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Challenge the future
DelftUniversity ofTechnology
Development of Stop Criteria for Proof Loading
Eva Lantsoght, Yuguang Yang, Rik Tersteeg, Cor van der Veen, Ane de Boer
2Development of Stop Criteria for Proof Loading
Overview• Introduction• Why proof loading?• Stop criteria?
• Overview of existing guidelines• Lab testing for analysis• Recommendations• Summary and conclusions
Slab shear experiments, TU Delft
3Development of Stop Criteria for Proof Loading
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
4Development of Stop Criteria for Proof Loading
Why load testing? (2)
5Development of Stop Criteria for Proof Loading
Stop criteria
• Safety philosophy• Stop criteria:• Further loading not permitted• Failure near• Irreversible damage near
MSc Thesis W. Vos
6Development of Stop Criteria for Proof Loading
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
7Development of Stop Criteria for Proof Loading
Existing Guidelines for proof loading
• Europe: DAfStB Richtlinie• Stop criteria• Concrete strain• Steel strain• Crack width and residual
crack width• Residual deflection
• For flexure• Structures with large
existing cracking?
8Development of Stop Criteria for Proof Loading
Existing Guidelines for proof loading
• North America: • Buildings: ACI 437.2M-
13• Bridges: Manual of
Bridge Rating Through Load Testing (1998)
• ACI 437.2M-13 stop criteria:• Residual deflection• Permanency ratio• Deviation from Linearity
Index
9Development of Stop Criteria for Proof Loading
Research need
• Guideline for proof loading of existing bridges for the Netherlands
• Flexure + shear• Stop criteria?
10Development of Stop Criteria for Proof Loading
Lab testing for analysis (1)
• Beams from Ruytenschildt Bridge• Cyclic loading protocol• Tests: Failure in shear and flexure• Measurements:
• Lasers: deflection of beam• LVDTs: crack opening • Acoustic emission sensors
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)
11Development of Stop Criteria for Proof Loading
Lab testing for analysis (2)RSB 01F 02A 02B 03F 03Ad (mm) 503 515.5 520 521 515Ac (m2) 0.290 0.297 0.307 0.596 0.537Rebar 4Ø22
4Ø194Ø224Ø19
4Ø225Ø19
9Ø228Ø19
7Ø228Ø19
ρl 0.91% 0.89% 0.96% 0.95% 0.92%
12Development of Stop Criteria for Proof Loading
Lab Testing for analysis (2)• Analysis of stop criteria ACI 437.2M-13 and DAfStB
Richtlinie for RSB03F – Flexure testACI 437.2M-13 Criterion
Load (kN) DAfStBCriterion
Load (kN)
Δr 340 Δr 150Ipr >Pu w new crack 300
IDL 250 Strain -PACI,st 250 PDA,st 150
Pu 606.6 Pu 606.6PACI,st/Pu 0.41 PDA,st/Pu 0.25
Tersteeg, R. H. D. (2015). "Proefbelastingen op betonnen bruggen," B.Sc. Thesis, Delft University of Technology, Delft, The Netherlands, pp. 69.
13Development of Stop Criteria for Proof Loading
Lab Testing for analysis (3)• Analysis of stop criteria ACI 437.2M-13 and DAfStB
Richtlinie for RSB03A – Shear testACI 437.2M-13 Criterion
Load (kN) DAfStBCriterion
Load (kN)
Δr >Pu Δr >Pu
Ipr >Pu w new crack 690
IDL 390 Strain -PACI,st 390 PDA,st 690
Pu 706.7 Pu 706.7PACI,st/Pu 0.55 PDA,st/Pu 0.98
Tersteeg, R. H. D. (2015). "Proefbelastingen op betonnen bruggen," B.Sc. Thesis, Delft University of Technology, Delft, The Netherlands, pp. 69.
14Development of Stop Criteria for Proof Loading
Recommendations• Use cyclic load protocol• Study linearity and repeatability of results
• Flexure: Stop criteria exceeded long before failure• Suitable stop criteria
• Crack width criterion from DAfStB + add lower bound• Residual deflection DAfStB / ACI 437.2M-13 + minimum load level• Deviation from Linearity ACI 437.2M-13: consistent performance
except for retested beam• BUT: Deviation from Linearity and Permanency Ratio depend on
applied loading protocol• Shear: • Need to develop stop criteria• Research on acoustic emission measurements
15Development of Stop Criteria for Proof Loading
Summary and conclusions• Proof loading to approve existing
bridges• Existing guidelines: • Only flexure• Cracked structures?
• Development of stop criteria for Dutch Guideline• Laboratory experiments• Check existing stop criteria
• Stop criteria• Available for flexure• Adaptations for bridges needed• Current research: shear
Viaduct Zijlweg, tested in summer 2015
16Development of Stop Criteria for Proof Loading
Contact:Eva [email protected] // [email protected]+31(0)152787449