Eurocode 3 Part 1-5 (EN ) Plated structural elements

En presentation över ämnet: "Eurocode 3 Part 1-5 (EN ) Plated structural elements"— Presentationens avskrift:

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

2 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

3 Shear lag beff =  b Conference Oslo

4 Shear lag Conference Oslo

5 Conference Oslo

6 Shear lag At Ultimate Limit State * =  Conference Oslo

7 Plate buckling, classical theory of stability
x y a b Conference Oslo

8 Post buckling behaviour of plate with initial imperfections
s/scr w t wo Conference Oslo

9 Influence of boundary conditions
a) b) Conference Oslo

10 Effective width, von Karman
fy bef/2 b Conference Oslo

11 Test results plate buckling
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12 Residual stresses Conference Oslo

13 Flange buckling Conference Oslo

14 Flange buckling, post buckling behaviour
Stress distribution for sm = 2scr Conference Oslo

15 Test results flange buckling
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16 Effective cross section for centric compression
bw,eff = rbw r = 1, if l ≤ 0,67 if l > 0,67 bf,eff bf tf tw bw,eff/2 bw Conference Oslo

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

18 Cross section classes for bending in EC3
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19 Conference Oslo

20 Web in class 3 Conference Oslo

21 Effective cross section for web plate
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22 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

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

24 s1 s2 a b Second moment of area of the whole stiffened plate;
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25 One stiffener Ncr is the largest of: Conference Oslo

26 Column type buckling Buckling of the stiffened plate with longitudinal edges assumed to be unsupported. Conference Oslo

27 Reduction factor cc = 0,34 for closed stiffener
= 0,49 for open stiffener Conference Oslo

28 Interpolation and effective area
Final effective area Conference Oslo

29 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 Conference Oslo

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

31 Conference Oslo

32 Conference Oslo

33 Conference Oslo

34 Konventionell beräkning ger scr=624 MPa
scr=2,508x300=752 MPa Konventionell beräkning ger scr=624 MPa Conference Oslo

35 Avser livets kant, mitt för avstyvningen fås
scr=4,857x300=1457 MPa Avser livets kant, mitt för avstyvningen fås scr = 728 MPa Conference Oslo

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

37 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 Torn och master Del Skorstenar Del 4-1 Tankar Del 4-2 Silos Del 4-3 Rörledningar Del 5 Pålar och sponter Del 6 Kranbanor Conference Oslo

38 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

39 Shear buckling Conference Oslo

40 Resistance to shear buckling
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41 Model for shear buckling resistance
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42 Resistance according to Eurocode 3-1-5
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43 Rigid end post The bearing stiffener should be designed for the support reaction. The additional stiffener should fulfil Conference Oslo

44 Contribution from flanges
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45 Patch loading Conference Oslo

46 Stress distribution under concentrated load
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47 Critical force Conference Oslo

48 Yield force Conference Oslo

49 Resistance to patch load
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50 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

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

52 Interaction M-V Conference Oslo

53 Interaction patch load and bending
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54 Flange induced buckling
K=0,55 elastic resistance K=0,40 plastic resistance K=0,30 plastic rotation Conference Oslo