DS/EN DK NA:2015

Transcription

1 National Annex to Eurocode 1: Actions on structures - Part 1-4: General actions - Wind actions Foreword This national annex (NA) is a reision of DS/EN DK NA: and addendu 1 of , and replaces both docuents on For a transition period until , this National Annex as well as the preious National Annex will be applicable. Technical changes hae been ade in clauses 7..3(4) and 7..10(3), note. Preious ersions of and addenda to this NA as well as an oeriew of all NAs can be found at This NA lays down the conditions for the ipleentation in Denark of DS/EN for construction works in confority with the Danish Building Act or the building legislation. Other parties can put this NA into effect by referring thereto. A National Annex contains national proisions, iz. nationally applicable alues or selected ethods. The Annex ay furtherore gie copleentary, non-contradictory inforation. This NA includes: an oeriew of possible national choices and clauses containing copleentary inforation; national choices; copleentary, non-contradictory inforation.. Foreword Page 1 of 9

2 Oeriew of possible national choices and copleentary inforation The list below identifies the clauses where national choices are possible and the applicable/not applicable inforatie annexes. Furtherore, clauses giing copleentary inforation are identified. Copleentary inforation is gien at the end of this National Annex. Clause Subject National choice 1) Copleentary inforation 1.5() Design assisted by testing and easureents 4.1(1) National cliatic inforation No choice ade 4.(1)P Fundaental alue of the basic wind elocity National choice Note 4.()P Notes Directional factor, seasonal factor and odified National choice 1,, 3 and 5 basic wind elocity 4.3.1(1) Orography factor and ean wind elocity Notes 1 and 4.3.(1) Roughness factor National choice 4.3.() Deterination of terrain roughness 4.3.3(1) Deterination of orography factor 4.3.4(1) Effect of neighbouring structures 4.3.5(1) Effect of closely spaced buildings 4.4(1) Turbulence intensity Note 4.5(1) Characteristic peak elocity pressure and air density Notes 1 and 5.3(5) Lack of correlation National choice 6.1(1) Structural factor 6.3.1(1) Procedure for deterining the dynaic response National choice Note (1) Deterination of displaceents and accelerations National choice 7.1.() Asyetry and torsional effects 7.1.3(1) Effects of ice and snow 7..1(1) Force coefficients for loaded areas between 1 ² Note and 10 ² 7..(1) Reference heights 7..() Pressure coefficients - walls 7..3() Pressure coefficients flat roofs 7..3(4) Pressure coefficients flat roofs National choice 7..4(1) Pressure coefficients onopitch roofs 7..4(3) Pressure coefficients onopitch roofs 7..5(1) Pressure coefficients duopitch roofs Page of 9 Oeriew, national choices and copleentary inforation

3 Clause Subject National choice 1) 7..5(3) Pressure coefficients duopitch roofs 7..6(1) Pressure coefficients hipped roofs 7..6(3) Pressure coefficients hipped roofs 7..7 Pressure coefficients ultispan roofs 7..8(1) Pressure coefficients aulted roofs and does 7..9() Internal pressure opening ratio 7..9(6) Note Internal pressure without a doinant face 7..10(3) Wind pressure on walls or roofs with ore than one skin 7..10(3) Wind pressure on walls or roofs with ore than National choice Note one skin 7.3(6) Canopy roofs onopitch roofs 7.4.1(1) Free-standing walls and parapets 7.4.3() Horizontal eccentricity for signboards 7.6(1) Effects of rounded corners 7.7(1) Force coefficients for priss with sharp edged sections 7.8(1) Force coefficients for priss with regular polygonal section (>4) 7.9.() Force coefficient surface roughness, k, for worn surfaces Force coefficients for ertical cylinders in a row arrangeent National choice Table (1) Force coefficients for spheres 7.11(1) Reduction factors for scaffolding Note 7.13(1) Reduction factors for free-end flow for cylinders or priss 7.13() Slenderness and reduction factors 8.1(1) Notes 1 and Wind actions on bridges Not releant for building struc- 8.1(4) Substitute alue for the fundaental alue of the basic wind elocity 8.1(5) Substitute alue for the fundaental alue of the basic wind elocity tures Not releant for Not releant for Page 3 of 9 Oeriew, national choices and copleentary inforation Copleentary inforation Copleentary inforation

