SIST EN 13001-2:2005+A3:2009

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Kransicherheit - Konstruktion allgemein - Teil 2: LasteinwirkungenSécurité des appareils de levage à charge suspendue - Conception générale - Partie 2: Effets de chargeCrane safety - General design - Part 2: Load effects53.020.20DvigalaCranesICS:Ta slovenski standard je istoveten z:EN 13001-2:2004+A3:2009SIST EN 13001-2:2005+A3:2009en01-september-2009SIST EN 13001-2:2005+A3:2009SLOVENSKI
STANDARD



SIST EN 13001-2:2005+A3:2009



EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 13001-2:2004+A3
June 2009 ICS 53.020.20 Supersedes EN 13001-2:2004+A2:2009English Version
Crane safety - General design - Part 2: Load effects
Sécurité des appareils de levage à charge suspendue - Conception générale - Partie 2: Effets de charge
Kransicherheit - Konstruktion allgemein - Teil 2: Lasteinwirkungen This European Standard was approved by CEN on 2 March 2004 and includes Corrigendum 1 issued by CEN on 5 July 2006, Amendment 1 approved by CEN on 18 September 2006, Amendment 2 approved by CEN on 5 January 2009 and Amendment 3 approved by CEN on 16 May 2009.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre:
Avenue Marnix 17,
B-1000 Brussels © 2009 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 13001-2:2004+A3:2009: ESIST EN 13001-2:2005+A3:2009



EN 13001-2:2004+A3:2009 (E) 2 Contents Page Foreword . 3 Introduction . 4 1 Scope. 4 2 Normative references . 5 3 Terms, definitions, symbols and abbreviations . 5 3.1 Terms and definitions . 5 3.2 Symbols and abbreviations . 5 4 Safety requirements and/or measures. 10 4.1 General . 10 4.2 Loads . 10 4.2.1 General . 10 4.2.2 Regular loads . 11 4.2.3 Occasional loads . 17 4.2.4 Exceptional loads . 24 4.2.5 Loads on means provided for access . 30 4.3 Load combinations . 30 4.3.1 General . 30 4.3.2 High risk applications . 30 4.3.3
!!!!Mass distribution classes MDC1 and MDC2"""". 31 4.3.4 !!!!Partial safety factors for the mass of the crane"""" . 31 4.3.5 Partial safety factors to be applied to loads caused by displacements . 32 4.3.6 Survey of load combinations . 33 4.3.7 Partial safety factors for the proof of rigid body stability. 37 Annex A (normative)
Aerodynamic coefficients . 40 A.1 General . 40 A.2 Individual members . 43 A.3 Plane and spatial lattice structure members . 47 A.4 Structural members in multiple arrangement . 51 Annex B (informative)
Selection of a suitable set of crane standards for a given application . 54 Annex ZA (informative)
Relationship between this European Standard and the Essential Requirements of EU Directive 98/37/EC . 55 Annex ZB (informative)
####Relationship between this European Standard and the Essential Requirements of EU Directive 2006/42/EC$$$$ . 56 Bibliography . 57
SIST EN 13001-2:2005+A3:2009



EN 13001-2:2004+A3:2009 (E) 3 Foreword This document (EN 13001-2:2004+A3:2009) has been prepared by Technical Committee CEN/TC 147 “Cranes — Safety”, the secretariat of which is held by BSI. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by December 2009, and conflicting national standards shall be withdrawn at the latest by December 2009. This European Standard was approved by CEN on 2 March 2004 and includes Corrigendum 1 issued by CEN on 5 July 2006, Amendment 1 approved by CEN on 18 September 2006, Amendment 2 approved by CEN on 5 January 2009 and Amendment 3 approved by CEN on 16 May 2009. This document supersedes %EN 13001-2:2004+A2:2009&. The start and finish of text introduced or altered by amendment is indicated in the text by tags
!", # $ and %&. The modifications of the related CEN Corrigendum have been implemented at the appropriate places in the text and are indicated by the tags ˜ ™. #This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association, and supports essential requirements of EC Directive(s). For relationship with EC Directive(s), see informative Annexes ZA and ZB, which are integral parts of this document.$ Annex A is normative, Annex B is informative. This European Standard is one Part of EN 13001. The other parts are as follows: Part 1: General principles and requirements Part 2: Load actions Part 3.1: Limit states and proof of competence of steel structures Part 3.2: Limit states and proof of competence of rope reeving components Part 3.3: Limit states and proof of competence of wheel/rail contacts Part 3.4: Limit states and proof of competence of machinery According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. SIST EN 13001-2:2005+A3:2009



