ASINZS 1170.2:2011 (incorporating Amarcmont No.1) Australian/New Zealand Standard™ Structural design actions Part 2: Wind actions ee o ‘STANDARDS,“This Standard was published om 30 Maren 2011 ‘The flowing ae represented on Commitee BD-006: ‘Australian Building Codes Board ‘Austalian Stel Insite ‘Ausalsian Wind Fngincering Society Cement Concrete and Aggregates Austalia—Cement {Concrete Masonry Associaton of Austaa {Cyclone Testing Station—Jatnes Cook University Department of Building and Housing. New Zealand Engineers Australia Forest and Wood Produsts Australis owing Industry Association Insttion of Professional Engineers New Zealand Master Builders Acstalin Mossi University [New Zealand Heavy Engiocering Research Association Proper Council of Ausra, Steel Reinforcement Intute of Australia University of Canterbury New Zealand University of Melbourne Adina Interests: ‘Australian Window Assocation “Awstraion Buren of Meteorology Geoscience Australia GGNS Science, New Zealand [National Istute of Water and Atmospheric Research Ltd, NZ ‘Timber Develupenent Assocation University of Auckland, New Zealand University of Sydney University of Tasmania University of Westers Sydaey ‘Keeping Standards up-to-date Standards are living documents which reflect progres im actenee, technology and Sten, To mana th tency all Sundaes te petodcaly review, and snow editions are published. ‘Hetwcen cations, amendmen. tay hosed. ‘Standards may also be wihdeawn. Tt important that readers asufe Themselves they're wing 3 surent Standard, which should elude any arendenete wich ‘ay have been published since the Standard was purchased Dl oration hon una New Zl Sana anh on by % ‘31 www aigabal comau or Standards anus ansundbeking wp ie revantSanad in ‘Zealand web ste st wow. {he on ine esalogve For more frequent tings or notiication of sevisions, amendments and ‘withdrawals, Standards Australia and Standards New Zealand offer a number of ‘date options For inlormation about these serices, wsers should coals! their ‘eapecie national Standards organaton. We ako welcome suggestion for improvement in our Standards, and expecially cncourage Waders to soily ws icwedately of any spyarel “iasceuties. “inbiguiies Please address your comments (othe ‘Chie? Fuceatve. of either ‘Standards Asal or Standady New Zealand the addens hows Om he back his Standard was isu in deaf form for comment ax DR ASINZS 1170.2ASINZS 1170.2:2011 (tcorporting Amendrvent No.1) Australian/New Zealand Standard™ Structural design actions Part 2: Wind actions ‘Ags werner Ho tf hi wrk ray repel acpi in ny omPREFACE, ‘This Standard was prepared by the Joint Standards Austalia/Standards New Zealand (Committe, 80-006, General Design Requirements and Loading on Structures, to supersede [ASINZS 1170,2:2002. Ths Standard incorporates Amendment No. I (September 2012). The changes required by the Amendment are indicted in the text by @ marginal bar and amendment number agalast ‘the elause, woe, table, figure or part thereof ajeced. ‘The objective of this Standard isto provide wind aetions for use inthe design of structures subject to wind action. It provides a detailed procedure for the determination of wind factions on structures, varying from those less sensitive to wind action 1 those for which ‘dynamic response must be taken into consideration, “The objectives ofthis revision are to remove ambiguities, to incorporate recent research and experiences from recent severe wind evens in Australia and New Zealand. ‘This Standard is Part2 of the ASINZS 1170 series Siructural design actions, which comprises the following pars ASINZS 1170, Stuetural design actions Part 0: General principles Part 1: Permanent, imposed and other actions Part2: Wind ections Par 3: Snow and ice [AS 1170, Suuctural design actions an 4: Earthquake actions in Australia. [NZS 1170, Structural design actions Part S: Earthquake actions New Zealand “The wind spesds provided are based on analysis of existing dats. No account has been taken cof any possible future tend in wind speeds due to climatic change. ‘This edition dtfers from the previous edition a Follows: (2) A torsional loading requirement inthe form of an eccentricity of loading is presribed for tall buildings greater than 70-m in height see Clause 2.5.) (©) Adiion of windborne debris impact loading eritera (Cause 25.7). (©) Regional wind speeds Vi, sa, Fone and Vion have been added for rviceability design requirements, and for compatibility with ASINZS 1170.0 (sce lause 3.2). (€)Nominally closed doors, such as roller doors, to be treated as potenti dominant openings ness it is shown thatthe doors and their supports and fixings are capable ot resisting the applied wind loads and the impact of debris (see Clause 5.3.2), (©) Adkition ofa new clause requiring consideration of wind loads on internl walls and ceilings (ee Clause 53. (0) Adjustment of internat pressure coeiciens in Table 5.1(B) for dominant openings on leeward walls, side walls and roof, to more correily reflec the relationship between internal and external pressures when multiple opening evr (@) Clause 5.43 on the combination factor (K.) has been changed to remove some ambiguities and confusion inthe previous edition. An expanded Table $5 gives more examples of the use ofthis factor.(h) Several changes to Table §.6 on local pressure factors have been made, including the Following: (A factor of 15 for small areas on windward walls Gi) A factor 6f3.0 for small areas near the comers of ros Gil) Case SAS (K,~3.0) will, in future, not be required 0 be applied to those buildings greater than 25 m in height with low aspect ratios, (i) Values of maximum structural damping ratios for structures with dynamic response to wind have been made informative rather than normative, [NOTE: Users should seck other sources for advice ow possible values of damping as a Futon of height of building and amplitude of bration G)Annote to Table C3, Appendix C, for shape factors for curved roots has been added to cover the ease of building height to rise greater than () The load distribution specified in Paragraph DS, Appendix D, for cantilevered roofs hasbeen revised to reflect recent research (1) _ Drag coetticients for pentagonal sections have been added to Table E4, Appendix E. (») Drag coefficients for sections of UHE television antennas Types | and 3 in Table E7, ‘Appendix E, have been revised. The value of drag force coefficients for the Type 2 anenna have been removed from the Standard, since this type has not been used in ‘Astras or New Zealand For many’ years. ‘The Joint Committee has considered exhaustive research and testing information from Australian, New Zealand and overseas sources in the preparation of this Standard. The Uesign wind actions prescribed in this Standard are the minimum for the general cases described. ‘The terms ‘normative’ and “informative™ have been used in this Standard 1 define the application of the appendix to which they apply. A "normative” appendi isan integral par ‘oF a Standard, whereas an informative’ appendix is only for information and guidance. Statements expressed in mandatory terms in notes to tables and figures are deemed to be an Integral part of this Standard. ‘Notes tothe text contain information and guidance and are not considered to be an integral pat of the Standard, ‘The Joint Committe is currently considering possible amendments following recent severe wind events, including tropical eyclone Yasi in Australia,CONTENTS SECTION 1 GENERAL, uu 2 a a s & 7 ‘SCOPE, APPLICATION = "NORMATIVE REFERENCES, DETERMINATION OF WIND ACTIONS UNITS. DEFINITIONS. NOTATION... SECTION 2 CALCULATION OF WIND ACTIONS, 2 22 23 24 23 SECTION 3. REGIONAL WIND SPEEDS 31 32 33 3a GENERAL, SITE WIND SPEED. DESIGN WIND SPEED.. DESIGN WIND PRESSURE AND DISTRIBUTED FORCES WIND ACTIONS GENERAL ns REGIONAL WIND SPEEDS (9). WIND DIRECTION MULTIPLIER (i)... FACTORS FOR REGIONS C AND D (Fe, Fin SECTION 4. SITE EXPOSURE MULTIPLIERS. 