Cranes Wind load assessment

Transcription

1 Proväsningsexempar / Preview INTERNATIONAL STANDARD ISO 4302 Second edition Cranes Wind oad assessment Appareis de evage à charge suspendue Évauation des charges dues au vent Reference numer ISO 2016

2 Proväsningsexempar / Preview COPYRIGHT PROTECTED DOCUMENT ISO 2016, Puished in Switzerand A rights reserved. Uness otherwise specified, no part of this puication may e reproduced or utiized otherwise in any form or y any means, eectronic or mechanica, incuding photocopying, or posting on the internet or an intranet, without prior written permission. Permission can e requested from either ISO at the address eow or ISO s memer ody in the country of the requester. ISO copyright office Ch. de Bandonnet 8 CP 401 CH-1214 Vernier, Geneva, Switzerand Te Fax copyright@iso.org ii ISO 2016 A rights reserved

3 Proväsningsexempar / Preview Contents Page Foreword...iv 1 Scope Normative references Terms, definitions, symos and areviated terms Wind pressure In-service wind Genera Action of in-service wind on suspended oad Wind oad cacuations Shape coefficients for individua memers, frames, etc Shieding factors Mutipe frames or memers Wind oads on individua memers (incined to the wind direction) Out-of-service wind Genera Loads due to out-of-service wind Equivaent static out-of-service wind pressure Wind oads on individua memers (incined to the wind direction) Storm wind maps... 9 Annex A (informative) Reference storm wind speeds...11 Biiography...22 ISO 2016 A rights reserved iii

4 Proväsningsexempar / Preview Foreword ISO (the Internationa Organization for Standardization) is a wordwide federation of nationa standards odies (ISO memer odies). The work of preparing Internationa Standards is normay carried out through ISO technica committees. Each memer ody interested in a suject for which a technica committee has een estaished has the right to e represented on that committee. Internationa organizations, governmenta and non-governmenta, in iaison with ISO, aso take part in the work. ISO coaorates cosey with the Internationa Eectrotechnica Commission (IEC) on a matters of eectrotechnica standardization. The procedures used to deveop this document and those intended for its further maintenance are descried in the ISO/IEC Directives, Part 1. In particuar the different approva criteria needed for the different types of ISO documents shoud e noted. This document was drafted in accordance with the editoria rues of the ISO/IEC Directives, Part 2 (see Attention is drawn to the possiiity that some of the eements of this document may e the suject of patent rights. ISO sha not e hed responsie for identifying any or a such patent rights. Detais of any patent rights identified during the deveopment of the document wi e in the Introduction and/or on the ISO ist of patent decarations received (see Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement. For an expanation on the meaning of ISO specific terms and expressions reated to conformity assessment, as we as information aout ISO s adherence to the Word Trade Organization (WTO) principes in the Technica Barriers to Trade (TBT) see the foowing URL: The committee responsie for this document is ISO/96, Cranes, Sucommittee SC 10, Design principes and requirements This second edition cances and repaces the first edition (ISO 4302:1981), which has een technicay revised. A causes have een technicay revised to e aigned with ISO 20332, in comination with ISO , and the informative Annex A, Wind maps, has een added. iv ISO 2016 A rights reserved

5 Proväsningsexempar / Preview INTERNATIONAL STANDARD Cranes Wind oad assessment 1 Scope This Internationa Standard specifies the assessment of wind oads on cranes. It estaishes genera methods for cacuating wind oads (for in-service and out-of-service conditions), which are incuded in the oad cominations stated in ISO and used for proofs of competence such as those given in ISO for the structura components of cranes. It provides a simpified method of cacuation and assumes that the wind may ow horizontay from any direction, the wind ows at a constant speed, there is a static reaction to the wind oad appied to the crane structure. It incudes uit-in aowances for the effects of gusting (fuctuation in wind speed) and for dynamic response. It gives guidance on when to secure the crane for out-of-service conditions. 2 Normative references The foowing documents, in whoe or in part, are normativey referenced in this document and are indispensae for its appication. For dated references, ony the edition cited appies. For undated references, the atest edition of the referenced document (incuding any amendments) appies. ISO :2012, Cranes Design principes for oads and oad cominations Part 1: Genera 3 Terms, definitions, symos and areviated terms For the purposes of this document, the foowing terms and definitions appy. The main symos are given in Tae in-service wind maximum wind that the crane is designed to withstand under operating conditions 3.2 out-of-service wind maximum (storm) wind owing from the east favourae direction that a crane is designed to withstand when in an out-of-service condition ISO 2016 A rights reserved 1

