Flutter analysis of an Flutter analysis of an extradosed bridge in Hungary extradosed bridge in Hungary M M á á ty ty á á s HUNYADI s HUNYADI Budapest University of Technology and Economics Budapest University of Technology and Economics (BME) (BME) Department of Structural Engineering Department of Structural Engineering hunyadi@ hunyadi@ vbt.bme.hu vbt.bme.hu
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Flutter analysis of an extradosed bridge in Hungary · Flutter analysis of an extradosed bridge in Hungary Máty ás HUNYADI Budapest University of Technology and Economics (BME)
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Flutter analysis of an Flutter analysis of an extradosed bridge in Hungaryextradosed bridge in Hungary
MMáátytyáás HUNYADIs HUNYADI
Budapest University of Technology and EconomicsBudapest University of Technology and Economics (BME)(BME)Department of Structural EngineeringDepartment of Structural Engineering
Courtesy of PontCourtesy of Pont--TERVTERVFlutter instability investigation:Flutter instability investigation:�� construction phase (cantilever stage)construction phase (cantilever stage)�� final phasefinal phase
Force Force coeffscoeffs. . -- derivativesderivatives
a=0a=0°°Limit state values
-5,00
-4,00
-3,00
-2,00
-1,00
0,00
1,00
2,00
0,00 0,20 0,40 0,60 0,80 1,00 1,20 K×H1*
K^2×A3*
dCL/da
dCM/da
αd
dcKH LK
→→ 0*
1
αd
dcAK MK
→→ 0*
3
2
K
Flutter conditionFlutter condition
Affinity in the crossAffinity in the cross--terms:terms:
43514,30 T4,85-6
22615,30 B2,450
3,84*15,28 *0,040,90
2,472,33
+6
56,1214,40 T0,62-6
47,93,46 B2,200
12,87*3,47 *0,59
1,002,800,55
+6
U0crit
[m/s]
ωcrit
[1/s]
U red,crit
[-]
ΦfT
[1/s]
fB
[1/s]
α
[°]
*
3
*
2
*
4
*
1,,, HHAA ΦΦΦΦ
Damping factor: 3,5%Damping factor: 3,5%
Max. wind speedMax. wind speed
�� Lack of wind map for Hungary Lack of wind map for Hungary �� middlemiddle--GermanyGermany
�� 10 min average wind velocity10 min average wind velocity
�� 2020--30 oscillations for instability 30 oscillations for instability �� duration of 5 sec duration of 5 sec
�� p=0,02 annual probability of exceedencep=0,02 annual probability of exceedence
�� maximum wind speed 35,5 maximum wind speed 35,5 m/sm/s
�� safety against flutter instability safety against flutter instability ((UUccritrit //UUmaxmax))22 = (47= (47,,9/359/35,,5)5)22 = = 11,,8282
ConclusionConclusion
�� Enough safety against flutter instabilityEnough safety against flutter instability
�� More measures in the highly nonMore measures in the highly non--stationary domain,stationary domain,at low reduced velocitiesat low reduced velocities
�� Acceptable setAcceptable set--up, but a special test rig could be up, but a special test rig could be designeddesigned
�� More verification during the wind tunnel testMore verification during the wind tunnel test
Thank you for your kind attentionThank you for your kind attention
AcknowledgementsAcknowledgements�� dr. I. dr. I. HegedHegedűűss, BME, BME�� dr. I. dr. I. KovKováácscs, Dynamic, Dynamic--Consulting (BRD)Consulting (BRD)for their comments and help in this workfor their comments and help in this work