4 4 a3 44 GENERAL. eS CTERRAINIHEIGHT MULTIPLIER (i). SHIELDING MULTIPLIER (4). ‘TOPOGRAPHIC MULTIPLIER (i SECTION S AERODYNAMIC SHAPE FACTOR st 52 53 54 58 GENERAL. e . EVALUATION OF AERODYNAMIC SHAPE FACTOR... INTERNAL PRESSURE FOR ENCLOSED RECTANGULAR BUILDINGS 00.29 EXTERNAL PRESSURES FOR ENCLOSED RECTANGULAR BUILDINGS FRICTIONAL DRAG FORCES FOR ENCLOSED BUILDINGS wos SECTION 6 DYNAMIC RESPONSE FACTOR 61 62 63 a EVALUATION OF DYNAMIC RESPONSE FACTOR vs ALONG-WIND RESPONSE OF TALL BUILDINGS AND FREESTANDING TOW aoe sd ‘CROSSWIND RESPONSE Sau COMBINATION OF ALONG. WiND AND CROSSWIND RESPONSE ‘0Page APPENDICES ‘A DEFINITIONS... : st B NOTATION... z . 55 © ADDITIONAL PRESSURE COEFFICIENTS FOR ENCLOSED BUILDINGS....61 D__ FREESTANDING WALLS, HOARDINGS AND CANOPIES sss 87 E_ ABRODYNAMIC SHAPE FACTORS FOR EXPOSED STRUCTURAL MEMBERS, FRAMES AND LATTICE TOWERS, Se F__FLAGS-AND CIRCULAR SHAPES vesncowsrnnes G ACCELERATIONS FOR WIND SENSITIVE STRUCTURES. TosSTANDARDS AUSTRALIAISTANOARDS NEW ZEALAND ‘Australian/New Zealand Standard SECTION | GENERAL 4a Scor “This Standard sets out procedures for determining wind speeds and resulting wind aetions to be used in the structural design of structures subjected to wind actions other than those caused by tornadoes. ‘The Standard covers strustres within the following eter: (4) Buildings les than oF equal 0200 high. (6) Structure with roof span less than 100 m. (6) Structures other than offshore structures, bridges and transmission towers NOTES: 1 This Standard isa sand-lone dacaet for srcires within the sore eter It may be ‘sed in general forall stares Bu other iafomatfon ay be nese. 2 Where structures have natural frequencies es than 1H, Seton 6requies dynamic anlsis tobecarsed ou (ee Section 6). 3 In this document, the words tis Standard ndiate AS/NZS 1170.2 whichis regard as 2 ofthe ANINZS 1170 series of Stars (oe Pre) 44 Father adsice should be sought or geometries not described fm this Seanad, such a6 the roofs of pedis below tal Boldin 1.2 APPLICATION “This Standard shall be rea in conjunetion with ASINZS 11700. “This Standard may be used as # means for demonsraing compliance with the requirements of Part BI ofthe Building Code of Australi, [NOTE: Use of mato o nfomavon not given in this Standard should be jst by a special stay (8 ASINZS 1170.0. 1.3 NORMATIVE REFERENCES. ‘The following are the normative documents referenced in this Sandard as. 4040 Methods of esting sheet roof and wall cladding 4040.3. Pant 3: Resistance to wind pressures fr eyclone regions ASINzs 1170. Stractora design actions 11700 Pan 0: General principles ‘Australian Building Codes Board BCA” Building Code of Australia7 Agnzs i022 DETERMINATION OF WIND ACTIONS, Values of wind actions (IV) for use in design shall be established. The values shall be appropriate for the ype of structure or strctural element, its intended use, design working life and exposure to wind action. The following wind actions, determined in accordance with this Standard (using the procedures doiifed in Section 2 and the values given in the remaining Sections), shall be ‘deemed io comply with the requirements ofthis Clause: (2). determined using a regional wind speed appropriate to the annual probability of exccedence (P) specified for ultimate limit states as given in AS/NZS 1170.0, or the Building Cade of Australia (©) 1 determined using & regional wind speed appropriate to the annual probability of cexcsedence forthe serviceability limit states (see Note 3) NoTEs: 1 Information on services Preface). Some design processes require the determination of wind pressure (ultimate or serviceability ‘wind pressre). Such pressures should he calculated for the wind speed asocioted with the ual probability of exceedence (P) appropriate othe limit sate being considered 3 For guidance on Item (b) see ASINZS 1170.0. ‘conditions and criteria can be found in AS/NZS 1170.0 (see 1s UNITS Except where specifically noted, this Standard uses the SI units of kilograms, metres, seconds, pascals, newtons, degrees and hertz (kg, ms, Pa, N, H2). 1.6 DEFINITIONS, Definitions of the terms used inthis Standard are given in Appendix A 1.7 NOTATION “The notations used in Standard are given in Appendix B.sss ntazanny * SECTION 2 CALCULATION OF WIND ACTIONS 2.4 GENERAL ‘The procedure for determining wind actions (MF) on stucures and elements of structures or buildings shall be as follows: (2) Determine site wind spocds (see Clause 2.2) (©) Determine design wind speed from the site wind speeds (ste Clause 2.3). (©) Determine design wind pressures and distributed forces (see Clause 2.4). (8) Caeulate wind ations (ace Chase 25) 22 SITE WIND SPEED. “The site wind speeds (Vas) defined forthe cardinal diretions(f) a the reference height ‘aboveground (se Figure 2.1) shall bes follows: Foan= Ti Ma Mece MM) 22 where Vx = resional gust wind speed, in meses per second, far annu ‘exeeedence of UR, as given in Section 3 probabil M, = wind directional multipliers for the 8 card Section 3 Mca teraiabeight muti M~ shicling nip, as given in Seton 4 M_~ lopograpic Generally, the wind speed is determined a the average roof height (8). In some eases this ‘varies, as giver inthe appropriate sections, according to the structure, Aivections (f) a8 given in tas given in Section 4 ie, as given in Section & 2.3. DESIGN WIND SPEED “The building onhogonal design wind specds (Vn) shall be taken asthe maximum cardinal rection site wind speed (Vaug)lieatly interpolated Between cardinal points within a ‘ssctor24S" tothe orthogonal direction being considered (oe Figures NOTE: That f, Vine esuale tbe maximum value of she wind speed (ag) ithe range [f= 0545] where fi the cardia detion lokwie fom te North ad i te angle the Duiing otogonal axes. tn cases such a5 walls and hoardings and considered, Fi. shall be the maximum value of Fy in sector $22.5" Irom the 45° ‘irestion Being considered. For ulate init states design, Pnshall ot be fess than 30 ms NOTE: A conservative approach ist design te sacar using the wind speed and malipies forthe worst dectn. For example, fora ulding onan escarpment nay bo easly checked hater te FM Wy Md) om he exposed fase (ohare the escape) ee mort ete ‘To shy design, Gls val could then fe sods In design wind oped Sorel dines 22270" FIGURE 2.2. RELATIONSHIP OF WIND DIRECTIONS AND BUILDING ORTHOGONAL, AXES: ° 1 CARDINAL DRECTION. ¢ hea fg th maaan of Fagin ge Bich nec shh he ind FIGURE 2.3. EXAMPLE OF Vy) CONVERSION TO Venue2.4, DESIGN WIND PRESSURE AND DISTRIBUTED FORCES 241. Design wind pressures The design wind pressures (). in pascal, shall he determined for stmctures and pats of structures se follow = (0.5 pas) Wane? Con Cam 240) where P= design wind pressure in pascals oP: Pa where the sign is given by the C, values used to evsluate Cog NOTE: Prssres are taken as posit, indicating remus shove ambit and ogaies, nda pears below bio (Pix = density of sir, which shal be taken as 12 kg/n? building onhogonsl design wind spseds (usually, @=0", 90°, 180° and 270°) a8 given in Clause 2.3 NOTE: Feesome applications, Fay my ea single vue ce may be exgresel | incon height (). eg windward wall tl balings O28m) Cag = aerodynamic shape factor, as given in Sestion 5 Cap. ~ dynamic response factor, os given it Section 6 the value is 1.9 except where the srecture is dynamically wind sensitive (se Sestion 6) 142. Devign frictional drag force per anit area The design wind frictions! drag force per anit aca (f, in pascals, shall be taken for structures and pans of structures 2s follows: T7053 