6 Proväsningsexempar / Preview Symo A A H C f, c H D F f rec K F H m H p q(z) R v g v s v s * v(z) v(z)* v m (z) v ref z Characteristic area Tae 1 Main symos Wind area of the suspended oad Shape coefficients Diameter of a circuar section Wind oad Recurrence interva factor Terrain-roughness-coefficient Description Wind oad due to the wind on the hoist oad Mass of the gross or hoist oad in kiograms In-service wind pressure Equivaent static out-of-service wind pressure at height z Recurrence interva 3 s gust ampitude Wind speed, used as a asis of the cacuation Wind speed component acting perpendicuary to the ongitudina axis or surface of a memer Equivaent static out-of-service wind speed at the height z Wind speed component acting perpendicuary to the ongitudina axis of a memer at height z 10 min mean storm wind speed at height z, in metres per second Reference storm wind speed Height aove the surrounding ground eve, in metres Φ 8 Gust response factor θ Ange of the wind direction to the ongitudina axis or face (θ < 90 ) η η w ρ Shieding factor Factor for the remaining hoist oad in out-of-service condition Density of the air 4 Wind pressure The wind pressure, p, is given y the formua 2 p = 05, ρ vs (1) where ρ is the density of air which, for design purposes, is assumed to e constant ρ = 1,225 kg/m 3 ; v s is the wind speed, used as a asis of the cacuation. When using the internationa system of units (SI), where p is expressed in N/m2 and v s in metres per second (m/s), the foowing appies: 2 p = 0, 625 vs (2) 2 ISO 2016 A rights reserved

7 Proväsningsexempar / Preview 5 In-service wind 5.1 Genera The wind oading sha e appied in the east favourae direction in comination with the appropriate oads as defined in ISO :2012, oad cominations B and C. In-service design wind speeds and corresponding pressures sha e either seected ased on Tae 2 or specified ased on the crane configuration, appication and the wind conditions. The in-service design wind speed sha e documented in the operating manua of the crane. Tae 2 In-service design wind speeds v s and pressures p Type of crane or appication Cranes that are easiy secured against wind action and which are designed for operation in ight winds ony (e.g. cranes of ow chassis height with ooms that can e readiy owered to the ground) Design wind speed v s Design wind pressure p m/s N/m A norma types of crane instaed in the open Cranes in process appications, where a crane must continue to work in high winds 28,5 500 The wind speed sha e measured at the highest point of the crane. The in-service design wind speed in Tae 2 is ased on the premise that the crane can e fuy secured in an out-of-service configuration efore the design wind speed is exceeded. As the means for this securing vary y crane type and configuration, the time aowance (e.g. ocking devices at specia ocations of the crane runway, handoperated or automatic rai camps) sha take this into account y a ower eve of wind speed chosen to start the securing. Wind speeds for the use of different crane configurations and for the starting of securing sha e specified. 5.2 Action of in-service wind on suspended oad On a cranes, the action of the wind on the oad must e taken into account and the method y which this is done sha e ceary descried. This may e accompished y use of wind oads on oad parameters of size and shape. The wind oad F H on the oad sha e cacuated as a minimum as foows: F H = c H A H p (3) where F H c H A H p is the wind oad on the suspended oad in the direction of the wind; is the shape coefficient of the suspended oad; is the wind area of the hoist oad; is the wind pressure corresponding to appropriate design condition. In the asence of detaied information on the oad it sha e assumed that c H = 2,4 and A H = 0,000 5 m H, where A H is expressed in square metres (m 2 ) and m H is the mass of the hoist oad in kiograms (kg). Additionay, the effects of wind actions on the oad may e imited y a reduction of the rated oad ased upon wind speed, oad area and shape factor, a imitation of the in-service wind speed for oads exceeding a stipuated surface area. ISO 2016 A rights reserved 3

8 Proväsningsexempar / Preview 5.3 Wind oad cacuations For crane structures or individua memers used in crane structures the wind oad, F, in the direction of the wind, is cacuated from the formua: F = A p C f (4) where F is the wind oad acting perpendicuary to the ongitudina axis of the memer (see 5.6) A p C f is the characteristic area, i.e. the projection of the soid area of the memer on to a pane perpendicuar to the wind direction; is the wind pressure corresponding to appropriate design condition; is the shape coefficient for the memer under consideration, with reference to the wind direction and the characteristic area (see 5.4). Vaues sha e either those given in Tae 3 or those derived y recognized theoretica or experimenta methods (e.g. wind tunne or fu scae tests), or other recognized sources. The tota wind oad on the structure is taken as the sum of the oads on its memers. 5.4 Shape coefficients for individua memers, frames, etc Shape coefficients, C f, for individua memers, singe attice frames, and machinery houses, etc. vary according to the aerodynamic senderness and, in the case of arge ox sections, with the section ratio. Aerodynamic senderness and section ratio are defined in Figure 1. Where a frame is made up of fat-sided and circuar sections, or of circuar sections in oth fow regimes (D v s < 6 m 2 /s and D v s 6 m 2 /s, with D the diameter of a circuar section in metres, and v s the design wind speed in metres per second, the appropriate shape coefficients are appied to the corresponding fronta areas. Tae 3 Shape coefficients C f per aerodynamic senderness Type Individua memers Singe attice frames Machinery houses, etc. Description Aerodynamic senderness / or /D (see Figure 1) Roed sections, rectanges, hoow sections, fat pates 1,3 1,35 1,6 1,65 1,7 1,9 Circuar sections where D v s < 6 m 2 /s 0,75 0,80 0,90 0,95 1,0 1,1 Circuar sections where D v s 6 m 2 /s 0,60 0,65 0,70 0,70 0,75 0,8 Box sections over 350 mm square and 250 mm, 450 mm rectanguar /d Fat sided sections 1,7 Circuar sections where D v s < 6 m 2 /s 1,2 Circuar sections where D v s 6 m2/s 0,8 Rectanguar cad structures on ground or soid ase (air fow eneath structure prevented) 2 1,55 1,75 1,95 2,1 2,2 1 1,40 1,55 1,75 1,85 1,9 0,5 1,0 1,2 1,3 1,35 1,4 0,25 0,8 0,9 0,9 1,0 1,0 1,1 4 ISO 2016 A rights reserved

