Proof load testing can be a suitable method to show that a bridge can carry the required loads from the code without distress. This paper addresses the preparation, execution, and analysis of a proof load test on a four-span reinforced concrete solid slab bridge, viaduct de Beek. The bridge has one lane in each direction, but was restricted to a single lane, since an assessment showed that the capacity is not sufficient to allow both lanes. For this proof load test, the bridge was heavily equipped with sensors, so that early signs of distress can be seen. The difficulty in this test was that, for safety reasons, only the first span could be tested, but that the lowest ratings were found in the second span. A direct approval of the viaduct by proof loading was thus not possible, and an analysis was necessary after the field test. The result of this analysis is that only by allowing 6.7% of plastic redistribution in the second span, sufficient capacity can be demonstrated.

1. IABSE SYMPOSIUM ENGINEERING THE FUTURE SEPTEMBER 21-23, 2017
PROOF LOAD TESTING
OF VIADUCT DE BEEK
Eva Lantsoght, Rutger Koekkoek, Yuguang Yang,
Cor van der Veen, Dick Hordijk, Ane de Boer

2. OVERVIEW
• Introduction: load testing
• Viaduct De Beek: description
• Preparation of proof load test
• Execution of proof load test
• Assessment of viaduct De
Beek Testing of Ruytenschildt Bridge

3. IABSE SYMPOSIUM ENGINEERING THE FUTURE SEPTEMBER 21-23, 2017
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. PROOF LOAD TESTING OF
BRIDGES
• Apply predetermined load
to bridge
• Information lacking
• Damage due to ASR, …
• Proof load testing
• Immediate approval of
bridge
• Recalculate updated β

5. VIADUCT DE BEEK (1)
• RC slab bridge of 4 spans
• Built in 1963
• Parabolic change in height
• Proof load test at shear- and
flexure-critical position in first
span

6. VIADUCT DE BEEK (2)
• Core drilling: fck = 44.5 MPa &
fcd = 30 MPa
• QR 24 steel (plain bars), fyk =
252 MPa
• Insufficient flexural capacity
• Reduction of 2 lanes to 1 lane
• Lowest capacity: span 2
• But: span 2 over highway =>
testing not allowed for safety

7. PREPARATION OF LOAD
TEST – TARGET PROOF LOAD
Reliability level β Pb
[kN]
Ps
[kN]
EC ULS 4.3 1656 1525
RBK Design 4.3 1649 1516
RBK Reconstruction 3.6 1427 1311
RBK Usage 3.3 1373 1262
RBK Disapproval 3.1 1369 1257
EC SLS 1.5 1070 976
• Find target proof load that results in same sectional moment or
shear as load combination of code
• With LFEA
• Load combination with load factors depending on safety level
• Exception γDL = 1.10

8. PREPARATION OF LOAD
TEST – SENSOR PLAN
• Deflections in longitudinal and
transverse direction
• Vertical deflections at support
• Strain on bottom of concrete
• Opening of existing cracks
• Cracking activity with acoustic
emission sensors
• Load cells for applied loads

9. EXECUTION OF PROOF LOAD
TEST – LOADING PROTOCOL
• Test for bending moment and test for
shear
• Cyclic loading protocol
• Four load levels:
• Low load to check response of all
sensors
• Serviceability Limit State
• RBK Usage Level: maximum required
for assessment
• Eurocode Ultimate Limit State + 6%
(bending test) / + 2% (shear test)

10. EXECUTION OF PROOF LOAD
TEST – LOAD APPLICATION
• Load application:
counterweights on steel
spreader beam; load
transferred to bridge via jacks
• Controlled method for cyclic
loading
• Avoid collapse when large
deformations occur

11. EXECUTION OF PROOF LOAD
TEST – VERIFICATION OF
MEASUREMENTS
• Load-displacement diagram: check
for nonlinear behavior
• Maximum stiffness reduction:
• Bending moment test 16%
• Shear test 10%
• Residual deflection / maximum
deflection
• Bending moment test: 15%
• Shear test: 8%
• Limit ACI: 25%
• Limit DAfStB: 10%

12. ASSESSMENT OF VIADUCT
DE BEEK – SPAN 1
• Proof load test shows immediately that span fulfils
requirements of code
• No signs of distress observed from measurements
• Conclusion: UC ≤ 1.0

13. ASSESSMENT OF VIADUCT
DE BEEK – SPAN 2
• How to extrapolate results from
Span 1 to Span 2?
• Assessment with plastic
redistribution
• Plastic hinge develops in span 2
• Use 6.7% of plastic redistribution
• UC in span = 1.0
• UC over support 0.94

14. ASSESSMENT OF VIADUCT
DE BEEK -
RECOMMENDATIONS
• Verify reinforcement in
Span 2 with scanner
and/or by removing cover
• Check for signs of
corrosion
• Reopen for two lanes of
traffic

15. IABSE SYMPOSIUM ENGINEERING THE FUTURE SEPTEMBER 21-23, 2017
SUMMARY
• Proof load testing to approve existing bridges
• Case study: Viaduct De Beek
• Preparation of load test:
• Target proof load
• Sensor plan
• Execution of load test
• Cyclic loading protocol
• Jacks and steel spreader beam
• Real-time evaluation of measurements
• Analysis of load test
• Assessment of viaduct
• Reporting all results

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