pa) Wana Cox Com +242) 1.8 WIND ACTIONS 281. General Wind actions (My and 17) for wse in AS/NZS 1170.9 shall be dctemnined as given in Chases 25.2 1025.5 snd deflections and seccerations of dynamically windsensitive structures as given Clause 2.3.6, 2.52. Divestions tobe considered Wind sctons shall he derived by considering wind fiom no fewer than four erkogoral Airectons aligned tothe structure, 253. Forces on surfaces or structural elements 2831. Forces derived from wind pressure To determine wind actions, the forces (F) im newtons, on surfaces or structralelterts, sich asa wal or roo, shall be the vector sum of the forces ealeulated from the pressures applicable wo the issue areas (4), 38 flaws: F=E pA) 250) where ‘design wind presure in pascal (norms w the surfice) st height =, callie in ‘clause 24.1 NOTE: The sgn convention for prestues leis to forces towards the surface for positive presses and Yrces aay om the race for negative presires4 reference area, in square mete, at height = upon which the pressure at that Tight ) acts For enclosed buildings, internal pressures shal be ten to at simultaneously with external restues, including the fects of los! pressure factors (K,). NOTE: General, the most severe combinaions of Stertal and eMaral press stall be Seletet for design, ba some reduction im the combined load may Re appleante secon {0 Came $3 ‘Where iti reqited 1p diride the height of tall structure into sectors 10 eslculate witd actions {for example, windward walls of tl buildings [Table 3.2(A)] or for lice towers (Clause E41). the sectors shall he of size to represent reasonably the varition of wied spoed with height, as given in Clause 4.2, 253.2 Force derived fiom frictional drag ‘To determine wind sotions, the forces (F), in newtons, ona tulldng clement, such asa wall, ‘or a Teo salle the vecior sum ofthe fees esleulwed from ditibuted fictional dr steces spplieeble tothe assumed aeas, as follows: FSA 250) ‘design ‘mitonal rag per unit tex parallel to the surface (ealeulsted in ‘Clause 24.2) at height = in pascals Tefeence ates, in square meites, ox which the dsibuted frictions reg stresses (fact 28.33 rorces derived rom force oefctens “Appendices E and F cover strustres for which skape factors ae given in the form of force oefictents rater than pressure coeticens, In these eases, to determine wind stions, the forces (F) in newton, shal be determined 3s fellows: = (0.5 pad Wand Ce Came 230) where Ae ~ scdetined in Paragraph E4, Appendix E, for lattice towers 1b for members sed simple sections in Paregraph E3, Appendix E = ges defted in Appendix F For Nags td circular shapes 2.54 Forces and moments on complete structures “To detcmine wind setions, te ttl resllat forces and everutning momeHts on co structures sll be taken 16 be the suttmation of ie effects of he eXiemal preSutes om succes of the building. Fer restengular enclosed buildings with >707m, torsion shall be applied, based on sn coventiity of 0.26 with respect tothe cente of geome ty of the building onthe along-wind Toedine. he NOTE: For dp >15, the torsional mamas ae primary genratd ty crssind ares and sSpecalistadvice shouldbe sug Fer dynamie effects, the combination of along-wind and crosowind responses stall be caleulated im sccordsnce with Secon 6.25:5 Performance of fatigae-sensitive cements In regions C and D, cladding its connections ard immediate supporting members ard their ‘ixings shall demonstrate perfomance under the presure sequences desired im AS 4040.3 fad the Building Code of Austin, ised on theultimate limit state wind pressure on ‘nteral and intrnal surfaces, a determined in secondance with this Standard 125.6 Deflecions of dynamically wind-ensitive structures Wind actors for dynamically wind-scesitive srucares (an deired in Clase 6.1) whieh may include chimneys, masts snd poles of eitular cross-section, shall be caleulted in fevordance with Sexton 6 NOTE: Infematon on peak scelraton of other wadsersii Anrendie 6. 25.7 Impsct loading from windborne debris ‘Where windhorne debris lading i specified, the debris impact shall be equivalent to— (2) timber member of 4kg mass with a nominal cros-section of 100 mm x50 nm imposing end on at 04 Ya for horizontal wajctories and 0.1 Fe for vetial IMajectories; and (0) spherical tet ball ¥ nr diameter (approximately 2 grams ms) impacting at 04 ¥, fer horizontal trajectories and 03 5 fhe vertical tajectories siractres 6 given in ‘where Fs the regional wind speed given in Clause 32. NOTES, 1 Examples ofthe ae ofthis clause would be the apliation of lame 5.3.2 othe hung, cemdope exosinga ele ron, 12 Thove pct lndinge should be appodtudepeneny in one and IsonSECTION 3 31 GENERAL R GIONAL WIND SPEEDS This Section shall be used to caleulte gust wind speeds sppropriate tothe region in which a structure ist he constructed, including wind direction eles 32, REGIONAL WIND SPEEDS (Fs) ‘Regional wind speeds (F4) forall drcstion based on peak gest wind! dot shall be given in Table 3.1 forthe regions shown in Figure 3.1(A) and Figuie 5.108) where (average recurrence interval) isthe inverse ofthe annus! probabil {er ultimate or servicesbity “The caleulated value of shall he rounded to th nearest I ms yor exceedence ofthe wind speed TABLE 34 REGIONAL WIND SPEEDS Regina ind —- =e een = re Er Ey a Sx Fe Ox Fa a Sox Fe See 2 einre fo 2 ere THe su st Were ra Ey & Be Fe WF 30 se om Texre rr st 38 o Were WF basta | eae [oor oeme* [rae we) [see 1 ales fr Fstare atbee cle he formal or {nfo on ales o antl pcb of eceedence ppp for th ign of races. 33. WIND DIRECTION MULTIPLIER (M.) 33.1. Regions A and W “The wind direction multiplier (M,) forrezions A and W shell eas aiven in Table 3.2.332. Regions B, Cane D “The wind direction mukipier (a) for all directions in regions B, C andD shall be as fallow (2) 0.95 for determining the result forees and overuming moments on complete buildings and wind actions on msjor sructaral elements (©) 0 forall other cases (including cladding snd immediate supporting members) TABLE 32 WIND DIRECTION MULTIPLU (ota) ‘carina | Region egon |] Revlon | Revie Resor eetons | Ar | A |S . 34 FACTORS FOR REGIONS € AND D (Fe, Fo) “The wind speeds given in Table 3.1 for regions C and D include additional factors (Fond To) which sal be as follows: (9) For 8250 yrs, Fe= 105 ond Fe 1 (0) For R<30 yrs, Fe= Fo =. [NOTE: The fctrs in tht Cant have been traced to alow fr atonal ancien inthe {rodiaon of design wind spedn in Regina C and D (topical estone rgions) The wales of {Bove tatom may be vine in the fr following simulation bated om ried eylona rac ‘Soch an analyos would natnraly Schad cyclone stivty tought the northern const of ‘Aastra bein regions Cm D).SNOOIIANM Wik SunolSECTION 4 SITE EXPOSURE MULTIPLIERS 4 GENERAL Tis Section stall De used 0 csleust the exposure multiplies for ste conetons rested 10 terrainheight (Mea) shielding (6) and topography (10), “The design shall ake account of krowr fre changes to tern roughness when assessing terain category and w buillings providing shielding when assessing sickling. 