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)

Crest

Figure 8.2 Factor s for hills and ridges Figure 8.2 Factor s for hills and ridges (1)P The exposure coefficient, ce(z), takes into account the effects of terrain roughness, topography and height above ground on the mean wind speed and turbulence. It is defined by (z) c2r (z) c (z) 1 + 2g (z) (8.4) (z) turbulence intensity, given by (2)P For codification purposes it has been assumed that the quasi-static gust load is determined from kj terrain factor as defined in 8.2 ctfz) roughness coefficient...

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...

Info

(4) Values for the temporary factor, c , are given in Table A5. These values allow the assement of wind loads in sub-annual periods for temporary structures or structures in a temporary condition during construction. Note that using these factors results in the entire design annual risk being transferred to the sub-annual period and the user should consider whether a 0,02 risk in the sub-annual period is still appropriate. Note also that delays in construction, etc. in the summer period may...

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...

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 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...

Internal Pressure On Open Sided Building

D. 1.6.6 Internal pressure coefficients cp,iI0 for open-sided buildings are given in table D.4 according to the form of the building. The relevant diagonal dimension a for use with these coefficients is the diagonal dimension of the open face. In table D.4, a wind direction of 0 0 corresponds to wind normal and blowing into the open face, or the longer face in the case of two or three open faces. D. 1.6.7 For buildings with two opposite open faces, wind skewed at about 0 45, to the axis of the...

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...