presentation given at ACI Spring Convention 2017 during 437 meeting

1. Challenge the future
Delft
University of
Technology
Proof load testing in the Netherlands
Eva Lantsoght
Overview of current research

2. 2
Overview
• Introduction
• Why proof loading?
• Existing guidelines?
• Pilot proof load tests
• Laboratory experiments
• Recommendations
• Preparation of proof load tests
• Execution of proof load tests
• Analysis of proof load tests
• Summary and conclusions
Slab shear experiments, TU Delft

3. 3
Why load testing? (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. 4
Safety philosphy of proof load testing
• Safety philosophy
• Stop criteria:
• Further loading not permitted
• Failure near
• Irreversible damage near
MSc Thesis W. Vos

5. 5
Existing Guidelines for proof loading
• Europe: DAfStB Richtlinie
• Originally derived for
buildings
• Plain and reinforced
concrete
• For flexure

6. 6
Existing Guidelines for proof loading
• North America:
• Buildings: ACI 437.2M-13
• Bridges: Manual of Bridge
Rating Through Load
Testing (1998)
• ACI 437.2M-13:
• Proof load testing load
combination
• Acceptance criteria for
flexure
• Cyclic loading protocol

7. 7
Research need
• Guideline for proof loading of existing RC slab bridges for
the Netherlands
• Flexure + shear
• Measurements? Target proof load?

8. 8
TU Delft Proof Load Tests
• Proof load tests:
• Heidijk 2007
• Medemblik 2009
• Vlijmen-Oost 2013
• Halvemaans Bridge 2014
• Ruytenschildt Bridge 2014
• Viaduct Zijlweg 2015
• Viaduct De Beek 2015
Load test to failure of Ruytenschildt Bridge, summer 2014

9. 9
Beam tests
• Ruytenschildt beams
• Cyclic loading protocol
• Analysis of stop criteria
• Beams with plain bars
• Effect of number of cycles
• Effect of loading speed
• Load levels
• Analysis of stop criteria
Beams RSB01 after failure (Yang, 2015)
Yang, Y. (2015). "Experimental Studies on the Structural Behaviours of Beams from Ruytenschildt Bridge,"
Stevin Report 25.5-15-09, Delft University of Technology, Delft, 76 pp.
Beams RSB02B after failure (Yang, 2015)

10. 10
Preparation steps (1)
• Preliminary inspection and
rating
• Determination of dimensions
• Live load: EN 1991-2:2003
• RBK load levels
• Different β
• Different load factors

11. 11
Preparation steps (2)
• Critical position
• Bending moment: largest
moment
• Shear: 2.5d from support
• Required proof load
• Same shear or bending
moment as with load
combination
• Value → considered safety
level

12. 12
Preparation steps (3)
• Sensor plan:
• Deflection profiles in longitudinal
and transverse direction
• Deflection at supports
• Strain on bottom of cross-section
• Reference strain measurements to
correct for T
• Opening existing cracks
• Opening new cracks
• Applied load => load cells
• Acoustic emission measurements
(current research)

13. 13
Execution steps (1)
• Cyclic loading scheme
• Acoustic emission measurements
• Check linearity and reproducibility of measurements
• Check residual deformations => no non-linearity
• Load levels ≈ safety levels CC3 RBK:
• Low level to check instrumentation
• SLS
• Intermediate level
• Target proof load

14. 14
Execution steps (2)

15. 15
Analysis Steps (1)
• Data analysis
• Correct for T
• Correct for support
displacements
• Make final plots for report

16. 16
Discussion and future research
• Minimum measurements
• “Quick and easy” method
for practice
• Improvement of stop criteria
for shear
• Draft guidelines submitted
to RWS in December

17. 17
Summary and conclusions
• Proof loading to approve existing
bridges, also for shear
• Pilot proof load tests in the Netherlands
+ beam tests
• Current recommendations
• First draft guidelines for practice
submitted
Viaduct Zijlweg

18. 18
Contact:
Eva Lantsoght
E.O.L.Lantsoght@tudelft.nl // elantsoght@usfq.edu.ec
+31(0)152787449