Presentation given at Jornadas de Ingenieria Civil, Escuela Politecnica Nacional

1. Challenge the future
Delft
University of
Technology
Proof loading of existing bridges
Recent developments in The Netherlands
Dr. ir. Eva Lantsoght, Prof. dr. ir. Dick Hordijk, Dr. ir. Cor van der Veen, Dr. ir. Ane de Boer

2. 2Proof loading of existing bridges
Overview
• Introduction
• Applied methods
• Results
• Summary and conclusions
Slab shear experiments, TU Delft

3. 3Proof loading of existing bridges
Background (1)
Bridges from 60s and 70s
The Hague in 1959
Increased live loads
common heavy and long truck (600 kN)
End of service life + larger loads

4. 4Proof loading of existing bridges
Background (2)

5. 5Proof loading of existing bridges
Background (3)
• Replacing all bridges = too
expensive
=> Prioritize efforts!
Highways in the Netherlands

6. 6Proof loading of existing bridges
Principle of Levels of Approximation
Model Code 2010 (1)
• Approach from fib Model
Code 2010
• Solution strategy = different
levels of approximation
• Eg: Shear capacity in Model
Code 2010

7. 7Proof loading of existing bridges
Principle of Levels of Approximation
Model Code 2010 (2)
• For assessment:
• LoA 1: Quick Scan
• LoA 2: LFEA
• LoA 3: NLFEA +
probabilistic analysis
• LoA 4: Proof loading

8. 8Proof loading of existing bridges
Proof loading of bridges
• Apply predetermined load to
bridge
• Information lacking
• Damage due to ASR, …
• But: probabilistic analysis
• Maximum load?
• “Stop criteria”?

9. 9Proof loading of existing bridges
Current codes for proof loading
• Europe: DAfStB Richtlinie
• North America:
• Buildings: ACI 437.2M-13
• Bridges: Manual of Bridge
Rating Through Load
Testing (1998)
• But: stop criteria for cracked
structures?

10. 10Proof loading of existing bridges
Research need
• Guideline for proof loading of existing bridges for The
Netherlands
• Flexure + shear
• Stop criteria?

11. 11Proof loading of existing bridges
Methods
• Proof load tests:
• Vlijmen-Oost
• Halvemaans Bridge,
Alkmaar
• Ruytenschildt Bridge
• Viaduct in the Zijlweg

12. 12Proof loading of existing bridges
Vlijmen-Oost
• Loading: BELFA
• Viaduct with ASR
• Testing while viaduct was in
service
• Measurements:
• Lasers
• Acoustic emissions
• LVDTs

13. 13Proof loading of existing bridges
Halvemaans Bridge Alkmaar
• Load application: Mammoet
• Flexural capacity
• Bridge closed for 1 night
• Measurements:
• Lasers
• Acoustic emissions
• LVDTs

14. 14Proof loading of existing bridges
Ruytenschildt Bridge (1)
• Load application: Mammoet
• Measurements:
• Lasers
• Acoustic emissions (2 teams)
• LVDTs
• Sawcut for testing
• Testing to failure

15. 15Proof loading of existing bridges
Ruytenschildt Bridge (2)
• Study cracks and deformations for applied loads
• Crack formation: acoustic emissions measurements
• Control load process

16. 16Proof loading of existing bridges
Proofloading Ruytenschildt Bridge
Existing bridge Partial demolition and building new bridge

17. 17Proof loading of existing bridges
Ruytenschildt Bridge (4)

18. 18Proof loading of existing bridges
Viaduct in the Zijlweg
• Loading: Mammoet
• Viaduct with ASR
• Viaduct closed for 1 week
• Measurements:
• Lasers
• Acoustic emissions
• LVDTs

19. 19Proof loading of existing bridges
Results of proof load tests (1)
• Load application method:
• Hydaulic jacks: allows higher
load on wheel prints
• BELFA: limited to 90 ton

20. 20Proof loading of existing bridges
Results of proof load tests (2)
• Determination of maximum
load in test:
• Moment due to applied load
• = moment due to Eurocode
loads
• Find critical location
• Same procedure for shear
• Use LFEA

21. 21Proof loading of existing bridges
Results of proof load tests (3)
• Different reliability levels
• As prescribed by NEN 8700:2011
• Different requirements for structure
• Different partial load factors
Case Ptot (kN) Ptot
(metric ton)
EC 1259 128
RBK Design 1257 128
RBK Reconstuction + 5% 1146 117
RBK Reconstruction 1091 111
RBK Usage 1050 107
RBK Disapproval 1049 107
SLS 815 83

22. 22Proof loading of existing bridges
Results of proof load tests (4)
0
20
40
60
80
100
120
0 50 100 150
Appliedtotalload
[tonnes]
Time [min]
Loading procedure SLS Reconstruction Reconstruction + 5%

23. 23Proof loading of existing bridges
Results of proof load tests (5)
• Measurements: experience
• Development of aluminum
frame
• Research on Acoustic
Emissions
• Necessary for stop criteria
• Load cells at jacks
LVDT
Laser distance
finder

24. 24Proof loading of existing bridges
Summary and conclusions
• Proof loading: LoA 4
• Research in The Netherlands
• Executed load tests
• Loading with hydraulic jacks
• Measurement and
interpretation
• Current work:
• Determination of maximum
load
• Stop criteria

25. 25Proof loading of existing bridges
Contact:
Eva Lantsoght
E.O.L.Lantsoght@tudelft.nl // elantsoght@usfq.edu.ec
+31(0)152787449