42, TERRAIN/HEIGHT MULTIPLIER (Mi) 42.1. Terrain category definitions “Terai, over which the approach wind flows towards sctuctrs, shall he asserced on the ‘ass ofthe following category deseripions: (2) Category 1—Exposed open terran wit few or no obstructions and water surfaces at ‘srviceaibity wind specds. (©) Category 2—Water surfaces, open tenain, grassland with few, wellscattered ‘batretions having heights generally fom 1.3 19 10 10 (©) Caregory 3 Tersin with mumerous closely paced obstructions 3 m to 5 m high, ‘sich as reas of suburban housing. (8) Caregory 4—rerain with numerous large, high (10 m to 30m high) aed closely spaced obstmictions, such as lage city’ centres and. welhdeveloped industrial complexes. Selection of tormin category shall be made with dus regard 19 the permanence of the obstuctons that constitute the suriace roughness. In pariculst, vegetation in tropical cyclonic egiors shall no be relied upon to msintinsufece roughness during wird events 422 Determination of terrain height multiplier (,..) “The variation with height (2) ofthe effect of terain roughness on wind sped (terrain sad stracurc height multiplier, Maa) shal be tks from the value for flly developed profiles fiver m Tables 4.1(A) ané 4118). For intermediate values of hetaht and terran category, ‘se lines interpolationTABLE: 4.1(4) ‘TERRAINHEIGHT MULTIPLIERS FOR GUST WIND SPEEDS IN FULLY DEVELOPED TERRAINS-SERVICEADILITY LIMIT STATE DESIGN — ALL REGIONS AND ULTIMATE LIMIT STATE— REGIONS A1 T0.A7, WAND B. -reeanincign mater Ca) Bs on ‘Tere ‘Tera Tere . eee | Sees. |e. |e, NOTE: For facrmetnn veers oF igh diode caogor, ee tne nolan TABLE 410 ‘TERRAIN/HEIGHT MULTIPLIERS FOR GUST WIND SPEEDS IN FULLY DEVELOPED TERRAINS— ULTIMATE LIMIT STATE DESIGN REGIONS C AND DONLY aaa Mater a = Tersncaeprin lard? | Terie ageia Sand NOTE Fe Rtreaton oreo nls edteret ener ol 423 Changes in terrain category ‘When considering a ditcction where the wind approaches across ground with changes ia terrain category tat lie within the averaging distances given m Table 4.2(A) for structure eight, the terrain and structure height multiplict (Maa) shall be taken 48 the weighted sverage value over the averaging distnce upwind of the structure at heish level [see Figure 4.112), The Weighted average of aaa shall be weighted by the lengh ofeach tema upwind ofthe structare allowing forthe leg distance st each terrain category change. An example i given in Figure 4.100) 2 abov= sroundFor evaluation at height (2), & change in tesin incorporates @ Isp distance (x) given 8s distance downwind from the stat af a new ferrin roughness to the postion ‘where the developed height ofthe inner leer equals = (Ing distance) Jap ~ larger of the two roughness lengths at « houndary between roughness, as saver in Table 4218). 1£ = reference height onthe srutaresbove the sverage Joel ground level TABLE 4214) AVERAGING DISTANCE FOR STRUCTURE HEIGHT Strucare height Averaging distance apwied of tractre ‘si ‘a! TABLE 4208) ROUGHNESS LENGTHS FOR TERRAIN CATEGORIES Regn eam == Upstignm train category Now tein estegory lal Noten for charges In eral earesory Slee i Taran extaery 9 Fara srteoory ¢ Ut Esorpes of changes i serie caper FIGURE 41 CHANGES IN TERRAIN CATEGORY 43. SHIELDING MULTIPLIER O49 43.1, General Shielding may be provided by upwind buildtgs or other structures Shielding fom wes or ‘vegetation isnot permite inthis Stondard. ‘The shielding multiplier (4) that s appropriate to a parculr direction shall be as given in Teble 43. The shiciding mulinlicr shall he LO where the average upwind ground gradiont is greater than 0.2 or where the eects of sicllng ae not applicable for parce wind rein ora gored which Atcation shall be given to posible combinations of tll buillingsplsced tet Jeadto loca and overall increases in wind scuons8 TABLE 43 [SHIELDING MULTIPLIER (M4) ‘Siding prance | Sing maior ‘or on Only builtings within 4 45° sector of rive 204 (symmetrically poritionsd about the Airsstions being considered) and whose height egress than or exalt = shall be deemed to provide shieleig. 433 Shielding parameter () The shielding parameter (s) in Table 43 shall be determined as follows ae : Tr 434 ‘where |, = svorage spacing of shielding buildings given by: svorage roof height of shielding buildings average breadth of shielding beildings, normal tothe wind sree sverige roof height, abore ground, ofthe secture being shielded umber of upwind shielding buildings within a 45° cector of radius 204 and veh 22 44 TOPOGRAPHIC MULTIPLIER (87) 44.1 General ‘The topographic rulilicr (M4) shall be taken ws fellows (a) For sites in New Zealand and Tastesia over 500m above oes lev: Mo= My Man * 0.00015 5) cotta) we My = hill shape multi: Maz = Nee (effet) mouhiplir ken a8 10, except in New Zealand Ie zones, seeClause 44.3), £ = steclevation shove mean sea level, in meres (b) Elsewhere, the larger value ofthe following: Mh (i) = Ma442. Millshape multiplier (M4) ‘The hill shape mulipticr (XG) shall he assessed for esch cardinal direction considered, ‘aking ino account she most adverse topographic cross-section that scours within the range Of directions within 22.5" on cither se of the cardinal drestion heing cansidereé. The ‘ale shall be ss flows: (@) For 1121) <0003, 84= 1.0 (0) For 0055 #7121.) < 0.45 (sce Figures 42 and 4.3): monty oo) (©) For H(2L.)> 0.4 (see Figure 4.4: (Within the separation zone (see Figure on ii) Elsewhere within the loss topographic zone (sce Figures 42 and 4.3), My stall beas given in Equaion 44(2) 4) vt where 11 ~ ‘bcight of he hil ridge or escarpment 1, = horizontal distance upwind from the ctes ofthe hill, ridge or escarpment 1 § level alfthe height below the crest, |< = horizontal dstenes upwind or downwind of the stricture te the crest of the hill ridge o escarpment t= length scale, to determine the vertical variation of ify 10 be taken as the reser of 0.36 Lor 04 Hf a= length scale, to determine the horizontal veraton of Mj tobe taken ss 4 Ls ipming forall syres, ard downwind for hills and ridges. or 10 Le downwind for escarpments ~ refererccheight on the strectare above the average foal round level NOTE: Figures 42, 43 add ae cross-sections trough the sutures site for a pariular ‘wind irecion For the case where x and = are zsto, the value of Mis given in Table Irrespective of the provisions of this Clause, the influence of any peak may be ignored, Provided it ic sictant fom the ste ofthe structure by more thar 10 times its elevation above fea levelTABLE 44 APE MULTIPLIER AT CREST (FOR GUST WIND SPEEDS) Upwied ee a a es 443 Lee multiplier (M.) ‘The lee (effec) multiplier (..) shall e evslusted for New Zesland sites in the l= zones as shown in Figure 3.1(b)- Forall other stn, the lee muir shall be 1.0. Within the lee ‘zones, the Ie ups stall spply only to wind trom the cardinal directions nominated in Figure 3.106) Esch lee zone shall be 30km in width messued fom the leeward crest ofthe initiating range, downwind in the direction of the wind nominated, The lv 2one compris « 'skadow lee zone’, which ext 12 in downwitd ho the efest ofthe hiting range (Le. 12K downwind ftom the upwitd houndary of the lee zone), and an ‘cuter lee zore" ever the remaining 1? km ‘The lee muliplier shall be 1.35 for sites within the shadow Ive sone (ie, within 12 om of the efet ofthe range). Wihin the outer Ie zon, the Kee multiplier Stal be detemined by linear interpolation with horizontal éitance, from th: shadow outer zone boundary (where Ag. = 1.38} tthe downwind lee ore boundary (where ka = 1.0) ‘NOTE: No le zones have ben enti in AasSECTION 5 AERODYNAMIC SHAPE FACTOR 51 GENERAL “This Section shall be used to calculate the seodyramic shape factor (Cy fr structures or prs of structures. Values of Ce shall be used in determining the presses applied to exch surface. For calculating presses the sign of Cag indicates the diction ofthe pressure on the surfice or cement (See Figure 31), positive values indicat pressure sclng cowards ‘Me surfoce and negative values mdicating pressure acting away’ em the susse (Iss than Ambient pressure, 1. suction). The wind ation effects used for design shall be the Sum Of vihes determined for diffrent pressure effets such as the combination of intemal snd ‘eternal pressure on cnelosed buildings (Clauses 5.3, 54 and 5.5 provide values for enclosed rectangular buildings. For the purposes of this Standard, rectangular buildings include buildings generally made up of recargulsr