presentatie bridge hagestein
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8/9/2019 Presentatie Bridge Hagestein
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22/03/2012 1
Bridge Hagestein
Modified sliding elements and guides in
new bearings
J.S.Leendertz, Ministry of Transport NL
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• 3 Span plate girder twin bridge on Motorway A27• Built 1980
• Each bridge: 2 main girders, H = 3.5, at piers 5.8 m,crossbeams c.o.c. 4.0 m, orthotropic steel deck• Each bridge is supported by 8 spherical bearings
• 100.000 vehicles/day, incl. 14.000 lorries(Northbound + Southbound)
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Support system after renovation
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Dimpled PTFE-disc with remains of lubricant
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Discussion on damages:
1. Black grease
2. Dimples
3. Lipping (circular, or one sided)
What is the mechanism behind it?
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Worn out Guide
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Discussion on state of guides:
1. Where is the DU-B (or CM) material
2. Worn out steel surfaces
What might be the mechanisms?
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Vertical deflections and rotations undertraffic loads
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Longitudinal shift and rotations of bearingsfor midspan load
Rotation of bridge cross section aboutshear centre
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Combination of rotation and transverse effects (effectof bearing centre to neutral axis distance excluded)
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The sliding elements must fulfil the followingrequirements:
1. Contact stresses not too high to limit extrusion of
PTFE (lipping)2. Contact stresses not too low to maintain the sealingeffect
3. No partial separation to avoid redistribution oflubricant and danger of dislocation of PTFE
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t 0m
t t 20m 10.000m
t 10.020m
t t 10.040m
d EN1337
MPA T1 -35 T 2 +35 T 3 +21 +21 T +30 T 1 -35 T 2 +35 T 3 +21 press ure=30 0.023
(0.008)0.006(0.003)
0.008-
press ure=50-
0.054(0.022)
0.025(0.008)
0.027- (0.030)
GLACIER - - T room T room - - - press ure=30 - -
0.011 Start0.009 End
press ure=280.011 Start0.010 End0.023 After dwell
- - -
0,00
0,02
0,04
0,06
0,08
0,10
coefficient of frictionµm
ax
-40
-20
0
20
40
60
temperature T
100 200 300 400 900 1000 1100 number of strokes n1
0 2 4 6 8 16 18 20 22 total slide path s t
PTFE white
m
µ
T
T (comparison test))
°C
Coefficient of friction for model bearings with a dimple greased (silicon grease) PTFE+UHMWPE ring systemor PTFE as sliding element and austenitic steel as mating surface at the end of a long term test with a total slide
path of about 10000 m
p= 30 MPa, s = 0...10 mm, v = 0,4 mm/s, t v,u = 1 h(with PTFE+UHMWPE ring p = 50 MPa for most of the long term test)
VirginPTFE
PTFE +UHMWPERing
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Testing location Specimen type Wear products(g)
Decrease of protrusion(mm)
Observations
MPA p=50
PTFE +UHMWPE-ring
2.2
19.5
5000m: 0.6810.000m: 0.625000m: 0.68
10.000m: 2.20
Severe lipping of ring insliding direction, 4.3 - 5.4mmPartial collapse of ring in
direction perpendicular tothe sliding direction, 4.8 -5.0mm
MPA p=50
PTFE - - Worn out after 2500m
Glacier p=30
PTFE +UHMWPE-ring
0.1250.084
- Minor lipping, 0.9mmMinor lipping, 0.8mm
Wear:
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Test specimen for guides
Testinglocation
t 0m
t t
20m 10.000mt
10.020mt t
10.040md
EN 1337MPA T 1 -37 T 2 +35 T 3 +21 Controlled Temp. at
MPA
T1 -37 T 2 +35 T 3 +21
UHMWPE pres sure=30
0.040 0.010 0.012 pressure=50 0.098 0.042 0.047 -
PTFE pres sure=30
0.110 - 0.040 pressure=30 0.107(5000m)
- 0.060 0.060
CM1 pres sure=75
0.137 - 0.047 pressure=75 0.151(5.000m)
- 0.065 0.080
Testing locationMPA
Specimen type Wear production(g)
Decrease of protrusion(mm)
Observations
p=50UHMWPE-strip none
none
5000m: 0.5510.000m: 0.425000m: 0.5310.000m: 0.80
Lipping 1.3 - 1.8mm
Lipping 3.4 - 4.6mm
Friction coefficients
Wear
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0,00
0,02
0,04
0,06
0,08
0,10
0,12
0,14
0,16
coefficientoffrictionµ
max
-80
-60
-40
-20
0
20
40
60
80
temperature T
100 200 300 400 900 1000 1100 number of strokes n1
0 2 4 6 8 16 18 20 22 total slide path s t
DU-B (5 km-comparison test) *PTFE stripes (5 km-comparison test) *
m
µ
T
T (DU-B-comparison test)
DU-B
PTFE
PE
°C
Coefficient of friction for model bearings with initially lubricated strips of UHMWPE, CM 1 (DU-B)and unlubricated PTFE as sliding element and austenitic steel as mating surface for the last 22/20 m ofa long term test. Total slide path of about 10.000 m for UHMWPE and 5000 m for PTFE and CM 1s = 0...10 mm, v = 0.4 mm/s, t v,u = 1 h,
p= 30 N/mm 2 for UHMWPE and PTFE, p= 75 N/mm 2 for CM 1(with UHMWPE p = 50 N/mm 2 for the long term test)
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R 8 0 0
R 8 0 8
1 4 1
1 2 2
3 0 3
1 5 2
750
ø570
ø530
ø490
1080
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Experiences until now and conclusions:
•
The bearings show almost no wear after 7 years ofservice
• The sliding systems provide a with respect to frictioncoefficients reasonable and very durable solution
• The supports for the guides show to be susceptible tofatigue
And:Solving one problem can introduce other problems
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