120 likes | 135 Views
Explore the behavior of steel masts using advanced second-order theories and standards like Eurocode 3. Analyze wind effects, guy configurations, and imperfections for structural optimization.
E N D
Janusz Murzewski, Kraków, PRACA ODCIĄGÓW w MASZTACH STALOWYCHBEHAVIOUR OF GUYS OF STEEL MASTS LSCE 2004, Częstochowa
NONLINEAR FIRST ORDER THEORY • Streletski, Moscow,1961 • Petersen, Berlin 1970 • etc. • Old Polish Standard PN-79/B-03204
SIMPLE SECOND-ORDER THEORY • Eurocode 3 Steel design. General rules prEN:1997 • Polish Steel Design Standard PN-90/B-03200
ADVANCED SECOND-ORDER THEORY • European Prestandard prEN 1993-3-1:1997 Towers and masts • New Polish Standard PN-B-03204:2002
SBa - inclined SBa - horizontal LEEWARD GUY at ULS2-nd order parabola Non- analytical curve
c(L) – buckling factor yM(z)+yN(z) - amplification THE ELASTIC SHAFTcontinuous beam free beam-column
Wind patch loading MW=Mm+SMp -global effect Geometrical imperfections Dyi=li/250 - to be amplified UNCERTAIN INNOVATIONSprENV 1993-3-1:1997(who?) PN-B-3204:2002 (A.Cz.)
CONCLUSIONS I • Out-of-plumb f is the main reason of non-linear behaviour • Normal-to-the-shaft component of gravity loads G sinf • Moment of external forces at the bottom hinge M0=0
CONCLUSIONS II • Non-linear behaviour of the windward guy – not important • Deformation of leeward guy needs not to be analysed • The mast at the ULS is statically determined
CONCLUSIONS III • If there are degrees of freedom of the analysis, initial tensions of guys may be optimised • The mass of guys remains constant during deformation • Patch load procedure and geometrical imperfections shall be verified