Load testing of structures
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Dr. Eva Lantsoght provides an overview of her current activities related to load testing research at TU Delft. She discusses (1) her involvement in developing new load testing standards in several countries, (2) conferences where she has presented on the topic, (3) load testing projects she has conducted including beam experiments and full-scale bridge tests, and (4) recommendations for preparing and executing proof load tests on existing bridges.
Load testing of structures
- 1. Dr. ir. Eva Lantsoght 5/22/2020 1
- 2. Current activities relatedto load testing Overviewof load testing researchTU Delft Recommendations o Preparation of proof load tests o Execution of proof load tests Summary and conclusions Slab shear experiments, TU Delft 5/22/2020 2
- 3. New load testing standards under development o Germany o USA – e-circular load testing bridges (committee chair) o USA – ACI 437 for buildings (committee member) o USA – ACI 342 for bridges (broader scope, chapter lead for chapter load testing) o Netherlands: further research o fib – bulletin existingstructures (corresponding author) + towards new Model Code Conferences with MS and SS: ACI 2017, IABMAS 2018; IALCCE 2016 + 2018, BEI 2019, fib 2017… 5/22/2020 3
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- 5. Presentations from Chancellor Grant 2016 at IALCCE 2018 o Kevin Benitez: Development of a stop criterion for load tests based on the critical shear displacement theory o Eva Lantsoght: Proposed stop criteria for proof load testing of concrete bridges and verification o Jose Eduardo Paredes: Nonlinear finite element analysis of beam experiments for stop criteria o Andres Rodriguez: Verification of flexural stop criteria for proof load tests on concrete bridges based on beam experiments Presentation describing current practice in Ecuador at IALCCE 2018 o Bridge diagnostic load testing in Ecuador – case studies J. Bonifaz, S. Zaruma, A. Robalino & T.A. Sánchez 5/22/2020 5
- 6. September 15th 2020: Deadline for abstract submission Towards extending the service life of existing concrete infrastructure through advanced assessment methods (Special session) 5/22/2020 6
- 7. ACI SP-323 (co-editor) Frontiers Built Environment– Bridge Engineering article collection(guest associate editor) Two Books: Load Testingof Bridges (editor) – Structures and Infrastructuresseries (2019) 5/22/2020 7
- 8. E-circular 5/22/2020 8 Download link: http://onlinepubs.trb.org/onlinepubs/circulars/ec257.pdf Primary Contributors: Sreenivas Alampalli, NYS DOT Dan M. Frangopol, Lehigh University Jesse Grimson, BDI David Kosnik, CTL Group Marvin Halling, Utah State University Eva O.L. Lantsoght, USFQ & Delft Jeff S. Weidner, University of Texas David Y. Yang, Lehigh University Y. Edward Zhou, AECOM Reviewed by: Erin Bell, University of New Hampshire Christina Freeman, FL DOT James Long, PA Brent Phares, Iowa University Franklin Moon, Rutgers University Duane Otter, TTCI Thomas E. Beitelman, AASHTO T-18 /FL DOT Stephen Maher, TRB
- 9. At opening of new bridge Reassure traveling public Engineer stands under bridge Proof load testing 5/22/2020 9
- 10. Since 1950s: better computational methods Diagnostic load testing: SLS Now: evaluation of existing structures 5/22/2020 10
- 11. Proofload testingof existing bridges Mostly RC slab bridges Shear-critical Safety philosophy Safe execution? Theoreticalwork Pilot proof load tests Collapse tests 5/22/2020 11
- 12. Bridges from 60s and 70s The Hague in 1959 Increasedlive loads common heavy and long truck (600 kN) End of service life + larger loads 5/22/2020 12
