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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: 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 // 5/22/2020 30