EN 13001-2:2004+A3:2009 (E) 4 Introduction This European Standard has been prepared to be a harmonised standard to provide one means for the mechanical design and theoretical verification of cranes to conform with the essential health and safety requirements of the Machinery Directive, as amended. This standard also establishes interfaces between the user (purchaser) and the designer, as well as between the designer and the component manufacturer, in order to form a basis for selecting cranes and components. This European Standard is a type C standard as stated in the ˜EN ISO 12100-1™. The machinery concerned and the extent to which hazards are covered are indicated in the scope of this standard. When provisions of this type C standard are different from those, which are stated in type A or B standards, the provisions of this type C standard take precedence over the provisions of the other standards, for machines that have been designed and built according to the provisions of this type C standard. 1 Scope This European Standard is to be used together with Part 1 and Part 3 and as such they specify general conditions, requirements and methods to prevent hazards of cranes by design and theoretical verification. Part 3 is only at pre-drafting stage; the use of Parts 1 and 2 is not conditional to the publication of Part 3. NOTE Specific requirements for particular types of crane are given in the appropriate European Standard for the particular crane type. The following is a list of significant hazardous situations and hazardous events that could result in risks to persons during normal use and foreseeable misuse. Clause 4 of this standard is necessary to reduce or eliminate the risks associated with the following hazards: a) Rigid body instability of the crane or its parts (tilting and shifting). b) Exceeding the limits of strength (yield, ultimate, fatigue). c) Elastic instability of the crane or its parts (buckling, bulging). d) Exceeding temperature limits of material or components. e) Exceeding the deformation limits. This European Standard is applicable to cranes which are manufactured after the date of approval by CEN of this standard and serves as reference base for the European Standards for particular crane types. SIST EN 13001-2:2005+A3:2009



EN 13001-2:2004+A3:2009 (E) 5
2 Normative references This European Standard incorporates, by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to, or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest editions of the publication referred to applies (including amendments). EN ISO 12100-1:2003, Safety of machinery — Basic concepts, general principles for design — Part 1: Basic terminology, methodology (ISO 12100-1:2003). EN ISO 12100-2:2003, Safety of machinery — Basic concepts, general principles for design — Part 2: Technical principles and specifications (ISO 12100-2:2003). ˜deleted text™ ˜EN 1990:2002, Eurocode — Basic of structural design™. EN 13001-1, Cranes — General Design — Part 1: General principles and requirements. ISO 4306-1: 1990, Cranes — Vocabulary — Part 1: General. 3 Terms, definitions, symbols and abbreviations 3.1 Terms and definitions For the purposes of this European Standard, the terms and definitions given in ˜deleted text™,
˜EN 1990:2002™ and clause 6 of ISO 4306-1:1990 apply. 3.2 Symbols and abbreviations For the purposes of this European Standard, the symbols and abbreviations given in Table 1 apply. SIST EN 13001-2:2005+A3:2009



EN 13001-2:2004+A3:2009 (E) 6
Table 1 — Symbols and abbreviations Symbols, abbreviations Description
A1 to A4 Load combinations including regular loads A Characteristic area of a crane member Ag Projection of the gross load on a plane normal to the direction of the wind velocity Ac Area enclosed by the boundary of a lattice work member in the plane of its characteristic height d Aj Area of an individual crane member projected to the plane of the
characteristic height d bh Width of the rail head b Characteristic width of a crane member B1 to B5 Load combinations including regular and occasional loads c Spring constant ca, coy, coz Aerodynamic coefficients co ˜Aerodynamic coefficient™ C1 to C9 Load combinations including regular, occasional and exceptional loads CFF, CFM Coupled wheel pairs of system F/F or F/M d Characteristic dimension of a crane member SIST EN 13001-2:2005+A3:2009



