Steel Buildings in Europe

Title Appendix A Worked Example: Wind action on a multi-storey building 15 of 18 3 - 36 where: c fr = 0,01 for a smooth surface (steel) q p ( z e ) is the peak velocity pressure at the height z e as given in Table A.1. A fr is the relevant area. The results are summarized in Table A.2 for the different strips of the vertical walls and for the roof. Table A.2 Friction forces – Wind on the gable Strip z e A fr m 2 q p ( z ) kN/m 2 F fr kN 0 10 m 2000 0,72 14,4 10 m 15 m 1000 0,84 8,4 15 m 20 m 1000 0,92 9,2 20 m 25 m 1000 1,00 10,0 25 m 35 m 1700 1,09 18,5 Parapets 35 m 600 1,09 6,5 Roof 35 m 1000 1,09 10,9 120 m h = 35 m Min(2b ; 4h) = 20m W Figure A.6 Friction forces – Wind on the gable 3.6. Wind forces on surfaces 3.6.1. General There are three types of wind forces:  Wind forces resulting from the summation of the external and internal pressure: ( F w,e – F w,i ) / A ref = c s c d q p ( z e ) c pe – q p ( z i ) c pi (in kN/m 2 ) They act normally to the surfaces. They are taken as positive values when they are directed towards the surface and as negative values when they are directed away from the surface.  Friction forces (see Table A.2) F fr = c fr q p ( z e ) A fr (in kN) They act on the external surfaces parallel to the wind direction.