shapes in pln. Methods for other types of enclosed buildings, exposed members, ktice towers, fe walls, fee roofs and other strstures are given im the. appropriate Appendices, C WF.ice oH acest ras omg ew nal ag FIGURE 5.1 (n par) SIGN CONVENTIONS FOR C,,FIGURE 5 1(in part) SIGN CONVENTIONS FOR O,,5.2. EVALUATION OF AERODYNAMIC SHAPE FACTOR ‘The seroinamic shape factor (Cee) stall be determined for specific surfaces or parts of surfer as flows (2) Enclosed buildings (see this Section Sand Appendte Ci: Ceaz_ = Gye Res fOr intemal presstzes Coxe ~ Cop Be Kea Be Ke for ental prosures Cex = GEKA, for fitional drag foncee (6) Cirealar bins, silos and tauks—see Appendix C. (©) Freesanding wails, hoardings, conapies and roof (see Appendix D) Coy ~ Can Kay Koy fr rss normal 10 sure 21524) Cay ~ Cobo stoma deg forces +530) (@) _Expored siractural members, frames and lattice owers—se Appendix E. (©) Flags andevculer shapes—see Appendix F. ‘extemal pressure coeisient intemal pressure coetiient vstlonal drag fares coettkent ‘et prescure coitisient acting normal to the sufice for canopies, freestanding roofs, walls, andthe fks rea reduction fsctor ‘ombination factor combinatiorfictor applied to exterasl pressures sombinator factor applied to internal pressures local pressure factor porous cling reduction fsctor 53, INTERNAL PRESSURE FOR ENCLOSED RECTANGULAR BUILDINGS 53.1 General Acrodynamic shape actors for itermal pressure (CG) shall be determined. trom Tables 5.1(A) and 5.1(8). Table 511A) shall be used forthe design ease where potenisl ‘operings ate shut ard the wall permeability dominates: Table 5.1(8) stall he used for the sesign cece where openings ere assumed to be open. In all case, he height at which the wind speeds determined shall be the average coo height (hy, a dined in Figure 21. Intemal pressure is fintion ofthe elitive permesbility of the extemal surfaces of the building. The pemesbiliy of a surface shll be calculated by edding areas of opening t> Teakags on that suse of the building (vent, gaps in windows)532 Openings ‘Combinations of openings shall be assumed to give iniemal pressures, which together with extemal presures give the most adverse wind actins. Potential openings inchude doors, ‘windows and vents, Closed doors (inching roller doors) snd windows shell he considered ‘to be openings unles they ae capable of resisting the applied wind pressures i ll regions (Gog impact loading fom wini-tome debris in Regions C and D). This struct assessment shall include clemenis such a8 suppors, frames, jambs, rolet door guides, ‘windlocks and fixings where the resistance of roller doors relies on those. Ths assessment Stall acount for any catenary actions developed and relied upor in the stuctre, {In Regions C and D, internal pressure resulting itm the dominant opering shll be applied, ures the building envelope (windows, doors and cladding at heights up to 25m) ean be shown to be capsble of resisting impact loading Stem windtome debris determined in accordance with Clase 2.57. NOTE: Garage dors designe for Regions C and D according to AS 45051998 canbe ken a5 ending closed and ict une wind forces, and hence seed no be treated a6 damsinant ‘pening however garage doo =v Repons A aed B, shuld beable to revs wind loads according TGASINZS11702, thernse + domira apening should be astmed 53.3. Dominant openings A surfic is considered to sortain dominant qpeuings i the sum of the areas ofall opstings in that suriace exceeds the sum ofthe aeas ofthe operings in each of the otter suraces considered ore ata time. NOTE: A dininant opening dows mot nocd 1 be lange and cam oss 0 4 sesh of a priule ‘popise seni, such a an ofen a vent, weal eer ota epesings ae su ‘S34 Internal wall and ceilings Intemsl walls thst provide an effective seal between spaces within buildings shall be considered as being subjected 10 differential pressures derived fio the interal pressure assessed for thet space, determined in sccordance with Clause 5.3.1 and Tables 5.1(A) and 5.108), wit the worst combination pressure cbeficent of 40.2 eppled tothe other side. “The determination of pressures within a spice shall acount for known and likely openings derived in czordance with Classe 5.32. Tr Regions C and D, likely openitgs shall mchude Iallures of the bullding envelope anes specifi debris impact resistance measures te crployed in ccondanee with Cltses 2.5.7 3.3.2 NOTES: 1 Certngs may aso be subjected sguican winded pesanes, depending om cies ‘ch 3 the WO" permeabiiy, pronny 1 cass Wah pea! Soman openings nd Ne Ibeatin of maven 2 In those cases where internal sls and ceilings do ot form permanent seal then ‘tart prossres rived wings no prosore coaTcent of 48 Sy be apeopit 5. Diteatsl pressures on ileal alls a cetings may be ried bY prvi Of spproprate venting.TABLE 811A) INTERNAL PRESSURE COEFFICIENTS (C2) FOR BUILDINGS WITH OPEN INTERIOR PLAN~ CASES FOR PERMEADLE WALLS WITHOUT DOMINANT OPENINGS (9) Windus wll ipemmee 03 (Windward val imperil 43 TABLE 5100) INTERNAL PRESSURE COEFFICIENTS (C,.) FOR BUILDINGS WITH OPEN INTERIOR PLAN— DOMINANT OPENINGS ON ONE SURFACE. =o54. EXTERNAL PRE S41. Extermal press /NCLOSED RECTANGULAR BUILDINGS.Fer leeward walls sie walls and roofs wind speed shall he tnhen asthe value reference height (i) shall be taken asthe average beih of the root Where two values of Gu te listed, roofs shll be designed for both values. In these cases, roof surluces may be sibjested to either value dus so turbulence, Akernative combinstion= ‘of external and intemal pressures (4 also Clause 3.3) stall be eonsidcred, wo obtain the ‘os severe conditions for design. Fer roof, the following sKcrnaive load caves shall he considered (0) Wher using Teble 5.3(A), for he appropriate root type slope and edge distnse apply the more negative value of Cpe to all pressure zones and surfaces: and (Gi) apply theless negative (or most postive) value of Gy to all pressure zones snd Sitcss. (b) When using both Tables 3.3(8) né 5.3(C), and forte appropriate parameters— ()spply the more negative value of Cpe ftom Table 3.3(B) te the upwind slope ‘egether withthe value from Table 3°(C) 0 the downvem slope; std Gi) spply the tess negative (or positive) value of Cpa from Table 54B) to the "uptsnd slope togetferwitk the value rom Tab: 5 5(C) 1 the downwind slope. (©) When using Table 3.3) only, for stesper crossing slopes on hip roof, apply the appropriate Cy, value tbat slopes. Fer the underside of elevated buildings, Cy stall be taken a5 0.8 and -0.6, For buildings with less levation store ground than oft-third of the height use linear interpolation between these vahies and 0.0, according to the rato of clesr walled height underneath fist floor level to the toiel building height. For the esleuliton of underside extemal ressures, wind speed shall be taken as the value at # forall Underesves pressures shall he taken a= equal fo those applied tothe adjacent wall eurfice ‘below the surtace under consideration. TABLE 524) WALLS—ENTERNAL PRESSURE COEFFICENTS (G.) FOR [RECTANGULAR ENCLOSED BUILDINGS—WINDWARD WALL (W) eres prewere weit 0 (ve ped vase wo ne ‘Os when ed var ei 02 when wed ed fier Be For cleat bing — ‘Os wna ken)TADLE 521) WALLS EXTERNAL PRESSURE COEFFICIENTS (Ga) FOR RECTANGULAR ENCLOSED BUILDINGS LEEWARD WALL (L) Rot tone echeen | Someta roe ” : 8 weeny | Ate = TABLE 52(C) WALLS EXTERNAL PRESSURE COFFFICENTS (C,,) FOR RECTANGULAR ENCLOSED BUILDINGS—SIDE WALLS) inal ares rom wierd oe prevnre corte (Ga TABLE S3(A) ROOFS _EXTERNAL PRESSURE COEFFICIENTS (G,) FOR RECTANGULAR ENCLOSED BUILDINGS —FOK UPWIND SLOTE (U), AND OWNWWIND SLOPE (D) AND (K) FOR GABLE ROOFS, FOR a= 10° eo pean treat praesent Ga) ‘crowwiea supe [upwind spe | from vndwart eae | aus suas Yerieroce | ‘Doemwin ope steee ee | das ‘Sul be cari om on value te ames 2 Te aly er sees ar pol fr elaineTABLE 5308) ROOFS—EXTERNAL PRESSURE COEFFICIENTS (C,.) FOR RECTANGULAR ENCLOSED DUILDINGSUPWIND SLOPE (0) a 10° Tiere premere semana et pth degree ne Note) pring | eaio mt sbpesit) | ee Sos E10 |13.