9 Proväsningsexempar / Preview 1 d D ength of memer Aerodynamicsenderness ength of memer = = readth of sectionacrosswindfront or D readth of section across wind front Sectionratio(for oxsections) = depthofsection paraetowindfow = d Key 1 wind direction Figure 1 Aerodynamic senderness and section ratio 5.5 Shieding factors Mutipe frames or memers Where parae frames or memers are positioned so that shieding takes pace, the wind oad on the windward frame or memer and on the unshetered parts of those ehind it are cacuated using the appropriate shape coefficients. The shape coefficients on the shetered parts are mutipied y a shieding factor, η, given in Tae 4. Vaues of η vary with the soidity and spacing ratios as defined in Figure 2. Spacing ratio a/ Tae 4 Shieding factors (η) Soidity ratio (see Figure 2) A/A e 0,1 0,2 0,3 0,4 0,5 0,6 0,5 0,75 0,4 0,32 0,21 0,15 0,1 1,0 0,92 0,75 0,59 0,43 0,25 0,1 2,0 0,95 0,8 0,63 0,5 0,33 0,2 4,0 1 0,88 0,76 0,66 0,55 0,45 5,0 1 0,95 0,88 0,81 0,75 0,68 6, ISO 2016 A rights reserved 5

10 Proväsningsexempar / Preview a) Soidity ratio 1 a a a ) Spacing ratio A area of soidparts(shownshaded) A Soidity ratio A = e encosed area = memers distance etween facing sides Spacingratio = readth of memer across wind front = a Key 1 wind direction Figure 2 Soidity ratio and spacing ratio Where there are a numer of identica frames or memers spaced equidistanty ehind one another in such a way that each frame shieds those ehind it, it is accepted that the shieding effect increases up to the ninth frame and remains constant thereafter. The wind oads are cacuated from Formuae (5) and (6). On the first eight frames: where n 1 η Fn = A p Cf 1 η (5) 6 ISO 2016 A rights reserved

11 Proväsningsexempar / Preview F n η A p C f is the wind oad on the nth frame; is the shieding factor; is the characteristic area, i.e. the projection of the soid area of the memer on to a pane perpendicuar to the wind direction; is the wind pressure corresponding to appropriate design condition; is the shape coefficient for the memer under consideration, with reference to the wind direction and the characteristic area (see 5.4). Vaues sha e either those given in Tae 3 or those derived y recognized theoretica or experimenta methods (e.g. wind tunne or fu scae tests), or other recognized sources. On the 9th and susequent frames: F n A p C ( n ) = 9 1 η 8 + ( 9) η 9 1 η f (6) For design purposes the term η x used in Formuae (5) and (6) sha e taken as 0,10 whenever it is numericay ess than 0, Wind oads on individua memers (incined to the wind direction) Where the wind ows at an ange to the ongitudina axis of a memer or to its surface, the wind oad acting perpendicuary to the ongitudina axis or surface is otained y using, in Formua (1), the wind speed component v s * cacuated y v * s where = v sinθ (7) s v s * v s is the wind speed component acting perpendicuary to the ongitudina axis or surface; is the wind speed, used as a asis of the cacuation; θ is the ange of the wind to the ongitudina axis or surface (θ < 90 ). 6 Out-of-service wind 6.1 Genera The speed of the out-of-service wind (3.2) varies with the geographica ocation and the degree of exposure to prevaiing winds. Cranes with parts that can e readiy owered to the ground, e.g. with teescoping jis or with towers that are readiy teescoped y means of sef-contained mechanisms, or cranes aowed to weathervane (sef-aigning into a most favourae position), need ony e designed for out-of-service wind in this position. Operating instructions for such cranes sha incude the requirement that a parts e secured from wind exposure when not in service. The operating instructions for cranes that require the instaation of wind staiizers, or other means not used during operation, in order to resist the specified out-of-service wind speed sha state the wind speed that the crane can safey sustain in its operating configuration; they sha aso descrie the provisions that must e foowed in order that the crane may safey withstand the specified out-ofservice wind. ISO 2016 A rights reserved 7