Germany

For altitudes 800 s a * 1100 m the attitude factor is For altitudes > 1100 m special requirements are necessary. (2) In zone 2 and for a > 800 m (Harz) special requirements are necessary. (3) In all other cases the attitude factor is (4) The terrain category I is only applicable in zone 4. (6) The reduction factor for temporary structures is to be considered as follows Measures in the case of a wind storm

Ireland Wind Standared

(1) Unless specific values are given from the meteorological service in Dublin, the direction factor is to be considered by (3) For sites up to altitudes of 250m the altitude factor is given by For altitudes more than 250m, advice may be available from the meteorological service in Dublin. Figure A3 Ireland - wind map (reference wind velocity)

United Kingdom

(1) The values of reference wind velocity vref0 at sea level are derived from q analysis. 3s where altitude above sea level m of the site when topography is not significant or else the altitude of the ground level at the base of the hill or escarpment when topography is significant (see 8.4) measured from mean sea level. (3) Values for the directional factor are given in Table A4. Use of these values for all possible wind directions gives the design overall risk of exceedence distribue-ted...

Pbf

B) Edge of face flush with edge of lower storey Figure D.10 Key for walls of inset storey D.3 External pressure coefficients for flat roofs of buildings D.3.1.1 A general method for determining the wind pressures on flat, or nearly flat roofs of buildings with any arbitrary plan shape is given in D.3.2. This general method also accounts for the variations in high local suction around the periphery of the roof caused by various common forms of eaves detail. D.3.1.2 A simpler method, restricted...

Background to the Eurocode Programme

(4) The Commission of the European Communities (CEC) initiated the work of establishing a set of harmonized technical rules for the design of building and civil engineering works which would initially serve as an alternative to the different rules in force in the various Member States and would ultimately replace them. These technical rules became known as the Structural Eurocodes. (5) In 1990, after consulting their respective Member States, the CEC transferred the work of further development,...

Distinction between principles and application rules

(1) Depending on the character of the individual clauses, distinction is made in this Part between principles and application rules. - general statements and definitions for which there is no alternative, as well as - requirements and analytical models for which no alternative is permitted unless specifically stated. (3) The principles are identified by the letter P following the paragraph number. (4) The application rules are generally recognized rules which follow the principles and satisfy...

Dynamic coefficient for gust wind response

(1) Values of cd set out in Figures 9.1 to 9.8 are based on typical values of the relevant parameters and the simple equations for frequency given in annex C. For conventional structures these assumptions and equations have been found to be reasonable and the Figures provide upper bound values to cd within the field of application in the Figures. In particular the values are conservative for structures sited in categories II to IV. Caution should be exercised for special structures of unusual...

Field of application

(1) Buildings whose geometric dimensions satisfy the criteria given in Figure 9.9 need not be checked for vortex shedding and galloping. Buildings which do not satisfy these cntena shall be checked for vortex shedding and galloping. (2) Elongated structures, such as chimneys and bridges, whose geometric dimensions satisfy the criteria given in Figures 9.5 to 9.9 (chimneys) and Table 9.1 (bridges) need not to be checked for vortex shedding, galloping, flutter and interference galloping. Such...

Djf

Terrain factor torsional stiffness K factor length of a horizontal structure m mass per unit length equivalent mass per unit length n exponent ni natural frequency of the structure of the mode i 1.x fundamental frequency of alongwind vibration ni.y fundamental frequency of crosswind vibration P annual probability of exceedence In* reference mean velocity pressure averaging time of the reference wind speed, plate thickness cg onset wind velocity for galloping gig critical wind velocity for...

Info

Reciprocal Strouhal numbers of coupled stacks with in-line and grouped arrangements C.3.3 Divergence and flutter C.3.3.1 General (1) Divergence and flutter are instabilities that can only occur for flexible plate-like structures, such as signboards or suspension-bridge decks, above a certain threshold or critical wind velocity. In both cases the instability is caused by the deflection of the structure modifying the aerodynamics to alter the loading. (2) Divergence and flutter shall essentially...

Latin uppercase letters

Fi vortex exciting force at point j of the structure H height of a topographic feature Kfo x interference factor for buffeting, along wind response x interference factor for buffeting, along wind acceleration K interference factor for vortex shedding Km reduction factor for parapets Kw effective correlation length factor -e effective length of an upwind slope Li(z) integral length scale of turbulence Lj effective correlation length j actual length of an upwind slope Ng number of loads for gust...

List of references see clause

ENV 1991 Part 1 1994 ENV 1991 Part 2.1 1995 ENV 1991 Part 2.3 1995 ENV 1991 Part 2.5 1997 ENV 1991 Part 2.6 1997 ENV 1991 Part 2.7 1998 ENV 1991 Part 3 1995 ENV 1997 Part 1 1994 Eurocode 1 Basis of design and actions on structures Part 1 Basis of design. Eurocode 1 Basis of design and actions on structures Part 2-1 Actions on structures Densities, self weight and imposed loads. Eurocode 1 Basis of design and actions on structures Part 2-2 Actions on structures Actions on structures exposed to...

