Design rules for bridges in Eurocode 3

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1 Design rules for bridges in Eurocode 3 Gerhard Sedlacek Christian üller

2 Survey of the Eurocodes EN 1991 EN 1990 Eurocode: Basis of Design EN 1992 to EN 1996 Eurocode 1: Actions on Structures Eurocode 2: Concrete structures 1-1 Self weight Eurocode 3: Steel structures 1-2 Fire Actions Eurocode 4: Composite structures 1-3 Snow Eurocode 5: Timber structure 1-4 Wind Eurocode 6: asonry structures 1-5 Thermal Actions 1-6 Construction Loads 1-7 Accidential Actions 2 Traffic on bridges 3 Loads from cranes 4 Silo loads EN 1997 and EN 1998 Eurocode 7: Geotechnical Design Eurocode 8: Design in seismic areas Eurocode 9: EN 1999 Aluminium structures 2

1-4 Wind Eurocode 6: asonry structures 1-5 Thermal Actions 1-6 Construction Loads 1-7 Accidential Actions 2 Traffic on bridges 3 Loads from

3 Cross section of a box girder bridge with an orthotropic deck 3

4 European unified and nationally determinable part of the load models Traffic load Ed Action effect E d = Ed Rd Resistance R d = Rd European unified geometrical loading model with amplitudes E k E d = g F1 E k1 + y 0 g F2 E k2 National choices g F, y 0, g 4

= Rd European unified geometrical loading model with amplitudes

5 Single span bridge K210 and tied arch bridge K138 K 210 K 138 5

6 Safety indices b for various structural elements of the reference bridge K210 and K138 6

7 Determination of g Q by comparing the results of probabilistic design of single span and continuous span bridges and design with EC 1-2 load model Probabilistic design EC 1 - Part 2 Load odel W required L Q Qd = f y W g requ - G g G where g g G = 1,10 = 1,35 Qd = g Q L Q g Q = Qd L Q 7

model Probabilistic design EC 1 - Part 2 Load odel W required L Q Qd =

Fatigue load model specified in EN 1991 Number of expected trucks per year for a single lane Traffic Category 1: 2-Lane Highways with a high rate of heavy vehicles 2: Highways and roads with a medium

8 Fatigue load model specified in EN 1991 Number of expected trucks per year for a single lane Traffic Category 1: 2-Lane Highways with a high rate of heavy vehicles 2: Highways and roads with a medium rate of heavy vehicles 3: ain roads with a low rate of heavy vehicles 4: Country roads with a low rate of heavy vehicles Number of heavy vehicles N / a 0, / a 0, / a 0, / a 8

rate of heavy vehicles 3: ain roads with a low rate of heavy vehicles 4: Country roads with a low

9 Concept for fatigue assessment with equivalent constant amplitude stress ranges g Ff j fat l Ds max Ds c / g f safety factor for fatigue strength reference fatigue strength at cycles damage equivalent impact factor damage equivalence factor representing the spectrum maximum stress range from EC 1-2 loadmodel crack size a critical crack size a crit safety factor for fatigue load g Ff = 1,00 g f = 1,00 1,15 for damage tolerance g f = 1,25 1,35 for safe life method detectable crack size a 0 inspection interval time 9

the spectrum maximum stress range from EC 1-2 loadmodel crack size a critical crack size a crit safety factor for fatigue load g Ff

10 Fatigue details welded attachments and stiffeners 10

11 oment of Resistance W/L [cm 2 m/m] Required moment of inertia from ULS and fatigue design for detail category 71 α = 1,0 ULS α = 0, 8 Fatigue Span L [m] 11

12 Joint for hanger Alternatives for joints of hangers: optimised joint: continuously increasing stiffness (K90) low curvature from bending end of hanger with hole and inclined cut low stresses at end of hanger for K50 ratio of inclined cut and connecting plate avoiding of stress peak at end of hanger 12

hanger with hole and inclined cut low stresses at end of hanger for K50

13 Hanger connection for arch bridges

14 Standard orthotropic steel deck with continuous stringers with cope holes in the web of the cross beam 14

15 distance between cross girders a [m] Steel bridges serviceability limit state Requirements for the minimum stiffness of stringers depending on the distance between crossbeams 5 4 A B second moment of area I B of the stringers including deckplate [m 4 ] 1,20m 1 Condition for curve A 2 I B 1 heavy traffic lane 2 web of main girder or longitudinal girder 15

5000 10000 15000 20000 second moment of area I B of the stringers including deckplate [m 4 ]

16 Structural detailing for deck plate connection of deck plate to troughs Verbindung Längsrippe - Deckblech HV HV HV design life load model 4 without layer < 10 years asphaltic sealing years PmB 45 thermosetting resin years PmB 25 16

300 design life load model 4 without layer < 10 years asphaltic

17 Structural detailing for cross beams h T > 0,15 h T h QTr t Steg t Ltrough = 6 mm t web = mm; verification of net web section requirded h crossbeam 700 mm 17

= 6 mm t web = 10-16 mm; verification of

18 transverse edge stiffened panel width Plate buckling Verification to web breathing Definition of a plated element longitudinal edge b21 x subpanel bg a 1 a 2 a 3 a 4 y a G stiffened panel length 18

Standard system for steel structures EN 1090 Part 1 Delivery Conditions for prefabricated steel components hen product standards for steel materials, semi- finished products etc.