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- 14. Diagnostic load testing Proof load testing 5/22/2020 14 Barcza ridge, Poland (Olaszek et al., 2012) Delaware (Jones, 2011)
- 15. Diagnostic load testing Calibration of FEM Strain gages over girder height Low load levels (SLS) Rating with updated FEM Or: prior to opening (presentation Andres R.) Proof load testing Directly demonstrate that bridge fulfils criteria Higher load levels Larger involved risk Follow measurements Stop criteria 5/22/2020 15
- 16. Safety philosophy Stopcriteria: o Further loading not permitted o Failure near o Irreversible damage near MSc Thesis W. Vos 5/22/2020 16
- 17. Apply predetermined load to bridge o Information lacking o Damage due to ASR, … Proofload testing o Immediate approval of bridge o Recalculate updated β o RC slab bridges 5/22/2020 17
- 18. DAfStB Richtlinie Stopcriteria o Concrete strain o Steel strain o Crack width and residual crack width (new & existing cracks) o Residual deflection For flexure Structures with large existing cracking? 5/22/2020 18
- 19. North America: o Buildings: ACI 437.2M-13 o Bridges: Manual of Bridge Rating Through Load Testing (1998) ACI 437.2M-13 stopcriteria: o Residual deflection o Permanency ratio o Deviation from Linearity Index 5/22/2020 19
- 20. Practical recommendations for proof load testing Flexure + shear Stop criteria? 5/22/2020 20
- 21. Proofload tests: o Heidijk 2007 o Medemblik 2009 o Vlijmen-Oost 2013 o Halvemaans Bridge 2014 o Ruytenschildt Bridge 2014 o Viaduct in the Zijlweg 2015 o Viaduct De Beek 2015 o Vecht Bridge 2016 Load test to failure of Ruytenschildt Bridge, summer 2014 5/22/2020 21
- 22. Field inspection o Dimensions o Same lay-out as plans? o Material properties o Damage maps o Site restrictions Prior assessment o Live load: EN 1991-2:2003 o RBK load levels 5/22/2020 22
- 23. Critical position o Bending moment: largest moment o Shear: 2.5d from support Requiredproof load o Same shear or bending moment as with load combination o Value → considered safety level 5/22/2020 23
- 24. Cyclic loading scheme o Acoustic emission measurements o Check linearity and reproducibility of measurements o Check residual deformations Stopcriteria o Evaluated during tests o Research in progress o Criteria for shear failure need to be developed 5/22/2020 24
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- 26. Beamsfrom Ruytenschildt Bridge o Cyclic loading protocol o Tests: Failure in shear and flexure Beamscast in lab o plain reinforcement o cyclic loading o shear and flexural failure Beams RSB01 after failure (Yang, 2015) Yang, Y. (2015)."Experimental Studieson theStructural Behavioursof Beamsfrom RuytenschildtBridge," Stevin Report 25.5-15-09,Delft Universityof Technology, Delft, 76 pp. Beams RSB02B after failure (Yang, 2015) 5/22/2020 26
- 27. Load testing:internationalinterest History:prior to opening Now: existingbridges Best practices o Identify goals o Preparation o Inspection o Monitoring o Cyclic loading Viaduct Zijlweg, tested in summer 2015 5/22/2020 27
- 28. (Former) colleagues at TU Delft: Albert Bosman, Sebastiaan Ensink, Dick Hordijk, Rutger Koekkoek, Marco Roosen, Cor van der Veen, Patrick van Hemert, Yuguang Yang Students at TU Delft: Arthur Ennoudi, Thomas Harrewijn, Rik Tersteeg, Werner Vos Rijkswaterstaat: Ane de Boer, Sonja Fennis, Marius Naaktgeboren, Herbert van der Ham Contractors: de Boer en de Groot, Witteveen+Bos (Frank Linthorst, Danny den Boef) Load execution: Mammoet: Otto Illing, Chris Huissen Funding: Noord Holland, Friesland, Rijkswaterstaat, Chancellor Grants USFQ 5/22/2020 28
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- 30. Contact: Eva Lantsoght elantsoght@usfq.edu.ec // E.O.L.Lantsoght@tudelft.nl 5/22/2020 30