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)

Vortes Shedding Force Stated In Eurcode

Figure C.1 Strouhal number (St) for rectangular cross sections with sharp corners (1) The effect of vortex excited vibrations can be calculated from the inertia force per unit length Fy normal to the wind direction at point j of the structure, determined from Fu m ' (2 * * < & i.y.j max yF (C.3) niy natural frequency of crosswind mode i. Approximations for rc are given in C.4.2 i.yj crosswind mode shape i ratio of the dynamic deflection of the structure at point j to that of the antinode...

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...

Code Ics Eurododes

No copying without bsi permission except as permitted by copyright law ekaflf Committees responsible for this Draft for Development The preparation of this Draft for Development was entrusted by Technical Committee B 525, Building and civil engineering structures, to Subcommittee B 525 1, Actions Ooadings) and basis of design, upon which the following bodies were represented British Constructional Steelwork Association British Iron and Steel Producers' Association British Masonry Society...

Info

The mode shape, < J> (z), has been taken from C.4.3. The parameters, n,m, are defined in equation (C.7) and in Figure C.3 (1) The mode shape factor Kis given by (z) crosswind mode shape i (see C.4.3) length of the structure between two nods (see Figure C.3) J* mple structures vibrating in the fundamental crosswind mode the mode shape factor is given in Table C.4. mit dbyUmber f StreSS 0X0168 Vcaused bV vortex excited oscillation may be esti- natural frequency of crosswind mode i in Hz ,...

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...

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.

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...

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

Design Values Actions Eurocode

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...

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...

Roughness coefficient

1 P The roughness coefficient, cr z , accounts for the variability of mean wind velocity at the site of the structure due to - the height above ground level - the roughness of the terrain depending on the wind direction. 2 P The roughness coefficient at height z is defined by the logarithmic profile q z kT In zfzo for zmin lt z lt 200m 8.2 kT terrain factor Zq roughness length z minimum height These parameters depend on the terrain category as given in Table 8.1. 3 At heights more than 200 m...

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...