4 Clause Subject National choice 1) Page 4 of 9 Oeriew, national choices and copleentary inforation Copleentary inforation 8.(1) Dynaic response procedure for bridges 8.3(1) Force coefficients for wind force on parapets etc. on bridges Not releant for Not releant for 8.3.1() Reduction factor for wind actions on bridges Not releant for 8.3.(1) Force coefficient for wind actions on bridges Not releant for 8.3.3(1) Force coefficient for wind actions on bridges Not releant for 8.3.4(1) Force coefficient for wind actions on bridges Not releant for 8.4.(1) Notes 1 and Wind effects on piers Not releant for A.(1) Inhoogeneous terrain National choice E.1.3.3(1) Air density E.1.5.1(1) Notes Choice between procedures 1 and National choice 1 and E.1.5.1(3) Choice between procedures 1 and National choice E (1) Nuber of load cycles National choice E.1.5.3() Air density E.1.5.3(4) Influence of turbulence intensity National choice E.1.5.3(6) Peak factor E.3() Stability paraeter No choice ade 1) : The recoendation in the Eurocode is followed. National choice: A national choice has been ade. Not releant for : See the National Annexes published by the Danish Road Directorate and Banedanark. No choice ade: The Eurocode does not recoend alues or ethods, but allows the option of deterining national alues or ethods.

5 National choices 4. (1)P NOTE Fundaental alue of the basic wind elocity The fundaental alue of the basic wind elocity, b,0, is taken as 4 /s eerywhere in Denark apart fro a border zone in Jutland with localities less than 5 k fro the North Sea and Ringkøbing Fjord. The fundaental alue of the basic wind elocity in the border zone is taken as 7 /s at the coastline decreasing linearly to 4 /s at the other edge of the border zone. For the deterination of the border zone, local orographic conditions, e.g. the inlets of Western Jutland, shall be taken into account. 4. ()P NOTES 1,, 3 and 5 Directional factor and seasonal factor and odified basic wind elocity The odified basic wind elocity is not changed. The directional factor squared, c dir, is gien in table 1a, where the wind direction denotes the idpoint of the 30 sector fro where the wind coes. The directional factor should be applied together with the terrain ealuation to deterine the characteristic wind elocity fro the wind direction considered, if the direction conditions can be assued to exist as long as the structure. Table 1a DK NA - Directional factor squared c dir Wind direction N 0 NNE 30 ENE 60 E 90 ESE 10 SSE 150 0,8 0,8 0,8 0,8 0,8 0,8 c dir S SSW WSW Wind direction ,8 0,8 0,9 1,0 1,0 0,9 c dir W WNW The seasonal factor squared is gien in Table 1b DK NA. NNW Table 1b DK NA - Seasonal factor squared c season Month s. c season Jan Feb Mar Apr May June July Aug Sep Oct No Dec 1,0 1,0 0,9 0,9 0,8 0,7 0,7 0,7 0,8 0,9 0,9 1, (1) Terrain roughness The recoended procedure for deterining the roughness factor at height z is gien by Expression (4.4). The following is added at the end of the NOTE after sufficiently, see () Costal areas exposed to onshore wind are assigned to terrain category I for the wind directions in question In Table 4.1, terrain category I is extended to include and costal area exposed to the open sea. National choices Page 5 of 9