EN 13001-2:2004+A3:2009 (E) 7
Table 1 (continued) Symbols, abbreviations Description di, dn Distance between wheel pair i or n and the guide means eG Width of the gap of a rail f Friction coefficient fi Loads fq natural frequency frec Term used in calculating v(z) F Force F, Fy, Fz Wind loads Fb Buffer force Fˆ Maximum buffer force Fi, Ff Initial and final drive force ∆F Change of drive force Fx1i, Fx2i Tangential wheel forces Fy1i, Fy2i Fy Guide force Fz1i, Fz2i Vertical wheel forces F/F, F/M Abbreviations for Fixed/Fixed and Fixed/Moveable, characterizing the possibility of lateral movements of the crane wheels g Gravity constant h Distance between instantaneous slide pole and guide means of a skewing crane h(t) Time-dependent unevenness function hs Height of the step of a rail H1, H2 Lateral wheel forces induced by drive forces acting on a crane or trolley with asymmetrical mass distribution HC1 to HC4 Hoisting classes HD1 to HD5 Classes of the type of hoist drive and its operation method i Serial number IFF, IFM Independent wheel pairs of system F/F or F/M j Serial number k Serial number K Drag-coefficient of
terrain K1, K2 Roughness factors l Span of a crane la Aerodynamic length of a crane member lo Geometric length of a crane member mH Mass of the gross or hoist load SIST EN 13001-2:2005+A3:2009



EN 13001-2:2004+A3:2009 (E) 8 Table 1 (continued) Symbols, abbreviations Description m Mass of the crane and the hoist load ∆mH Released or dropped part of the hoist load MDC1, MDC2 Mass distribution classes n Number of wheels at each side of the crane runway nr Exponent used in calculating γn nm Exponent used in calculating the shielding factor η p Number of pairs of coupled wheels q Equivalent static wind pressure q Mean wind pressure q(z) Equivalent static storm wind pressure q(3) Wind pressure at v (3) r Wheel radius R Stormwind recurrence interval Re Reynold number sg Slack of the guide sy Lateral slip at the guide means syi Lateral slip at wheel pair i S Load effect Sˆ Maximum load effect S1, S2 Stability classes Si, Sf Initial and final load effects ∆S Change of load effect t Time u Buffer stroke û Maximum buffer stroke v Travelling speed of the crane v Constant mean wind velocity v* Constant mean wind velocity if the wind direction is not normal to the longitudinal axis of the crane member under consideration v(z) Equivalent static storm wind velocity v(z)* Equivalent static storm wind velocity if the wind direction is not normal to the longitudinal axis of the crane member under consideration v(3) Gust wind velocity averaged of a period of 3 seconds vg Three seconds gust amplitude vh Hoisting speed vh,max Maximum steady hoisting speed vh,CS Steady hoisting creep speed SIST EN 13001-2:2005+A3:2009



