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...

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

D.4.7 Effect of parapets on pitched roofs D.4.7.1 The effects of parapets should be taken into account to determine pressure coefficients on pitched roofs. Owing to the way that parapets around roofs change the positive pressures expected on upwind pitches with large positive pitch angles to suction, neglecting their effect is not always conservative. Pressures on the parapet walls should be determined in accordance with 10.4.1 of ENV 1991-2-4 1995 for free-standing walls and, for the downwind...

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...

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 ,...

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

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...