19 Standard system for steel structures EN 1090 Part 1 Delivery Conditions for prefabricated steel components hen product standards for steel materials, semi- finished products etc. Eurocode: EN 1990 Basis of structural design Eurocode 1: EN 1991 Actions on structures Eurocode 3: EN 1993 Design rules for steel structures EN 1090 Part 2 Execution of steel structures HSS up to S

Eurocode: EN 1990 Basis of structural design Eurocode 1: EN 1991 Actions on structures Eurocode

20 Design rules for steel bridges in Eurocode 3 EN 1993-Part 1-1 General rules 1-5 Plate buckling 1-8 Connections 1-9 Fatigue 1-10 Choice of material 1-11 Rope structures EN 1993-Part 2 Steel bridges Annex A Requirements for bearings Annex B Requirements for expansion joints Annex C Recommendations for orthotropic plates 20

structures EN 1993-Part 2 Steel bridges Annex A Requirements for bearings Annex

21 Basic features of design rules for bridges Limit State Concept ULS E d R d SLS E d C d Fatigue Ds E Ds c Choice of material based on fracture mechanics (EN ) Stability of members and plates Single l-value for combined actions, FE-methods (EN ) (EN ) Fatigue assessments unless recommended details are used (EN ) (EN ) 21

22 Choice of material Assumption for a 0 a 0 a d a d = a 0 f Ds c fatigue loading initial crack design crack Safety assessment based on fracture mechanics K appl,d K mat,d K mat,d (T 27J, T Ed ) K appl,d (member shape, a d, y 1 s Ed ) 22

23 Design situation for choice of material in EN aterial toughness J, CTOD, K B 1 JC-, KIC- domain J i, CTODi A 1 s R, R T min T i T room T B 2 Action effect s E, E E ( gg G K + gg Q K ) plastic behaviour R E (G K + Q K ) R el B 3 d R g R = g pl el = curves of equal densities A 2 E (G K + y 1 Q K ) E (G K + y 2 Q K ) E (G ) K f y elastic behaviour A 3 sed = s (G K + y1 Q K ) T min T room T y 23

24 Safety assessment based on temperature K* appl,d K mat,d Transformation T Ed T Rd Assessment scheme Action side T Ed T Rd Resistance. T Ed = DT min + DT r + DT s + DT R [DT + DT pl ] T Rd = T 100 lowest air temperature in combination with s Ed : T min = -25 C radiation loss: DT r = - 5 C influence of stress, crack imperfection and member shape and dimension: DT s K k = -52 ln R6 additive safety element: beff appl DT R = +7 C (with b = 3,8) [C] Influence of material toughness T 100 = T 27J 18 [ C] 24

25 Choice of material to EN

26 Example: Thick plates for the composite Elbebridge Vockerode (EN ) Cross section Bridge system and construction Plate thickness for S355 J2G3 Support Span Support Upper chord Bottom plates Construction at supports 125,28 26

27 Choice of material to EN Olympic stadium in Berlin 27

28 Bridge St. Kilian 28

29 Bridge St. Kilian 29

30 Cast node for the bridge St. Kilian 30

31 Cast node for the bridge St. Kilian 31

32 Common design rules for column, lateral torsional, plate and shell buckling E d E d E d b r E d 1,20 1,00 0,80 0,60 l k column buckling lat. tors. buckl. plate buckling shell buckling a 0 a b c d s k ult crit, ke d = Rk R k ult, l = = E = R R d E d crit EN EN ,20 1,00 0,80 0,60 a b c d crit p [-] E d /2 1,2 1,0 0,8 0,6 a k crit EN a 0 b = l 1,2 1,0 0,8 χ 0,6 E d EN t E d 0,40 0,40 0,4 0,4 0,20 0,20 0,2 0,2 0,00 0 0,5 1 1,5 _ 2 2,5 3 l 0,00 0 0,5 1 1,5 _ 2 2,5 3 l E R g k d 1 0,0 _ 0,0 0,5 1,0 l 1,5 2,0 2,5 3,0 p [-] g ult, k 0,0 0,0 0,5 1,0 1,5 2,0 2,5 3,0 λ 32

33 odelling of plate buckling F f y s limit f y f y yield plateau s limit R ult R el s limit f y s limit f y effective cross section gross cross section limit y f y 33

34 Imperfections for members with various boundary conditions N Ed N Ed N Ed EI a 1 C N Ed x x ini e = e = e 0d 0d x sin 1 NEd N 1- N Ed crit x sin ini e = e = e 0d 0d 2 crit crit,max NEd N 1- EI Ed 2 crit crit crit crit,max 34

35 echanical background of column- and lateral torsional buckling Column buckling Lateral torsional buckling N N N N e Ed Ed = pl, Rk N y, Rk e y,rk 1 1 N 1- N * Ed Ed = pl,rk * = ln - = ln - 0,2 N Ed crit y,rk pl,rk 1 1,2 1- N N 0 = 2 NlN 1 = j 1 j 2 - l N Fl N e Fl Fl Ed y, Ed = Fl pl, Rk y, Rk z, Ed z, Rk j = 0, 5 1 l - 0, 2 l * z, Ed z, crit 1 N Fl crit Fl y, Rk = l - 0,2 N = * e * Fl y,rk Fl pl,rk 1 1- z, Ed z, crit = 1 2 l 1 0,2 2 l - = 2 l Fl 1- l

36 Comparison of LTB-curves LT 1,0 Lateral torsional buckling for GI T =oo Lateral torsional buckling for a beam HEB 200 Bc a Bc b 0,0 0,0 1,0 l2,0 LT 36

Preliminary steel concrete composite bridge design charts for Eurocodes

Preliminary steel concrete composite bridge 90 Rachel Jones Senior Engineer Highways & Transportation Atkins David A Smith Regional Head of Bridge Engineering Highways & Transportation Atkins Abstract