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

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

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

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

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

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

PREPARATION OF LOAD TEST – TARGET PROOF LOAD

Reliability level β Pb

[kN]

Ps

[kN]EC ULS 4.3 1656 1525RBK Design 4.3 1649 1516RBK Reconstruction 3.6 1427 1311RBK Usage 3.3 1373 1262RBK Disapproval 3.1 1369 1257EC 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

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

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)

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

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%

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

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

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

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

Contact:

Eva Lantsoght

E.O.L.Lantsoght@tudelft.nl // elantsoght@usfq.edu.ec

+31(0)152787449