Matters Specific to this Prestandard

(16) The scope of Eurocode 1 is defined in clause 1.1.1 and the scope of this part of Eurocode 1 is defined in 1.1.2. Additional parts of Eurocode 1 which are planned are indicated in clause 1.1.3. (17) This Part is complemented by a number of informative annexes. (18) The relevant wind parameters (the basic value of the reference wind velocity and various factors and parameters) shall be provided in the form of maps or otherwise (see annex A) by the Relevant Authority. The value of the...

Modelling of wind actions

(1 )P The wind action is represented either as a wind pressure or a wind force. The action on the structure caused by the wind pressure is assumed to act normal to the surface except where otherwise specified e.g. for tangential friction forces. (2) The following parameters are used several times and are defined below Ont reference mean wind velocity pressure derived from reference wind velocity as defined in 7.1. It is used as the characteristic value ce(z) exposure coefficient accounting for...

National Application Document Part A Buildings

3 Partial safety factors, combination factors and other values 5 Additional recommendations Annexes A (normative) Photographs diagrams of terrain categories B (normative) Treatment of transition between terrain categories xv C (normative) Treatment of minimum height and effect of obstructions xxiv D (normative) Directional pressure coefficients for buildings xxv E (normative) Wind structure incorporating the principles of BS 6399 Part 2 lv Tables --- B.l Values of transition factor D.l Dynamic...

National foreword

This Draft for Development was prepared by Subcommittee B 525 1 and is the English language version of ENV1991-2-4 1995 Eurocode 1 Basis of design and actions on structures Part 2.4 Actions on structures Wind actions as published by the European Committee for Standardization (CEN). This Draft for Development also includes the United Kingdom (UK) National Application Document (NAD) to be used with the ENV in the design of buildings and bridges to be constructed in the UK or in UK loading. ENV...

Objectives of the Eurocodes

(1) The Structural Eurocodes comprise a group of standards for the structural and geotechnical design of buildings and civil engineering works. (2) They cover execution and control only to the extent that is necessary to indicate the quality of the construction products, and the standard of the workmanship, needed to comply with the assumptions of the design rules. (3) Until the necessary set of harmonised technical specifications for products and for methods of testing their performance are...

Requirements for testing

(1) P If experimental tests are undertaken, they shall be carried out on a properly scaled model of the actual full scale situation. (2) The following conditions shall be satisfied - the natural wind shall be modelled to account for the variation of mean wind speed with height above grounds as appropriate to the terrain of the site, - the natural wind shall be modelled to account for the correct turbulence as appropriate to the terrain of the site.

Section Aerodynamic coefficients

(1 ) This section presents the aerodynamic coefficients of the following structures, structural elements and components - Free-standing boundary walls, fences and signbords (10.4) - Structural elements with rectangular section (10.5) - Structural elements with sharp edged section (10.6) - Structural elements with regular polygonal section (10.7) - Lattice structures and scaffoldings (10.10) - Bridges (10.11) -Flags (10.12) - Friction coefficients (10.13) - Effective slenderness and slendemess...

Section Choice of procedures

(1 )P Two procedures for calculating wind loads are provided. - the simple procedure applies to those structures whose structural properties do not make them susceptible to dynamic excitation. This procedure can also be used for the design of mildly dynamic structures by the use of the dynamic coefficient, c& The value of this coefficient depends upon the type of structure (concrete, steel, composite), the height of the structure and its breadth. - the detailed procedure applies to those...

Section Design situations

(1)P The relevant wind actions shall be determined for each design situation identified In accordance with ENV 1991 -1. (2)P The effect of other actions on structures (such as snow, traffic or ice) which will modify the reference area or coefficients shall be taken into account. The effect of changes of the form of the construction works which may modify the external and internal wind pressure (such as doors normally closed but left open under storm conditions) shall be considered. (3)P...

Section General

1.1.1 Scope of ENV 1991 - Eurocode 1 (1)P ENV 1991 provides general principles and actions for the structural design of buildings and civil engineering works including some geotechnical aspects and shall be used in conjunction with ENV 1992-1999. (2) It may also be used as a basis for the design of structures not covered in ENV 1992-1999 and where other materials or other structural design actions are involved. (3) ENV 1991 also covers structural design during execution and structural design...

Section Representation of actions

4.1 Explanation of the wind actions and the response of the structures (11 )P Wind actions are fluctuating with time. They act directly on the external surfaces of enclosed structures and, through porosity of the external surface, also act indirectly on the internal surfaces. They may also directly affect the internal surface of open structures. Pressures act on areas of the surface producing forces normal to the surface for the structure or for individual cladding components. Additionally,...