EN 13001-2:2004+A3:2009 (E) 9 Table 1 (continued) Symbols, abbreviations Description vm(z) Ten minutes mean storm wind velocity in the height z vref Reference storm wind velocity wb Distance between the guide means z Height above ground level z(t) Time-dependent coordinate of the mass centre αr Relative aerodynamic length αw Angle between the direction of the wind velocity v or v(z) and the longitudinal axis of the crane member under consideration α Skewing angle αg Part of the skewing angle α due to the slack of the guide αG Term used in calculating φ4 αs Term used in calculating φ4 αt Part of the skewing angle α due to tolerances αw Part of the skewing angle α due to wear β Angle between horizontal plane and non-horizontal wind direction β2 Term used in calculating φ2 β3 Term used in calculating φ3 γf Overall safety factor γm Resistance coefficient γn Risk coefficient γp Partial safety factor δ Term used in calculating φ1 εS Conventional start force factor εM Conventional mean drive force factor η Shielding factor ηW Factor for remaining hoist load in out of service condition λ Aerodynamic slenderness ratio µ, µ′ Parts of the span l F Term used in calculating the guide force Fy F1i, F2i Terms used in calculating Fy1i and Fy2i ξ Term used in calculating φ7 ξ1i, ξ2i Term used in calculating Fx1i and Fx2i ξG(αG), ξs(αs) Curve factors ρ Density of the air ϕ Solidity ratio φi Dynamic factors SIST EN 13001-2:2005+A3:2009



EN 13001-2:2004+A3:2009 (E) 10 Table 1 (concluded) Symbols, abbreviations Description φ1 Dynamic factor for hoisting and gravity effects acting on the mass of the crane φ2 Dynamic factor for inertial and gravity effects by hoisting an
unrestrained grounded load φ2min Term used in calculating φ2 φ3 Dynamic factor for inertial and gravity effects by sudden release of a part of the hoist load φ4 Dynamic factor for loads caused by travelling on uneven surface φ5 Dynamic factor for loads caused by acceleration of all crane drives φ6 Dynamic factor for test loads φ7 Dynamic factor for loads due to buffer forces φ8 Gust response factor ψ Reduction factor used in calculating
aerodynamic coefficients
4 Safety requirements and/or measures 4.1 General Machinery shall conform to the safety requirements and/or measures of this clause. In addition, the machine shall be designed according to the principles of EN ISO 12100-1:2003 and EN ISO 12100-2:2003 for hazards relevant but not significant which are not dealt with by this document (e. g. sharp edges).
4.2 Loads 4.2.1 General 4.2.1.1 Introduction The loads acting on a crane are divided into the categories of regular, occasional and exceptional as given in 4.2.1.2, 4.2.1.3 and 4.2.1.4. For the proof calculation of means of access loads only acting locally are given in ˜4.2.5™. These loads shall be considered in proof against failure by uncontrolled movement, yielding, elastic instability and, where applicable, against fatigue. 4.2.1.2 Regular loads
a) hoisting and gravity effects acting on the mass of the crane; b) inertial and gravity effects acting vertically on the hoist load; c) loads caused by travelling on uneven surface; d) loads caused by acceleration of all crane drives; SIST EN 13001-2:2005+A3:2009



EN 13001-2:2004+A3:2009 (E) 11 e) loads induced by displacements. Regular loads occur frequently under normal operation. 4.2.1.3 Occasional loads
a) loads due to in-service wind; b) snow and ice loads; c) loads due to temperature variation; d) loads caused by skewing. NOTE Occasional loads occur infrequently. They are usually neglected in fatigue assessment. 4.2.1.4 Exceptional loads
a) loads caused by hoisting a grounded load under exceptional circumstances; b) loads due to out-of-service wind; c) test loads; d) loads due to buffer forces; e) loads due to tilting forces; f) loads caused by emergency cut-out; g) loads caused by failure of mechanism or components; h) loads due to external excitation of crane foundation; i) loads caused by erection and dismantling. NOTE Exceptional loads are also infrequent and are likewise usually excluded from fatigue assessment. 4.2.2 Regular loads 4.2.2.1 !!!!Hoisting and gravity effects acting on the mass of the crane When lifting the load off the ground or when releasing the load or parts of the load vibrational excitation of the crane structure shall be taken into account. The gravitational force induced by the mass of the crane or crane parts shall be multiplied by the factor φ1. The masses of cranes or crane parts in class MDC1 (see 4.3.3) shall be multiplied by 1,00,11≤≤δ+=δφ (1) The value of δ depends on the crane structure and shall be specified. The divisions of masses of crane parts in class MDC2 (see 4.3.3) shall be multiplied by 05,00,11≤≤δ±=δφ (2) depending on whether their gravitational acting is partly increasing (+δ) or decreasing (-δ) the resulting load effects in the critical points selected for the proof calculation. SIST EN 13001-2:2005+A3:2009