-06|=12.-05 07-07 [25.00 [03.02 [02.03 NOTE For temas ale cpa slopes a hl ay, tar eps Hal be wad N TABLE 5:3€) ROOFS —ENTERNAL PRESSURE COEFFICIENTS (C,,) FOR RECTANGULAR [ENCLOSED BUILDINGS—DOWNWIND SLOPE (D), AND (K) FOR HIP ROOFS, FOR a210° pared Reng dees ee Note we fos | zs ae | azte [7 0s [aos [as [oe | rorscneect:-nas7 a S42 Area reduction factor (K) for roofs and side walls For rofs and sidewalls the ace reduction fctr (A) sll he as given it Table $4. For all caer cases, Ay shall be Taken a5 1.0. Tributary ares (4) he area conning othe force being considered, TABLE 54 AREA REDUCTION FACTOR (A,) Tabata wee a ort ‘Aes venti fester) LE Remscne aa oT a eR a ‘S43. Action combination fer (kK) ‘Were wind pressures acing on a combinstion of surfaces ofan enclosed balding (e3. windward wall. oo side wall, leeward wall, intemal surface) contribute siruancotsly 10 {2 sractral ction effect (eg. member axial fore or bending moment) on © svstial Semen, combination ews (Kes snd Kes), SS that LO, hs) be spplied Wo te extertal and interal surcaces when. caleulatng the combined forces.A surface shall be cither 2 windward wall,» side wall « Jeewerd walla roof (ihe upwind ‘nd downwind hotell be treated together as «single surface), ofthe intemal surfzcer of the building weated as single surface. AN Interral surface Shall not be weated a tTective surface if Ge 02, Where pressures on two contnibuting sureces act together in combination to produce & ssructural action effet. Ke» and Kez may be taken a6 0.9. Whete three (or mote) ‘ontribating sariaces actin combinstion, Kay and Kesmoay he taken «5 0 [Exemples of appropriate combination factors (ux and Ks) are given in Table 55 For any oo and side wall, the product K. Kz shall wo be less than 0.8 [NOTE: Aion combiraion ficion leas dn 1.0 account fr he ne sinulineoes ation of peak rssure en tleve stan TABLE 55 EXAMPLES OF ACTION COMBINATION FACTORS K.. AND K.:FOR ACTION EFFECTS ON STRUCTURAL ELEMENTS FROM WIND PRESSURE ON TERTECTIVE SURFACES eee nae Pel en ——— Waas oy os 11 oe (© sereone mrs 1 7 oT Pree foe ——~ = ato ot ema vernal pracsure ——|. eo ——- fo fe a)TABLE 55. (cowed) = ee ae cae Ae my ee SA Local pressure factor (Ki) for lading “The local pressure factor (K,) shall he taken as 1.0 in all eases except wien deter wing foes applied to clsdiing, thir fixings the members that dreety sapport the claddirg, and the immediate fixings of these memters, In these cases shall be taken cither a8 1.0 or the valu from Table 5.6 for the arca and locations indicted, whichever je the most adverse effect when combined with the external and intemal presses ‘Where more than on ease applies, the Iargeat value of Ky om Table 5.6 shall be wed. Where the cladding or the sapponting member extends beyond the zone a given in “Table 5.6 2 vac of Ke ~ LO shall apply to wind force contributions imposed from beyond that zone” ‘The value of dimension is the minimum of 28 oF O.2d or the height () as showe in Figues3, ‘Where interaction is possible, external presses shall be taken to act simultaneously with jncmal pressures given in Clatse 55 and with the uader-caves prewures issn it (Clause 34.1, and the resultant forces shall te added, Design cases for negative pressures “Table 8.6 re aliemative cases and shall not be applied simulsneousls For rectangular buildings, the negative limit on the product K, Coe sll be 3.0 mal cases, ‘The RCI case only applies to Mat or nest-‘It roo (sie less than 10°). Fr fat or nea-t roofs (slope less than 10°) with parapets, values of K; for areas RAT, RA2 and RCI in the ee ofthe parspet may be modified by muhiplying the values from, “Table 5.6 bythe parspetrdution factor (K.), given in Table 57.LOCAL PRESSURE FACTOR (Ki) Tae as Deseneme | eee 30 | restr meter |e ‘Wr at war | oan | score | awsiee | ts Seane pear rmadommet, | mci | an | asozu | -emmocan | 30 Uri ee are Ba | ae | tise 05s Er saimissrmets | Rat | an | asaine <3 » “ Se soe athe ao Th ong pst (9) Sid tee) Sie yh om bard REDUCTION FACTOR (&,) DUE TO PARAPETS I ig of perp hore seme 1 Settee fees octalFIGURE 58. LOCAL PRESSURE FACTORS (f,)S45 Permeable cladding reduction factor (K,) for roefs and side walls ‘The pemsable cladding reduction factor (Ke) shall be taken a5 1.0 except that where an exteral surface consists of permeable clading and the solidiy rato is less than 0.999 and ‘xeceds 099, the values given in Table 58 may be used for negative pressre. The rolidity Tato of the surfoce isthe ratio of solid arca Wo toa ares f the sures. Figure 4 shows ‘amension a TABLE 58 PERMEABLE CLADDING REDUCTION FACTOR (Ky vinta dance rom windward lar tee Nae oe aA > FIGURE 5.4 NOTATION FOR PERMEABLE SURFACES, 85. FRICHONAL DRAG FORCES FOR ENCLOSED BUILDINGS “Te frictional drag (shall be caculsted for roofs and sie walls of cxclored bangs in ation to pressres normal tothe surface, only whete the ratio dt od s greater than 4 The serodynamic shape factor (Ce) calsls the frictional drag coefficient (C2) in the rection ofthe wird as given in Table 58 “The eifect shall he calculated on the basis of areas a follows: (2) Forts, atea=(O°20K4m). (er 2ixaea. (0) Forh> harFRICTIONAL DRAG COEFFICIENT (G) FOR dit or dod ‘sinnedSECTION 6 DYNAMIC RESPONSE FACTOR 61, EVALUATION OF DYNAMIC RESPONSE FACTOR ‘The dynamic response factor (Cy) shall be determined for sircturs or elements of siructres with mterlfrstmodefundameaalfequencies as follows: (2) Groster than 1 Hs Coa 10. (8) Less than [Hz for tll buildings and freestanding towers— A) ess than 0.2 Hz isnot covered by this Standard; (8) Verween 1 Htzsnd 02 114 Cap sl be a8 defaed in Case 62 for along wind resporse and Clause 6.3 for crsswid response: (©) where the frequencies of vibration for the Wo fundamental modes of ‘way ae within 10% of exch ether and sre both less than 0.4, this s not covered by this Standard; i) for cantilever rooks— JA) less than 0.5 Iz ist covered by this Standard; (B) between L Hz and 0.5 Ha, Coq Shall be 5 defined in Persgraph DS, Appendix D. ores: 1 Appendix G provides infration on calsltng accelerations for services in ll wind. 2 Fer aaual trequences les than 02 Ha, tei greater than 200m, or wharoversiatcant ‘coupling is evident inthe Fest thre tdes of ibeion, wind iusel testo shoud be ‘adr, 3. Dynan reapome itor fr roa sapporta on te oF more sides with rar eyuecion lets an 1 Hz re net provided mths Sundae. Spec tas such as Wendel eg, shouldbe wnderaken, 62 ALONG-WIND RESPONSE OF TALL BUILDINGS AND FREESTANDING TOWERS 621 General “The dynamie responce factor shall be as given in Clause 62.2. [NOTE: Intention on peak song. indacolricn For serviceability i given in Appenia G. 622 Dynamic reponse factor (Ci) Tor calculation of sction fests bending moments, shear farce, member forces) at 3 hight son the structure (see Figure 6.1), the wind pressures oF the siuctue as height stall be multiplied by a dynamic response facto (Cyn). This fator is dependent on bath = aad sand «72h, For the calculation of hace heading moments, deflections and acecleration atthe top of the strut, a single value Of Cg stall be used with ¥ taken 35 2:10, Fr the calculation of Cay the Vile Of Fin is saleulsted tthe reference height (H).Level at which action effects are boing caloulatea FIGURE 6.1 NOTATION FOR HEIGHTS Te éyramie response flor (4a) sal be ceeulse 2s follows: a, fate eS alk a (aah) ‘eight ofthe level at which action effects are calculated fora structure ‘average root beight ofa structure above the ground, or height to the top of 3 ‘terbulence intensity, obisned tom Table 6.1 by setting =~ ‘peak fter for the upwind velocity uctustions, which sal be taker 383.7 ‘eckeround factor, which is @ measure of the slowly varying bickgrownd ‘componet of te Muctualirg response, cause by Tow-flequeney wind speed ‘anations, given as follows: a - = ya Lezilinsf v0! 