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Load testing of structures

Assistant Professor at Universidad San Francisco de Quito en Universidad San Francisco de Quito
5 de Oct de 2018
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Load testing of structures

  1.   Dr. ir. Eva Lantsoght 9/27/2018 1
  2.  Introduction to event  Current activities related to load testing  Overview of load testing research TU Delft  Recommendations o Preparation of proof load tests o Execution of proof load tests  Summary and conclusions Slab shear experiments, TU Delft 9/27/2018 2
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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 9/27/2018 5
  6.  General introduction on load testing  Presentation from Chancellor Grant 2016 o Kevin Benitez: Development of a stop criterion for load tests based on the critical shear displacement theory  Presentations describing current practice in Ecuador o Santiago Camino: Proof loading of the new administration building of Yachay University o Andres Robalino: Bridge diagnostic load testing in Ecuador – case studies 9/27/2018 6
  7.  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 existing structures (corresponding author) + towards new Model Code  Conferences with MS and SS: ACI 2017, IABMAS 2018; IALCCE 2016 + 2018, BEI 2019, fib 2017… 9/27/2018 7
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  9.  ACI SP-323 (co-editor)  Frontiers Built Environment – Bridge Engineering article collection (guest associate editor)  Book: Load Testing of Bridges (editor) – Structures and Infrastructures series (2019) 9/27/2018 9
  10.  At opening of new bridge  Reassure traveling public  Engineer stands under bridge  Proof load testing 9/27/2018 10
  11.  Since 1950s: better computational methods  Diagnostic load testing: SLS  Now: evaluation of existing structures 9/27/2018 11
  12.  Proof load testing of existing bridges  Mostly RC slab bridges  Shear-critical  Safety philosophy  Safe execution?  Theoretical work  Pilot proof load tests  Collapse tests 9/27/2018 12
  13. 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 9/27/2018 13
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  15. Diagnostic load testing Proof load testing 9/27/2018 15 Barcza ridge, Poland (Olaszek et al., 2012) Delaware (Jones, 2011)
  16. 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 9/27/2018 16
  17.  Safety philosophy  Stop criteria: o Further loading not permitted o Failure near o Irreversible damage near MSc Thesis W. Vos 9/27/2018 17
  18.  Apply predetermined load to bridge o Information lacking o Damage due to ASR, …  Proof load testing o Immediate approval of bridge o Recalculate updated β o RC slab bridges 9/27/2018 18
  19.  DAfStB Richtlinie  Stop criteria 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? 9/27/2018 19
  20.  North America: o Buildings: ACI 437.2M-13 o Bridges: Manual of Bridge Rating Through Load Testing (1998)  ACI 437.2M-13 stop criteria: o Residual deflection o Permanency ratio o Deviation from Linearity Index 9/27/2018 20
  21.  Practical recommendations for proof load testing  Flexure + shear  Stop criteria? 9/27/2018 21
  22.  Proof load 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 9/27/2018 22
  23.  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 9/27/2018 23
  24.  Critical position o Bending moment: largest moment o Shear: 2.5d from Support  Required proof load o Same shear or bending moment as with load combination o Value → considered safety level 9/27/2018 24
  25.  Cyclic loading scheme o Acoustic emission measurements o Check linearity and reproducibility of measurements o Check residual deformations  Stop criteria o Evaluated during tests o Research in progress o Criteria for shear failure need to be developed 9/27/2018 25
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  27.  Beams from Ruytenschildt Bridge o Cyclic loading protocol o Tests: Failure in shear and flexure  Beams cast in lab o plain reinforcement o cyclic loading o shear and flexural failure Beams RSB01 after failure (Yang, 2015) Yang, Y. (2015). "Experimental Studies on the Structural Behaviours of Beams from Ruytenschildt Bridge," Stevin Report 25.5-15-09, Delft University of Technology, Delft, 76 pp. Beams RSB02B after failure (Yang, 2015) 9/27/2018 27
  28.  Load testing: international interest  History: prior to opening  Now: existing bridges  Best practices o Identify goals o Preparation o Inspection o Monitoring o Cyclic loading Viaduct Zijlweg, tested in summer 2015 9/27/2018 28
  29.  (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, 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 9/27/2018 29
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  31. Contact: Eva Lantsoght elantsoght@usfq.edu.ec // E.O.L.Lantsoght@tudelft.nl 9/27/2018 31
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