EN 13001-2:2004+A3:2009 (E) 12 The mass of the crane includes those components which are always in place during operation except for the net load itself. For some cranes or applications, it may be necessary to add mass to account for accumulation of debris." 4.2.2.2 Inertial and gravity effects acting vertically on the hoist load 4.2.2.2.1 Hoisting an unrestrained grounded load In the case of hoisting an unrestrained grounded load, the hereby induced vibrational effects
shall be taken into account by multiplying the gravitational force due to the mass of the hoist load by a factor φ2 (see Figure 1). The mass of the hoist load includes the masses of the payload, lifting attachments and a portion of the suspended hoist ropes or chains etc.
Figure 1 — Factor φφφφ2 The factor φ2 shall be taken as follows: hv2min,22+φ=φ (3) φ2,min and β2 are given in Table 2 for the appropriate hoisting class. For the purposes of this standard, cranes are assigned to hoisting classes ranging from HC1 to HC4 according to their dynamic and elastic characteristics. HC1 requires a flexible structure and a drive system with smooth dynamic characteristics, whereas a rigid structure and a drive system with sudden speed changes imply HC4. The selection of hoisting classes depends on the particular type of cranes and is dealt with in the European Standards for specific crane types, see annex B. Equally, values of φ2 can be determined by experiments or analysis without reference to hoisting class. vh is the steady hoisting speed, in meters per second, related to the lifting attachment. Values of vh are given in Table 3. Table 2 — Values of ββββ2 and φφφφ2,min
Hoisting class of appliance ββββ2 φφφφ2,min HC1 0,17 1,05 HC2 0,34 1,10 HC3 0,51 1,15 HC4 0,68 1,20
SIST EN 13001-2:2005+A3:2009



EN 13001-2:2004+A3:2009 (E) 13 Table 3 — Values of vh for estimation of φφφφ2 Load combination (see 4.3.6) Type of hoist drive and its operation method HD1 HD2 HD3 HD4 HD5 A1, B1 vh,max vh,CS vh,CS 0,5 ⋅ vh,max vh = 0 C1 – vh,max – vh,max 0,5 × vh,max
%Where HD 1: Creep speed is not available, or the start of the lift without creep speed is possible HD 2: Start of the lift is only possible at creep speed
HD 3: Hoist drive control maintains a steady creep speed until the load is lifted off the ground HD 4: Start of the lift is performed with continuously increasing speed
HD 5: Hoist drive control is automatic and ensures that the speed influence on the dynamic force is negligible& vh,max is the maximum steady hoisting speed; vh,CS is the steady hoisting creep speed. 4.2.2.2.2 Sudden release of a part of the hoist load For cranes that release a part of the hoist load as a normal working procedure, the peak dynamic action on the crane can be taken into account by multiplying the hoist load by the factor φ3 (see Figure 2).
Figure 2 — Factor φφφφ3 The factor φ3 shall be taken as follows: ()3311mmHH+∆−=φ (4) where: ∆mH
is the released part of the hoist load; SIST EN 13001-2:2005+A3:2009



