION 3.1 GENERAL 12 3.2 DETERMINATION OF FORCES. 12 3.3 ICE DENSITY. 12 3.4 ICE THICKNESS 12 SECTION 4 SNOW ACTION 4.1 GENERAL 13 4.2 DESIGN SNOW LOADS 13 SECTION 5 GROUND SNOW LOAD 5.1 GENERAL 16 5.2 PROBABILITY FACTOR. 16 5.3
33、 GROUND SNOW LOADS FOR ALPINE REGIONS. 17 5.4 GROUND SNOW LOADS FOR SUB-ALPINE REGIONS 17 SECTION 6 SHAPE COEFFICIENTS FOR ALPINE REGIONS 6.1 GENERAL 25 6.2 BALANCED SNOW LOAD . 25 6.3 MONO-PITCHED ROOFS 25 6.4 DUO-PITCHED ROOFS. 26 6.5 MULTI-PITCHED ROOFS. 27 6.6 DRIFTING CAUSED BY OBSTRUCTIONS HIG
34、HER THAN THE ROOF 27 6.7 DRIFTING AT PROJECTIONS AND OBSTRUCTIONS 29 6.8 CYLINDRICAL ROOFS. 30 SECTION 7 SHAPE COEFFICIENTS FOR SUB-ALPINE REGIONS 7.1 GENERAL 31 7.2 SHAPE COEFFICIENTS AS FOR ALPINE REGIONS. 31 7.3 OBSTRUCTED ROOFS 31 7.4 DRIFTING ON LOWER ROOFS 32 7.5 CURVED ROOFS. 33 APPENDIX A BI
35、BLIOGRAPHY 34 Accessed by UNIVERSITY OF SOUTH AUSTRALIA on 29 Jan 2008 5 AS/NZS 1170.3:2003 COPYRIGHT STANDARDS AUSTRALIA/STANDARDS NEW ZEALAND Australian/New Zealand Standard Structural design actions Part 3: Snow and ice actions S E C T I O N 1 S C O P E A N D G E N E R A L 1.1 SCOPE This Standard
36、 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. NOTE: In this document, the words this Standard indicate AS/NZS 1170.3, which is regarded as Part 3 of the AS/N
37、ZS 1170 series of Standards (see Preface). 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
38、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
39、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 clim
40、atic changes. 1.2 APPLICATION This Standard shall be read in conjunction with AS/NZS 1170.0. NOTE: Use of methods or information not given in this Standard should be justified by a special study (see AS/NZS 1170.0). 1.3 NORMATIVE DOCUMENTS AS/NZS 1170 Structural design actions 1170.0 Part 0: General
41、 principles 1170.2 Part 2: Wind actions NOTE: Informative documents referred to in this Standard are listed in Appendix A. A1 A1 A1 A1 A1 Accessed by UNIVERSITY OF SOUTH AUSTRALIA on 29 Jan 2008 AS/NZS 1170.3:2003 6 COPYRIGHT 1.4 DETERMINATION OF DESIGN ACTIONS Values of snow actions (Fsn) and ice a
42、ctions (Fice) for use in design shall be appropriate for the type of structure or structural element, its intended use and exposure to snow and ice action. This Clause shall be deemed to be satisfied when snow and ice actions are determined in accordance with the procedures detailed in Sections 3 an
43、d 4, using the values given in this Standard. NOTE: Snow and ice actions may be determined for either ultimate or serviceability purposes. Such values calculated using the applicable annual probability of exceedance (P) would be used in the combinations given in AS/NZS 1170.0 as Su or Ss as appropri
44、ate. Information on serviceability conditions and criteria can be found in AS/NZS 1170.0. 1.5 DEFINITIONS 1.5.1 Alpine Regions where the maximum snow load is usually due to accumulation from a number of successive snowfalls. 1.5.2 Characteristic snow load on the ground (sg) Load at a site with accep
45、ted probability of not being exceeded during some reference period (years). NOTE: In meteorology the term weight of the ground snow cover is also used. 1.5.3 Exposure reduction coefficient (Ce) Coefficient defining the balanced load on a flat horizontal roof of a cold building, as a fraction of the
46、characteristic snow load on the ground. NOTE: The exposure coefficient includes the effect of snow removal from flat roofs by wind. This effect depends on the temperature and the corresponding wind at the site. 1.5.4 Obstructed roof Roof that is not able to shed its snow load through sliding and the
47、 action of wind. NOTE: Parapets, snow fences, steps in roofs, valleys abutting roofs and similar usually prevent snow being shed from a sloping roof, consequently the roof is considered to be obstructed. Obstruction may also be caused by snow that builds up above eaves that are low to the ground. 1.
48、5.5 Roof For the purposes of this Standard, roof means the roof or other elevated surface of the building upon which snow may accumulate. 1.5.6 Shape coefficient (i) Shape coefficient with primary dependence on the geometry of the roof, in particular the roof slope. 1.5.7 Sheltered Sites where the r
49、oof is protected from the wind by obstructions such as other structures, terrain features or numbers of closely spaced trees higher than the roof. 1.5.8 Semi-sheltered Sites where the roof is only partially protected by numbers of scattered obstructions higher than the roof (e.g., scattered trees). 1.5.9 Sub-alpine Regions where the maximum snow load is usually due to a single snowfall. A1 Accessed by UNIVERSITY OF SOUTH AUSTRALIA on 29 Jan 2008 7 AS/NZS 1170.3:2003 COPYRIGHT 1.5.10 Terrain classification A classification based on t
链接地址:https://www.31doc.com/p-3732747.html