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5th International Symposium on Weigh-In-MotionHVParis 2008, May 19-22 2008

INTERACTION EFFECT OF TRAFFIC LOADS AND BRIDGE

DETAILS SUSCEPTIBLE TO FATIGUE

Centre of Public Works, The Netherlands

[email protected], [email protected]

5th International Conference on Weigh-In-MotionHVParis 2008, May 19-22 2008

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Fatigue interaction effectsContentsContents

1.1. IntroductionIntroduction2.2. PrinciplesPrinciples

•• Fatigue resistance Fatigue resistance •• Load effects Load effects •• Fatigue life calculationsFatigue life calculations

3. 3. Traffic loadsTraffic loads•• Axle loads Axle loads •• Lorry loadsLorry loads

4. 4. ExampleExample5. 5. ConclusionConclusion


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2.1 2.1 FatigueFatigue resistanceresistance

0,1

1

10

1,00

E+04

1,00

E+05

1,00

E+06

1,00

E+07

1,00

E+08

1,00

E+09

N (cycles to failure)

Stre

ss q

uotie

ntS-N line (steel)

Constant amplitudelimitCut-off limit

FatigueClassification

i

ii N

nD = ).......( 321 nDDDDD +++Σ=


4

2.2 2.2 LoadLoad effectseffects


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2.3 2.3 FatigueFatigue lifelife calculationscalculations

Equivalent Equivalent nrnr of of cyclescycles forfor 150 150 kNkN axlesaxles

⎪⎭

⎪⎬⎫

⎪⎩

⎪⎨⎧

+⎟⎟⎠

⎞⎜⎜⎝

⎛∆∆

+⎟⎟⎠

⎞⎜⎜⎝

⎛∆∆

+⎟⎟⎠

⎞⎜⎜⎝

⎛∆∆

+⎟⎟⎠

⎞⎜⎜⎝

⎛∆∆

⋅⎟⎟⎠

⎞⎜⎜⎝

⎛

∆∆

+

+⎟⎟⎠

⎞⎜⎜⎝

⎛

∆∆

+⎟⎟⎠

⎞⎜⎜⎝

⎛

∆∆

+⎟⎟⎠

⎞⎜⎜⎝

⎛

∆∆

+⎟⎟⎠

⎞⎜⎜⎝

⎛

∆∆

=

.....

........

5

1414

5

1313

5

1212

5

1111

3

150,

3

150,

44

3

150,

33

3

150,

22

3

150,

11150,,

etcnnnn

nnnnn

DDDDa

D

aaaaaeq

σσ

σσ

σσ

σσ

σσ

σσ

σσ

σσ

σσ

Equivalent nr. Equivalent nr. nneqeq of of cyclescycles forfor ∆∆σC, Cumulative damage of axlesDa, Number of axles to failure Na

6,

102xn

D Ceqa =

Ceqa n

xN,

6102=

3150,

150,,, ⎟⎟⎠

⎞⎜⎜⎝

⎛∆∆

=C

aaeqCeq nn

σσ


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3 3 TrafficTraffic loadsloads

Exceedance probability axle loads

Measurements at Moerdijk Bridge 1998, 2004 and filtered measurements 2004


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3 3 TrafficTraffic loadsloads ctdctd..

Exceedance probability Lorry loads

Measurements at Moerdijk Bridge 1998, 2004 and filtered measurements 2004


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3.1 3.1 AxleAxle loadsloadsEN 1991-2 FLM4 Moerdijk 1998 1.25 x Moerdijk 1998 Axle load (kN) P/150 Fraction P/150 Fraction P/150 Fraction

210 1.400 0 1.75 0 200 190 1.267 0.0001 1.584 0.0001 180 170 1.133 0.0002 1.416 0.0002 160 150 1 0.121 1 0.0002 1.25 0.0002 140 0.933 0.036 130 0.867 0.072 0.867 0.016 1.083 0.016 120 0.800 0.024 110 0.067 0.067 0.917 0.067 90 0.600 0.458 0.600 0.136 0.750 0.136 80 0.533 0.048 70 0.467 0.241 0.467 0.339 0.583 0.339 50 0.333 0.379 0.417 0.379 30 0.200 0.272 0.250 0.272 10 0.067 0.059 0.083 0.059 Weighted average