620) rs where has the average bruh ofthe structure between heights sand 1g. = smessure ofthe iniegral turbulence length scale at height in metres sai 620) 1, ~ height factor forthe resonant response which equals = (4)? ‘ge ~ pesk factor for resonant response (10 min period give by 0g, {600r,) 020) = sige reduction fst given s follows, wheter is fst mode natural frequency (of vibration ofa sructute inthe slong-wind ditecton in Hertz atd has the [sverage breadth of the structure between heights O ad | ESE 649)4, ~ (24) times the spectrum of turbulence inthe approsching wind seen, ‘sfallows ay temsvi)% whew N= retced teaerey (non mensional) ~ all + Bf) Pan = fist_mode nsturnl frequency of vibration of ‘Sucre the along-wine ection here. Vine ~ billing design wind speed determined et the bing height, (Se Clause 23) ato of structural damping 19 ential damping ofa stuctre 626) | Forszacral amp forall ts mconmende mam ae of ar ll epee conic nrc 003 0 2 rarercaral camping esos ae ommended mane aes fe Stenson sop ofa eigenen Tenirced comers nce DO'S af eal for elton eakltns; 91 of ee fr ‘itdaion af mcteaions ty ef wl uiings an ver 5 Wis seu sek oer ures ave on posible as OF sural dangling as abo oe ‘ape afcontctin, ting Smenson od opi aonTADLE 61 “TURBULENCE INTENSITY (1) Eaton regs ond tae ote Serenity it tates ‘iegon | “irom Terrain ater Regan SW and Terra category 2, Aegiore Wand "NOTE For rnin tales of Bh =] ard rain xapy Theor telaion alle 63. CROSSWIND RESPONSE 6341 General (Clause 632 gives methods for determining equivalent stati forces and bese overturning moments and Coy Can for tall encloed buildings and towers of rectangular cross section, and Clause 6.3." gives deflections and equialert stati forces fer chimneys, masts std poles of eitculr cross-section. Calculation of crosswitd response isnot reqited for poro=s Tati tower. 1 formation on peak eotevid acelerton fr serviceability i given in Appendix 2 UNF satemas ofthe cscs shown ia Figure ES, Appendic E, may have significant ential or costing response 6321. Equlvalen sue crosswind force ‘The equivalent static crosswind force per using fore equals nas ines aeceleraon) Pie Want Ae where Fis is evsluted at 2~ h, and dis the horizontal depth ofthe structure parallel othe ‘sind ream and2 2) bc teal) 14 2830) ie a= ne sup consto ft for cesvnd celeron, hen by: > ove 0248 stew = mode sap rove oust fore dal ode, Va of ects aensn 1.5 fore uniform cantilever (0.5 for lender framed structure (moment resisting) ~ 10 for s building with central core and momentesising facade 23 for s tower decreasing in stiTness with Neigh, or with large ase at the tp ‘ahi obtained stom fing &(2)= (G/F to the computed mods shape of the stretare (2) = fist mode shape as a function of helght =, nomlized to sntyat 2A Ce = crosswind farce spectrum coetisket generalized fora linear mode shape fiver inClause 63.23 632.2 Crosswind base overturning moment “The crsswind base overtuming moment (8). (which can be derived by the integration oa 619 of mf) 3 shal es flows: ose SeablntE (3, 1430) eek wie te wake (<2) ie he mae pe creton ir fr eosin ta vei ne 315 Cone crn cute is “The reduced velocity (J) shall be ceoulted es follows using Vays saluted {allows -—Yine _ lt gta) ‘alter ofthe crossuind force spectrum cocicient generalized fora lines mode share (Ca) sll fe eaoulsted fom te YedecedvelOcRy (¥q) a8 HIN (see FIgUtes 0210 0.3) (9) Fors 3:11 square section (bd), where Vis inthe mange 21916 (i) For rtutene intensity of 0.12 a1 203 6x6) lege Ce ~0ODI353,* 00134," s0187,* 0348, (ti) For urtutence intensity of 02 a 20/5: es Ce 006365) 0.000081,* —c0028y,? + 001991,7 +013, 2985 ...610)©) Fors 6l:t square section (hil), whore Yasin the range 31016: (8) Forturbatenc tensity of 0.12 at 23 Vos Ce (Gi) For urbutence tensity of 0.2 82015: lo Ce =0.000534"," 0.01251, +0141, 0384, 236 6.308) (©) For 6:2:1 rectangular section (ha), where Vis inthe range to 18 (0) For turbulence intensity of 0.12 at 203 conser, -0016sr + 020178 -0897,-276 ...6307) 32. 006s3v,* _ovosow,* 1-002 +0.000123"." You C= 630) (Gi) For turbulence intensity of 0.2 8 215 5+ 006578,5 0.000571," 1-002," +0:000124F." to C= 63410) (@ Fora 61:2 rectangular section (ha). where Vis inthe range to 16: (0) Forturbulence itensity of 0.12 at 29 osu Ce 0.0004570,2 -042267,5 +0596, 4055 63411) (Gi) Forturbutence intensity of 0.2 8 25 tou Ce =0.000887," —0.0197F,7 +0.365F, — 3.82 63412) NOTE: For inset values of ih bd stl be we, Thebonue FIGURE 6.2 CROSSWIND FORCE SPECTRUM COEFFICIENT FORAS:11 SQUARE SECTION$s | ~-tabaence 3s “ "SQUARE SECTION REDUCED VELOCITY RECTANGULAR SECTIONoe tea) FIGURE 65 CROSSWIND FORCE SPECTRUM COEFFICIENT FOR A612 RECTANGULAR SECTION 633 Crosswind expense of chimneys, masts and pole of circular erosmsection 833.1 Coasswind np detection The meximem amplitude of tip deflection (jax) in erocawind vibration athe erie wind speed duc te vorizt shedding fbr chironeys. muds er poles of circu cross-section (without Tners, sakes or other appendages rea he tp) shall Ke calceated fellows: yon = KOUSE 9303) re 1 = fer fx mast tp delete, ha 50.50 fr kel rosso 1, = serge esha the tp tind of the stuctre $0~ Senson neersven by: arm Eloat) sm. = averige mas fr ant Pht ve the fp tind he suse {= roof recur damping ttl damping of scare 69.92 Byaiaen satic cesta fore The equivaleat static wind force per unit height (wn) for chimneys. masts or poles of siccular cose ction (without Taddery stakes or ther appoedages neat He Wop) = fit a height se) shall Re clculated we elon al) ~ m2) 2 OF Yam $2) 9304) where ‘m(2) ~ sce perunit height ae «funtion of height @) ‘my > fist mode nual tequeney of vibration of s structure, i ent {Ale) = fits made shape as a function of height (2), nomalized 10 ity at ‘which sal be taken as (AFNOTE: Eguation 63(14) maybe etn a "05 Pa Chao whee Fa, ert wind pte or orn shedding, whish i approninatly e Sn xb. torerus sectons cagxcg, = Prout of setive aerodyanie shape ator and dyna espns ete 64. COMBINATION OF ALONG-WIND AND CROSSWIND RESPONSE The total combines peak scalar éynamie setion ctfect (&), such 48 an axa Toad in 3 ofan hall teas follows: = eNom Cl #2601 ‘45 = scton eect derived fom the peak slong-wind response ap ~ scton cleo rived ftom the peak eressmind response NOTE: 1 The fsior [Gg (t+ 2g a gus tr (6) 22 Masi acon effets derived tm the croton sepa of chinmey, mas and ples of sear ersssvtion (Clause 6-3). which ges a he eel wind speed Ot eter stdding should net be coahinod with ion fect hr slng.wind respee Calolae ats ditteent wind spend[APPENDIX A. DEFINITIONS (Nomative) For the purposes of this Standard the definitions given herein apply. AL Aerodynamic sape fastor Factor 1 sesoant forthe effets of the geomeny of the structure on serface pressure dee 10 wind. Az Annual probability of exceedence of te action “The probability het «value wil he exceoded in ony one Jeet. NOTE: This is te inverse of the sealed “ren period! beter descibed as the average ‘etrance interval AB Aspect ratio ato of the average roo! height ofa building to the smalls horzortal dimension, othe "ratio of he largest dimension of stuctaral member ots erosswind breadth, Ad awning Roof structure, asually of limited extent, projecting roma wall of building. AS Canopy Roof ascent o or sched to «building, generally tot enclosed by walls. Ab Chiaaing ‘Material that fora the external surface ver the taming of building or