6 5.3 (5) Lack of correlation The effect of the lack of correlation of wind pressures between the windward and leeward sides ay be taken into account when deterining the wind force (1) Note 3 Procedure for deterining the dynaic response The procedure gien in Annex C is applied. 6.3.(1) Deterination of displaceents and accelerations The procedure gien in Annex C is applied. 7..3(4) Pressure coefficients flat roofs The pressure coefficient for zone I of -0, is changed to -0, (3), Note, Wind pressure on walls with ore than one skin In the first indent ("-"), the following is added after the last sentence: For zones denoted "A" in Figure 7.5, the pressure coefficient stated for the pereable outer skin ay underestiate the wind force. This wind force is not underestiated if the pressure coefficient is taken as -0, Table 7.14, Force coefficients for ertical cylinders in a row arrangeent Table 7.14 ay underestiate the wind force for a/b <,5 A. (1) Inhoogeneous terrain Procedure 1 is applied. For procedure 1, category 0 is replaced by category I and categories I to III is replaced by "categories II and III". E (1), Notes 1 and, Choice between procedures 1 and Procedure is applied. En1.5.1 (3), Choice between procedures 1 and Procedure is applied. E (1),, Nuber of load cycles - fatigue actions For structures where the characteristic axiu displaceent deterined in E of EN :005 is less than approx.10% of the cross-wind diensions, the fatigue actions ay be deterined by eans of E of EN :005 using the constants C and K as stated below. c a National choices Page 6 of 9

7 The dependence of the constant C of the wind elocity ratio ean wind elocity and crit c /, where is the 10 inute crit, i, i is the resonance wind elocity, is deterined approxiately by: C c C c ( Table E.6) crit, i 3/ 1 1 crit, i / exp B C c ( Table E.6) is gien in Table E.6 in EN , and B can approxiately be taken as B = 0,1. The 10 inute ean wind elocity and the resonance wind elocity height aboe ground with the largest oeent of the structure. crit, i are deterined at the The oeent of the structure is not underestiated if the dependence of the aerodynaic daping constant K a of the wind elocity ratio / crit, i and the turbulence intensity I is deterined by the following siplified and approxiated expression: K a K a, ax h( I ) g crit, i The function h I ) is defined in E (4) below. The function g assues its axiu alue equal ( to 1 for and is taken to decrease linearly fro 1 to 0 for crit, i. g is taken as 0 for and i. crit, i crit, i crit, The frequency of ean wind elocities up to approx /s can be deterined on the basis of the European wind atlas, see Troen, I.; Petersen, B. & Lundtang, E., 1989, European Wind atlas, Risø, Roskilde. For wind oer a terrain of a roughness length between approx. 0,01 and approx. 0,05, the frequencies of the different turbulence intensities can be ealuated on the basis of a noral distribution using the ean alue gien in 4.4 (1) in EN and a deiation decreasing gradually fro approx. 0,06 at ean wind elocities saller than approx. 5 /s to approx. 0,03 for ean wind elocities of approx. 10 /s. The probability ass of the noral distribution for negatie arguents should be taken here to correspond to a turbulence intensity of 0. For fatigue analyses based on the specifications stated aboe, the coefficient of ariation of the fatigue loads should be taken as 30% when the partial factor is deterined, see the National Annex to EN E (4) Influence of turbulence intensity The effect of rhythic ortex shedding depends on the turbulence intensity of the wind. For 10 inute wind elocities larger than approx.15 /s, the turbulence intensity of the wind is deterined using National choices Page 7 of 9

8 4.4 (1) in EN :005. For 10 inute wind elocities saller than approx. 10 /s, consideration should be gien to rhythic ortex shedding in turbulence free wind which occurs under certain, relatiely rare eteorological conditions. The oeent of the structure is not underestiated if the dependence of the aerodynaic daping constant K a of the turbulence intensity I is deterined by eans of the following siplified and approxiated expression: K a ( I ) K ax h( I a, ) where K a, ax is gien in Table E.6 in EN :005. The function h is deterined fro h( I ) 1 3I for 0 I 0, 5 og h ( I ) 0, 5 for I > 0,5. The turbulence intensity I is deterined at the height aboe ground with the largest oeent of the structure. National choices Page 8 of 9

9 Copleentary, non-contradictory inforation 7..9(6) Note, Internal pressure without a doinant face The following is added at the end of the note after "... ore onerous of +0, and -0,3": In this case partitions can be taken as a wind action corresponding to the pressure coefficient of 0,4 due to pressure ariations in the roos separated by the partitions. Literature Troen, I.; Petersen, B. & Lundtang, E., 1989, European Wind Atlas, Risø, Roskilde. Copleentary inforation Page 9 of 9