97 kN 73 kN 91 kN


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Fatigue life (nr. of axles)Fatigue life (nr. of axles)


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RelationRelation betweenbetween fatiguefatigue lifelife forfor Moerdijk 1998 Moerdijk 1998 and 1.25 Moerdijk 1998 (and 1.25 Moerdijk 1998 (axlesaxles))


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LorryLorry loadsloads and and distributionsdistributions

FLM4 Moerdijk Silhouette Fraction Equivalent

load (kN) P/490 Fraction Maximum

load (kN) Effective load (kN)

P/490

↓--↓ 0.20 200 0.41 0.17 190 145 0.30 ↓--↓↓ 0.05 310 0.63 0.03 265 202 0.41 ↓↓--↓↓ 0.06 370 282 0.58 ↓--↓-↓--↓ 0.15 390 0.80 0.08 390 297 0.61 ↓--↓↓-↓--↓ 0.05 465 354 0.72 ↓--↓-↓--↓↓ 0.10 450 0.92 0.03 470 356 0.73 ↓--↓↓-↓--↓↓ 0.03 535 408 0.83 ↓--↓--↓ 0.03 290 221 0.45 ↓--↓--↓↓ 0.12 370 282 0.58 ↓--↓--↓↓↓ 0.50 490 1 0.35 460 350 0.71 ↓--↓↓--↓ 0 365 277 0.57 ↓--↓↓--↓↓ 0.01 445 339 0.69 ↓--↓↓--↓↓↓ 0.04 535 408 0.83 Weighted average 447 kN 386 kN 294 kN


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Numbers of lorries until failureNumbers of lorries until failure


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RelationRelation betweenbetween fatiguefatigue lifelife of Moerdijk 1998 of Moerdijk 1998 and 1.25 Moerdijk 1998 (lorries)and 1.25 Moerdijk 1998 (lorries)


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3.3 3.3 ConclusionsConclusions traffictraffic loadload increaseincrease

•• LocationsLocations withwith lowlow stressesstresses show a long show a long fatiguefatigue lifelife butbut are are relativelyrelatively highlyhighly susceptiblesusceptible toto increaseincrease of of traffictraffic loadsloads

•• 1.25 x 1.25 x axleaxle//lorrylorry loadload fatiguefatigue lifelife reductionreduction toto 0.020.02

•• LocationsLocations withwith higherhigher stressesstresses show a short show a short fatiguefatigue lifelife butbutare are relativelyrelatively lessless susceptiblesusceptible toto increaseincrease of of traffictraffic loadsloads

•• 1.25 x 1.25 x axleaxle loadload fatiguefatigue lifelife reductionreduction toto 0.50.5

•• 1.25 x 1.25 x lorrylorry loadload fatiguefatigue lifelife reductionreduction toto 0.80.8


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4 Example4 Example Stress interval bottom flange = 60N/mm2

Detail class parent material 140 N/mm2

SQ = 0.3 (max veh. Load SQ 0.8): No fatigue

1.25 x SQ = 0.54: 8.7 x 108 Lorries

Detail class attachment 75 N/mm2

SQ = 0.6:

1.25 x 108 Lorries

or 100 years Moerdijk 1998 traffic

1.25 x SQ = 0.75:

3.6 x 107 Lorries

or 29 years Moerdijk 1998 x 1.25 traffic


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Fatigue interaction effects5 5 ConclusionConclusion

A moderate A moderate increaseincrease of of loadsloads cancan causecause a a severeseverereductionreduction of the of the fatiguefatigue lifelife

6 6 ReferencesReferences•• EN 1991EN 1991--2, EC 1: 2, EC 1: ActionsActions onon structuresstructures –– Part 2 Part 2 TrafficTraffic loadsloads onon

bridgesbridges•• EN 1991EN 1991--11--9, EC 3: Design of steel 9, EC 3: Design of steel structuresstructures ––Part 1.9 Part 1.9 FatigueFatigue•• MoTMoT NL, NL, FinalFinal report report axleaxle loadload measurementsmeasurements Moerdijk 1998, IBMoerdijk 1998, IB--

RR--9898--47 47 •• TNO report TNO report GeneralGeneral probabilisticprobabilistic considerationsconsiderations forfor reliabilityreliability and and

modellingmodelling of of traffictraffic loadsloads forfor roadroad bridgesbridges, 98, 98--CONCON--R1813R1813

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