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)

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

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 ,...

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...

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...

National Application Document Part A Buildings

6399 Terrain Category

This National Application Document NAD has been prepared by Subcommittee B 525 1. It has been developed from a a textual examination of ENV 1991-2-4 b a limited parametric calibration against BS 6399 Part 2 and CP 3 Chapter V 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 ,...

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...

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...