Eurocode 3 Part 1-5 (EN 1993-1-5) Plated structural elements Professor Bernt Johansson Steel Structures Luleå University of Technology Conference Oslo 2007-05-09

Eurocode 3-1-5 1 Introduction 2 Basis of design and modelling 3 Shear lag in member design 4 Plate buckling effects due to direct stress 5 Resistance to shear 6 Resistance to transverse forces 7 Interaction 8 Flange induced buckling 9 Stiffeners and detailing 10 Reduced stress method Conference Oslo 2007-05-09

Shear lag beff =  b Conference Oslo 2007-05-09

Shear lag Conference Oslo 2007-05-09

Conference Oslo 2007-05-09

Shear lag At Ultimate Limit State * =  Conference Oslo 2007-05-09

Plate buckling, classical theory of stability x y a b Conference Oslo 2007-05-09

Post buckling behaviour of plate with initial imperfections s/scr w t wo Conference Oslo 2007-05-09

Influence of boundary conditions a) b) Conference Oslo 2007-05-09

Effective width, von Karman fy bef/2 b Conference Oslo 2007-05-09

Test results plate buckling Conference Oslo 2007-05-09

Residual stresses Conference Oslo 2007-05-09

Flange buckling Conference Oslo 2007-05-09

Flange buckling, post buckling behaviour Stress distribution for sm = 2scr Conference Oslo 2007-05-09

Test results flange buckling Conference Oslo 2007-05-09

Effective cross section for centric compression bw,eff = rbw r = 1,0 if l ≤ 0,67 if l > 0,67 bf,eff bf tf tw bw,eff/2 bw Conference Oslo 2007-05-09

Effective cross section for centric compression bf,eff = rbf r = 1,0 om l ≤ 0,75 om l > 0,75 bf,eff bf tf tw bw,eff/2 bw Conference Oslo 2007-05-09

Cross section classes for bending in EC3 Conference Oslo 2007-05-09

Conference Oslo 2007-05-09

Web in class 3 Conference Oslo 2007-05-09

Effective cross section for web plate Conference Oslo 2007-05-09

Plates with longitudinal stiffeners Determine effective area Ac,ef,loc for buckling of subpanels Determine reduction factor r for buckling of the stiffened plate Determine reduction factor cc for column like buckling of the stiffened panel Interpolate between r and cc to get final reduction factor rc. Conference Oslo 2007-05-09

Plates with longitudinal stiffeners scr,p is the critical stress for plate buckling according to orthotropic plate theory. Conference Oslo 2007-05-09

s1 s2 a b Second moment of area of the whole stiffened plate; Conference Oslo 2007-05-09

One stiffener Ncr is the largest of: Conference Oslo 2007-05-09

Column type buckling Buckling of the stiffened plate with longitudinal edges assumed to be unsupported. Conference Oslo 2007-05-09

Reduction factor cc = 0,34 for closed stiffener = 0,49 for open stiffener Conference Oslo 2007-05-09

Interpolation and effective area Final effective area Conference Oslo 2007-05-09

Software EBPlate A software for calculating critical stresses for stiffened or unstiffened plates created by CTICM is available free of charge on the Internet at the URL http://www.steelbizfrance.com/file/recfile.asp?idrub=58 Conference Oslo 2007-05-09

Reduktion för belastad area m2 Röd kurva EK 1-1-1 Svarta kurvor BKR Reduktion enligt EK 1-1-1 avser karakteristisk last och gäller endast för pelare och väggar medan BKR:s reduktion gäller alla konstruktionsdelar och även vanlig last. Conference Oslo 2007-05-09

Conference Oslo 2007-05-09

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Conference Oslo 2007-05-09

Konventionell beräkning ger scr=624 MPa scr=2,508x300=752 MPa Konventionell beräkning ger scr=624 MPa Conference Oslo 2007-05-09

Avser livets kant, mitt för avstyvningen fås scr=4,857x300=1457 MPa Avser livets kant, mitt för avstyvningen fås scr = 728 MPa Conference Oslo 2007-05-09

Eurokod 2 Del 1-1 Allmänna regler och byggnader Del 1-2 Brand Del 2 Broar Del 3 Behållare och barriärer Conference Oslo 2007-05-09

Eurokod 3 tcr = 0,6764x100 = 67,6 MPa Konventionell beräkning ger tcr = 62,8 MPa Allmänna delar Tillämpningsdelar Del 1-1 Allmänna regler och byggnader Del 1-2 Brand Del 1-3 Tunnplåtskonstruktioner Del 1-4 Rostfritt stål Del 1-5 Plåtbalkar Del 1-6 Skalkonstruktioner Del 1-7 Transversalbelastad plåt Del 1-8 Förband och knutpunkter Del 1-9 Utmattning Del 1-10 Sprödbrott och skiktbristning Del 1-11 Stålkablar Del 1-12 Utvidgning till S700 Del 2 Broar Del 3-1 Torn och master Del 3-2 Skorstenar Del 4-1 Tankar Del 4-2 Silos Del 4-3 Rörledningar Del 5 Pålar och sponter Del 6 Kranbanor Conference Oslo 2007-05-09

Yield resistance to shear 0,5 10 20 gG/fv t fv g 0,82 h = 1,2 for grades up to and including S460 h = 1 for higher grades Conference Oslo 2007-05-09

Shear buckling Conference Oslo 2007-05-09

Resistance to shear buckling Conference Oslo 2007-05-09

Model for shear buckling resistance Conference Oslo 2007-05-09

Resistance according to Eurocode 3-1-5 Conference Oslo 2007-05-09

Rigid end post The bearing stiffener should be designed for the support reaction. The additional stiffener should fulfil Conference Oslo 2007-05-09

Contribution from flanges Conference Oslo 2007-05-09

Patch loading Conference Oslo 2007-05-09

Stress distribution under concentrated load Conference Oslo 2007-05-09

Critical force Conference Oslo 2007-05-09

Yield force Conference Oslo 2007-05-09

Resistance to patch load Conference Oslo 2007-05-09

Interaction If two or more cross sectional resultants act simultaneously they interact in using the resistance. Often the interaction is weak and it is neglected. Conference Oslo 2007-05-09

Bending and shear According to Eurocode 3-1-5 for an I-girder ty h fy According to Eurocode 3-1-5 for an I-girder Conference Oslo 2007-05-09

Interaction M-V Conference Oslo 2007-05-09

Interaction patch load and bending Conference Oslo 2007-05-09

Flange induced buckling K=0,55 elastic resistance K=0,40 plastic resistance K=0,30 plastic rotation Conference Oslo 2007-05-09