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Proof load testing of viaduct De Beek

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Presentation at IABSE Belgium & the Netherlands

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Proof load testing of viaduct De Beek

  1. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 12. • Video
  13. 13. 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
  14. 14. 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
  15. 15. 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
  16. 16. 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
  17. 17. Contact: Eva Lantsoght E.O.L.Lantsoght@tudelft.nl // elantsoght@usfq.edu.ec +31(0)152787449

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