Presentation laddar. Vänta.

Presentation laddar. Vänta.

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

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En presentation över ämnet: "Conference Oslo 2007-05-09 1 Eurocode 3 Part 1-5 (EN 1993-1-5) Plated structural elements Professor Bernt Johansson Steel Structures Luleå University of."— Presentationens avskrift:

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

2 Conference Oslo 2007-05-09 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

3 Conference Oslo 2007-05-09 3 Shear lag b eff =  b

4 Conference Oslo 2007-05-09 4 Shear lag

5 Conference Oslo 2007-05-09 5

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

7 Conference Oslo 2007-05-09 7 Plate buckling, classical theory of stability x y a b

8 Conference Oslo 2007-05-09 8 Post buckling behaviour of plate with initial imperfections  /  cr w t w o t

9 Conference Oslo 2007-05-09 9 Influence of boundary conditions a)b)

10 Conference Oslo 2007-05-09 10 Effective width, von Karman fyfy b ef /2 b

11 Conference Oslo 2007-05-09 11 Test results plate buckling

12 Conference Oslo 2007-05-09 12 Residual stresses

13 Conference Oslo 2007-05-09 13 Flange buckling

14 Conference Oslo 2007-05-09 14 Flange buckling, post buckling behaviour Stress distribution for  m = 2  cr

15 Conference Oslo 2007-05-09 15 Test results flange buckling

16 Conference Oslo 2007-05-09 16 Effective cross section for centric compression b f,eff bfbf tftf twtw b w, eff / 2 bwbw b w,eff =  b w  = 1,0 if ≤ 0,67 if > 0,67

17 Conference Oslo 2007-05-09 17 Effective cross section for centric compression b f,eff bfbf tftf twtw b w, eff / 2 bwbw b f,eff =  b f  = 1,0 om ≤ 0,75 om > 0,75

18 Conference Oslo 2007-05-09 18 Cross section classes for bending in EC3

19 Conference Oslo 2007-05-09 19

20 Conference Oslo 2007-05-09 20 Web in class 3

21 Conference Oslo 2007-05-09 21 Effective cross section for web plate

22 Conference Oslo 2007-05-09 22 Plates with longitudinal stiffeners Determine effective area A c,ef,loc for buckling of subpanels Determine reduction factor  for buckling of the stiffened plate Determine reduction factor  c for column like buckling of the stiffened panel Interpolate between  and  c to get final reduction factor  c.

23 Conference Oslo 2007-05-09 23 Plates with longitudinal stiffeners  cr,p is the critical stress for plate buckling according to orthotropic plate theory.

24 Conference Oslo 2007-05-09 24 Second moment of area of the whole stiffened plate; a b 11 22

25 Conference Oslo 2007-05-09 25 One stiffener N cr is the largest of:

26 Conference Oslo 2007-05-09 26 Column type buckling Buckling of the stiffened plate with longitudinal edges assumed to be unsupported.

27 Conference Oslo 2007-05-09 27  = 0,34 for closed stiffener  = 0,49 for open stiffener Reduction factor  c

28 Conference Oslo 2007-05-09 28 Interpolation and effective area Final effective area

29 Conference Oslo 2007-05-09 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 http://www.steelbizfrance.com/file/recfile.asp?idrub=58

30 Conference Oslo 2007-05-09 30 Reduktion för belastad area 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. m2m2

31 Conference Oslo 2007-05-09 31

32 Conference Oslo 2007-05-09 32

33 Conference Oslo 2007-05-09 33

34 Conference Oslo 2007-05-09 34  cr =2,508x300=752 MPa Konventionell beräkning ger  cr =624 MPa

35 Conference Oslo 2007-05-09 35  cr =4,857x300=1457 MPa Avser livets kant, mitt för avstyvningen fås  cr = 728 MPa

36 Conference Oslo 2007-05-09 36 Eurokod 2 Del 1-1 Allmänna regler och byggnader Del 1-2 Brand Del 2 Broar Del 3 Behållare och barriärer

37 Conference Oslo 2007-05-09 37 Eurokod 3 Allmänna delarTillämpningsdelar 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 4-1Tankar Del 4-2Silos Del 4-3Rörledningar Del 5Pålar och sponter Del 6 Kranbanor  cr = 0,6764x100 = 67,6 MPa Konventionell beräkning ger  cr = 62,8 MPa

38 Conference Oslo 2007-05-09 38 Yield resistance to shear 0,5 0 01020 G/fvG/fv fv fv   0,82  = 1,2 for grades up to and including S460  = 1 for higher grades

39 Conference Oslo 2007-05-09 39 Shear buckling

40 Conference Oslo 2007-05-09 40 Resistance to shear buckling

41 Conference Oslo 2007-05-09 41 Model for shear buckling resistance

42 Conference Oslo 2007-05-09 42 Resistance according to Eurocode 3-1-5

43 Conference Oslo 2007-05-09 43 Rigid end post The bearing stiffener should be designed for the support reaction. The additional stiffener should fulfil

44 Conference Oslo 2007-05-09 44 Contribution from flanges

45 Conference Oslo 2007-05-09 45 Patch loading

46 Conference Oslo 2007-05-09 46 Stress distribution under concentrated load

47 Conference Oslo 2007-05-09 47 Critical force

48 Conference Oslo 2007-05-09 48 Yield force

49 Conference Oslo 2007-05-09 49 Resistance to patch load

50 Conference Oslo 2007-05-09 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.

51 Conference Oslo 2007-05-09 51 Bending and shear yy h fyfy fyfy According to Eurocode 3-1-5 for an I-girder

52 Conference Oslo 2007-05-09 52 Interaction M-V

53 Conference Oslo 2007-05-09 53 Interaction patch load and bending

54 Conference Oslo 2007-05-09 54 Flange induced buckling K=0,55 elastic resistance K=0,40 plastic resistance K=0,30 plastic rotation


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