srwewt AT Design wind speed speed for use in design, sdjusted for anmial probability of exceedence, wind iccton, geographic postion, sureurding environment end eight A Dominant opening Opening in the external surface of an enclosed beilding, which directly influences the average intemal pressure in respoase to extemal pressures at thet particular opening OTE: Dominant ofeings need note large. AS Downdraft \Verical ir motion originting in ¢ thunderstorm, suing in severe horizontal winds at aground level. AO Dea Force ating in the direction of he wind steam; see eso lit, ALT Dyramic response fcior Factor 10 account forthe eects of Pustuating forces and resonant response on wind- sensitive ractues,AZ Eecemrtey ‘The distance ftom the eenirid of a serfae, tothe point of application ofthe reveltant free erived from the net wind pressure AIS. Effective surface ‘A wall, rof or intemal surfice of « building that contributes significantly to load effects on ‘major snuctural elements AIS Elevated building ‘Building with s clear, anwslled space underteah the firs floor level with height from ‘around fo underside othe fits oor of one-third or more ofthe total height ofthe huildng AIS. tnetosee putaing Building that has rof a fll perimeter walls (nominally sealed) frm floor to roof eve. AIG Escarpment ‘Two-dimersional, steeply sloping, fice between nominally level lower and upper plsins swiere the plsins have average slopes of nat greater than 5%. AIT First mode shape Stape of astrustere ats maximum amplitude wade fist ode natural vibration. [AIR First made natural fresitency Frequency of fee oscillation comesponding 10 the Towest karmonie of vibration of 3 Al9 Force coefficient Cociticlent tht, wen multiplied ty the meidert wind pressure and a reference ste gves the fore ita spesitie director, A20 Free roof Roof (of any type) with no enclosing walls wndemeath eg. feestnding capon). ALL Freestanding walls, ‘Walls that ate exposed ithe wind on Doth sis, with no ror tached (eg. fences) A22 Frictional drag ‘Wind force ner unit tea acting ins direction paral! to the surface in question. AIS. Gable root [idged root with two sloping surfaces and vertical angular end walls Ans Isolated thrce-dimensionsl topographic feature standixg above the surounding pi Insving slopes <5ALS Hip root ‘Ae wih tesa ed) hrs, pr news nwt vel evel und, 4 hip roof on a rctargulsr plan has two triangular sloping toot atthe shot sides (tip snes ne wo tepcztéal oping roots he lens ses. A26 Hoarding Freesatdng (rectangular) signboard, andthe Tk, supported cee ofthe groend. A27 Immediate supports (cladding) ‘Those supporting members to which cling i directly fced (eg, battens, perins, git, studs) ARN Lay aistance Horizotal distance downing, requited forthe etfs ofa change fn train roughness en ‘wind speed o reach the height being investigated. ADS Lattice towers Three-dimeasional tlaneworks comprising thrse or more linear boundity members intercomnecied by linear bracing members joined at common points (nodes), ealosing ‘open atea tough which the wied tay pass ase Lif Fore acting st 90° othe wind steams soe also drag, ABI Mancard real A roof with two slopes onal four sides, the lower slope steeper thar the upper slope NOTE: A mansaed oof with te upper lps estan 10° may he sium be Ha tpl A32_ Monostope root Planar roo with a corstatsops and without» rds, 833. Obstruction [Natural or man-made objects that generate turbulent wind flow, ranging from single tees 19 forests and Tom isolsted small structures to closely spaced muit-storey buildings. AM Rermesbie Surface with an sgeregition of smal openings cracks, and the Hike, which allows alr 19 passthrough ander he sction af a pressure iffreti ABS Pitched root [Bi-fold,b-psnar reo! (wo sloping surfaces) meeting ata ridge, 36 ressate ‘lr pessere referenced 1o bien st pressure ‘NOTE: tn this Sandrd, sogativ vine are le than embio (ution), postive vues exsed ‘anbicnt Nel premares arma oa artic Ce dco peed.ABT Procure coefficient Ratio ofthe pressure astng at the point on «surfics tothe fee sream dynamic pressure of the incident wind ABE Rectangular building Tor the purposes of Section 5 of tis Standard, rectangular buildings insade buildings setcrelly made wp of restangular shapes in plan. A30_ Reynolds number “The rato ofthe neta forces to the viscous forces he srflow: 540 Ridge (topographic feature) Two-dimensional eres or chain of hills With sloping faces on ether side oF the eres. ‘AAT Roughness length “Theorticsl quantification ofthe teyblence inducing nature of « particular type of termin on aii (ina. AAD Scruton nember ‘A mass damping parameter, (AAD Stelter room Any space desigrated 1 provide sheer to one oF mote Perot AE Sotiity (of eladating) Ratio ofthe solid are to the total area ofthe setae dS. Stractaral cements, major Suustera eements wit wibuary areas ate greater than 10 m2 ‘Ado Structural elements, minor Structoal elements with wibutary ares are lessthan or equsl to 102, AAT Terrain Surface roughness condition when coesidcrng the siz aed arrangement of citations © the wind AS Toposraphy Major tnd surice features, comprising hill, valleys and pains, that srongly intucase window pater A Tornado. ‘Viotcutly rotating colon of ait that is suspended, cbvervable as. fumnt cloud stacked to the cou hese af a convective coud ASO Tributary area Arcs of building srlice contibutng to te force being consideredASL Tropical eyelone {An intense low-prosur centre sccompaied hy heavy ruin ad galefores winds o greater, 11 forms over warm topical ocears and decays rapidly oer laud. Such spstems sect 2 large ares and inthe southern heraiaphere, winds spiel clockwise into the ceate AS2 Troughed root I-fOt, Diplans oot with valley atts lowest point ASS Turoutence intensity The rato ofthe standard deviation ofthe uststing component of wind speed to the mean (ie svergged) wind speedAPPENDIX: B NOTATION (Somative) Unless stated otherwise, the notation used in this Standard chall have the following ‘meanings with respect to suctre, member of condition 10 which clase sapped ‘NOTE: See Case 1S forums, 4 surface aes of the element orth tributary ates that transmits wind feres io the “lement. being ra upon which the pressure ast, which may not always be poral Yo the wind Stare when sed in eorjenston with the pressure cooicient (Cy: ~ projste ares normal othe wind tram when ued i conjunction with adres force cowie (Ca) of seas. ss delited in spplicaMle cluses (sce Appendix E) when used in ‘conjunction with force woetlsin! (Crp) OF (Cho) reference ates of aneiiares on ower reference aes of fag total projected ars ofthe tower section at height = ~ «reference aren, at height (2), upon which the prssure (px) at that height sts ‘constant for ese of calculation (Paragraph £4.23, Appendix E) dimension use in defining the extent of application of les pressure factors = background factor, which fe « measure of the slowly varying taskgrourd ‘omponent of the fuststing response, caused by low-irequency wind speed seere b= breadth of @ structure or clement, usally normal to the wind sream (sce Figures $2.'C5. C7 of AppendicC, DI of Appendix D. El. £2, E4 and ‘Tobie ES, C4 nd of Appendin E) average ameter ofs circa sation be = dingonal besdih of UHF sntennas fe ~ average diameter or bresdth of section of tower member foe ~ normal beast of UIP antennas me = average treat ofthe suture benween Heights 0 snd sverage eadth of shielding buildings, noma to the wind steam verage breath f the srt hetwcen height and 4 vorage breath of the tp thd of the srsture ty = average rest of the suture at the seston at Het) ‘yw = ratio of the average dlameter of an ancillary to te verage with of structure C= drag force coeffcient for s structure oF member in the direction ofthe wind