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- 1. Challenge the future Delft University of Technology Application of Modified Bond Model to capacity of Ruytenschildt Bridge Eva Lantsoght, Cor van der Veen, Ane de Boer, Dick Hordijk
- 2. 2 Overview • Introduction to case • Modified Bond Model • Test results • Comparison results and MBM • Summary & Conclusions Slab shear experiments, TU Delft
- 3. 3 Proofloading Case Ruytenschildt Bridge • Proofloading to assess capacity of existing bridge • ASR affected bridges • Insufficient information • Study cracks and deformations for applied loads • Crack formation: acoustic emissions measurements • Control load process • Ruytenschildt Bridge: testing to failure
- 4. 4 Proofloading Ruytenschildt Bridge Existing bridge Partial demolition and building new bridge
- 5. 5 Proofloading Case Ruytenschildt Bridge
- 6. 6 Bond Model (1) • Alexander and Simmonds, 1990 • For slabs with concentrated load in middle
- 7. 7 Bond Model (2)
- 8. 8 Modified Bond Model (1) • Adapted for slabs with concentrated load close to support • Geometry is governing as in experiments • Determine factor that reduces capacity of “radial” strip • Maximum load: based on sum capacity of 4 strips
- 9. 9 Unequal loading of strips • Static equilibrium • v2,x reaches max before v1,x ' 1, 0.1667x c a v f d L a
- 10. 10 Loads close to free edge Edge effect: when length of strip is too small to develop loaded length lw
- 11. 11 Cross-sections Ruytenschildt Bridge • Testing in span 1 and span 2 • close to end support • close to mid support • Critical position for shear
- 12. 12 Test results proofloading Span 1 • Maximum load 3049 kN • Maximum available load for span 1 • Flexural cracks • No failure • Order additional load for test 2! • Prediction MBM: 2864 kN • Tested/Predicted = 1.06 • Tested; not failure load 0 500 1000 1500 2000 2500 3000 3500 0 5000 10000 15000 20000 25000 Load(kN) time (s)
- 13. 13 Test results proofloading Span 2 • Maximum load 3991 kN • Large flexural cracks • Flexural failure • yielding of reinforcement • Settlement of bridge pier with 1.5cm • Elastic recovery to 8mm • Prediction MBM: 3816 kN • Tested/Predicted = 1.05 • Bent-up bars?? 0 500 1000 1500 2000 2500 3000 3500 4000 4500 0 2000 4000 6000 8000 10000 Load(kN) Time(s)
- 14. 14 Conclusions • Ruytenschildt Bridge • Testing to failure in 2 spans • Measurements • Modified Bond Model • Plasticity-based model • For analysis of capacity of slabs • MBM shows good predictions of capacity of bridge • For limited number of field experiments
- 15. 15 Contact: Eva Lantsoght E.O.L.Lantsoght@tudelft.nl // elantsoght@usfq.edu.ec +31(0)152787449