Development of Stop Criteria for Proof Loading

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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 LantsoghtE.O.L.Lantsoght@tudelft.nl // elantsoght@usfq.edu.ec+31(0)152787449