EN 13001-2:2004+A3:2009 (E) 14 mH
is the mass of the hoist load; β3 = 0,5
for cranes equipped with grabs or similar slow-release devices; β3 = 1,0
for cranes equipped with magnets or similar rapid-release devices. 4.2.2.3 Loads caused by travelling on uneven surface The dynamic actions on the crane by travelling, with or without load, on or off roadways or on rail tracks shall be estimated, by experiment or by calculation using an appropriate model for the crane or the trolley and the travel surface or the track, and shall be specified. When calculating the dynamic actions on the crane by travelling, the induced accelerations shall be taken into account by multiplying the gravitational forces due to the masses of the crane and hoist load by a factor φ4. European Standards for specific crane types specify tolerances for rail tracks and ground conditions and give conventional values for φ4. Where there is no specific factor φ4, it may be estimated by using a simple single mass - spring - model for the crane as shown in Figure 3.
Key m mass of the crane and the hoist load; v constant horizontal travelling speedof the crane; c spring constant; z(t) coordinate of the mass centre; h(t) unevenness function describing the step or gap of the rail; Figure 3 — Single mass model of a crane for determining the factor φφφφ4 φ4 may be calculated as follows: sξπφr gv21224+= (5) for travelling over a step (see Figure 4a); G224r gv21ξπφ+= (6) for travelling over a gap (see Figure 4b); where: SIST EN 13001-2:2005+A3:2009



EN 13001-2:2004+A3:2009 (E) 15 v is the constant horizontal travelling speed of the crane; r is the wheel radius;
g = 9,81 m/s2is the gravity constant; ξs(αs), ξG(αG) are curve factors that become maximum for the time period after the wheel has passed the unevenness; they can be determined for αs < 1,3 and αG < 1,3 by the diagrams given in Figure 5; where: sshr2vh2qsf=α
(see Figure 5a); veGGqf=α
(see Figure 5b); hs is the height of the step (see Figure 4); eG is the width of the gap (see Figure 4); fq = π2/cm is the natural frequency of a single mass model of the crane (see Figure 3). If unknown, to be taken as 10 Hz.
a) Travelling over a step b) Travelling over a gap Figure 4 — Movement of the wheel centre SIST EN 13001-2:2005+A3:2009



EN 13001-2:2004+A3:2009 (E) 16
˜
™ a) Travelling over a step b) Travelling over a gap Figure 5 — Curve factors ξξξξs(ααααs) and ξξξξG(ααααG) NOTE The use of this simple model is restricted to cranes whose actual dynamic behaviour corresponds to that of the model. If more than one natural mode contributes a significant response and/or rotation occurs, the designer should estimate the dynamic loads using an appropriate model for the circumstances. 4.2.2.4 Loads caused by acceleration of drives Loads induced in a crane by acceleration or decelerations caused by drive forces may be calculated using rigid body kinetic models. For this purpose, the gross load is taken to be fixed at the top of the jib or immediately below the crab. The load effect Sˆ shall be applied to the components exposed to the drive forces and where applicable to the crane and the gross load as well. As a rigid body analysis does not directly reflect elastic effects, the load effect Sˆ shall be calculated by using a factor φ5 as follows (see Figure 6): SSSi∆+=5ˆφ (7) where: ∆S=Sf -Si is the change of the load effect due to the change of the drive force ∆F = Ff - Fi; Si, Sf are the initial (i) and final (f) load effects caused by Fi and Ff; Fi, Ff are the initial (i) and final (f) drive forces. SIST EN 13001-2:2005+A3:2009



EN 13001-2:2004+A3:2009 (E) 17 a) for the change of drive forces from steady state b) for the positioning case Figure 6 — Factor φφφφ5 Following values of φ5 shall be applied: φ5 = 1 for centrifugal forces; 1 ≤ φ5 ≤ 1,5 for drives with no backlash or in cases where existing backlash does not affect the dynamic forces and with smooth change of forces; 1,5 ≤ φ5 ≤ 2 for drives with no backlash or in cases where existing backlash does not affect the dynamic forces and with sudden change of forces; φ5 = 3 for drives with considerable backlash, if not estimated more accurate by using a spring-mass-model. Where a force that can be transmitted is limited by friction or by the nature of the drive mechanism, the limited force and a factor φ5 appropriate to that system shall be used. 4.2.2.5 Loads induced by displacements Account shall be taken of loads arising from displacements included in the design such as those within the limits necessary to initiate response from compensating systems (e.g. skewing) or those resulting from prestressing. Other loads to be considered include those that can arise from displacements that are within defined limits such as those set for the variations in the height or the gauge betw
...