Vertical walls of rectangular plan buildings

(1) The reference height, ze, for walls of rectangular plan buildings depends on the aspect ratio ft band is given in Figure 10.2.2 for the following three cases (a) Buildings, whose height h is less than b, shall be considered to be one part. (b) Buildings, whose height h is greater than b, but less than 2b, shall be considered to be two parts, comprising a lower part extending upwards from the ground by a height equal to b and an upper part. (c) Buildings, whose height h is greater than 2b,...

Wind forces from pressures

(1) The wind forces acting on a structure or a structural component mav be determined in two ways -as a summation of pressures acting on surfaces provided that the structure or the structural component is not sensitive to dynamic response (cd < 1,2, see section 9). (2)P The global force, Fw, shall be obtained from the following expression Fw Qre,-ce(ze)-cd-q-ABf (6.1) q force coefficient derived from section 10 reference area for q (generally the projected area of the structure normal to the...

Z Flat roofs

(1) Flat roofs are defined within a slope of 4 (2) The roof should be divided into zones as shown in Figure 10.2.4. (3) The reference height ze should be taken as h. (4) Pressure coefficients for each zone are given in Table 10.2.2. (5) For long roofs friction forces should be considered (see 6.2). Table 10.2.2 External pressure coefficients for flat roofs Table 10.2.2 External pressure coefficients for flat roofs

Topography coefficient

1 P The topography coefficient, q z , accounts for the increase of mean wind speed over isolated hills and escarpments not undulating and mountainous regions It is related to the wind velocity at the base of the hili or escarpment It shall be considered for locations closer than half the length of the hill slope from the crest or 1.5 times the height of the cliff. It is defined by q 1 2 s- lt D for 0,05 lt d gt lt 0,3 8.3 1 0,6 s for lt j gt gt 0,3 s factor to be obtained from Figure 8.1 or...

Isbn X

Committees responsible Inside front cover Text of National Application Document Part A Buildings iii Text of National Application Document Part B. Bridges lvii This Draft for Development was prepared by Subcommittee B 525 1 and is the English language version of ENV 1991-2-4 1995 Eurocode 1 Basis of design and actions on structures Part 2.4 Actions on structures Wind actions as published by the European Committee for Standardization CEN . This Draft for Development also includes the United...

National Application Document Part B Bridges

This National Application Document NAD has been prepared by Subcommittee B 525 10. It has been developed from a a textual examination of ENV1991-2-4 1995 b a limited parametric calibration against BS 5400 Part 2 This NAD encompasses wind actions as covered by ENV 1991-2-4. Specific UK requirements relating to loads resulting from densities, self weight and imposed loads ENV 1991-2-1 , fire actions ENV 1991-2-2 , snow loads ENV 1991-2-3 , thermal actions ENV 1991-2-5 , loads and deformations...

Ukv

10.4.2 Pressure coefficients for porous fences 1 Porous fences with solidity ratio y lt 0,8 should be treated as a plane lattice usinq the provisions of 10.10. 10.4.3 Shelter factors for wails and fences 1 When there are other walls or fences upwind that are equal in height or taller than the wall or fence height h, an additional shelter factor can be used with the net pressure coefficients for boundary walls and lattice fences. The value of the shelter factor depends on the spacing between the...

Wind maps and meteorological information

Eurocode European Wind Map

1 P The detailed wind maps and meteorological informations are given in annex A. 2 The basic reference wind velocity of Europe - an informative overlook - is given in Figure 7.2. Figure 7.2 European wind map indicative values only Note 1 The final wind velocities will be defined by the national authorities during the ENV-period in accordance with the format of this Part. 2 Detailed information at the present state is given in annex A

Reference wind velocity

1 P The reference wind velocity, vref, is defined as the 10 min mean wind velocity at 10 m above ground of terrain category II see Table 8.1 having an annual probability of exceedence of 0,02 commonly referred to as having a mean return period of 50 years . 2 P It shall be determined from ref CDIR ' STEM ' calt ' ref.o 7-2 vref 0 basic value o the reference wind velocity as given in annex A Co,R direction factor to be taken as 1,0 unless otherwise specified in annex A c temporary seasonal...

Canopy roofs

1 Canopy roofs are roofs of buildings, which do not have permanent walls, such as petrol station canopies, dutch barns, etc. 2 The degree of blockage under the canopy is shown in Figure 10.3.1. It depends on the solidity ratio tp, which is the ratio of the area of possible obstructions under the canopy divided by the cross area under the canopy, being both areas normal to the wind direction. q gt 0 represents an empty canopy, lt p 1 represents the canopy fully blocked with contents to the down...