1) The document proposes stop criteria for proof load testing of concrete bridges to determine if the structure can withstand increased live loads without irreversible damage. 2) The proposed stop criteria include limits on concrete strain, crack width, residual deflection, load-deflection behavior, and bending moment and shear capacity. 3) Field tests of instrumented bridges found the structures did not exceed the proposed strain, crack width, deflection, or load criteria when subjected to proof loads, validating the proposed stop criteria. However, more shear tests are needed, especially on concrete slabs.

1. Challenge the future
Delft
University of
Technology
Proposed stop criteria for proof load
testing of concrete bridges and verification
Eva Lantsoght, Cor van der Veen, Dick Hordijk

2. 2
Overview
• Introduction to proof load testing
• Proposed of stop criteria
• Overview
• Theoretical bases
• Verification
• Proof load tests
• Failure tests
• Summary & Conclusions Slab shear experiments, TU Delft

3. 3
Why load testing?
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

4. 4
Proof load testing
• Target load
• Stop criteria:
• No further loading
• Failure near
• Irreversible damage near
• Bending moment AND shear?
MSc Thesis W. Vos

5. 5
Existing Guidelines for proof loading
• DAfStB Richtlinie
• Stop criteria
• Concrete strain
• Steel strain
• Crack width and residual
• Residual deflection
• Flexure
• Buildings
• Strain: arbitrary limit
• Crack width: durability

6. 6
Existing Guidelines for proof loading
• ACI 437.2M-13
• Stop criteria:
• Residual deflection
• Permanency ratio
• Deviation from Linearity
Index
• For prescribed loading
protocol

7. 7
Proposed stop criteria (1)

8. 8
Proposed stop criteria (2)
• Bending moment & shear
• Cracked & Uncracked
• w ≥ 0,05 mm
• Quant & qual
• ΔEI ≤ 25%
• Deflection profiles
• Load-deflection graph

9. 9
Proposed stop criteria – Bending
moment
• εstop ~ 0.65fy
• wstop ~ 0.65fy
, ,max 0c c bot c stop     
2
2
0.65
2
2
ym perm
stop fr c
s
f f s
w d
E

  
  
 

10. 10
Proposed stop criteria – Shear
• εstop : 800με or limit CSDT
(K. Benitez)
• wstop: % of wai: aggregate
interlock lower than inclined
cracking load
Aggregate interlock across crack

11. 11
Pilot proof load tests
• Vlijmen-Oost (with BELFA)
• effect of ASR
• Halvemaans Bridge
• flexure-critical
• Zijlweg
• effect of ASR
• De Beek
• flexure-critical
• insufficient reinforcement
Halvemaans Bridge

12. 12
Failure tests
• Ruytenschildt Bridge
• tested to failure in 2 spans
• Beams
• from Ruytenschildt Bridge
• cast in lab (plain bars)
Ruytenschildt Bridge with loading in span 2

13. 13
Verification – field tests (1)
• Field tests
• heavily instrumented
• no structural distress
• Stop criteria should not be
exceeded
Viaduct De Beek

14. 14
Verification – field tests (2)
Test ε w S LD TD
Vlijmen - bending >Fmax >Fmax >Fmax >Fmax --
Vlijmen – shear >Fmax >Fmax >Fmax >Fmax --
Halvemaans Bridge >Fmax >Fmax >Fmax Fmax >Fmax
Zijlweg – bending >Fmax >Fmax >Fmax >Fmax >Fmax
Zijlweg – shear >Fmax >Fmax >Fmax >Fmax >Fmax
De Beek – bending >Fmax >Fmax >Fmax >Fmax >Fmax
De Beek – shear >Fmax Fmax >Fmax >Fmax >Fmax

15. 15
Verification – failure tests (1)
• Margin of safety
• Need cyclic loading
• Ruytenschildt:
• span 1: no failure
• span 2: pier settlement
• Results:
• 46% - 56% of Fmax in experiments
• 62% - 65% for RSBridge Failure of P804A2

16. 16
Verification – failure tests (2)
Test Case ε w S LD TD
RB
Span 1
B + C >Fmax >Fmax 63% 62% 62%
RB
Span 2
B + C 85% 93% 79% 65% 65%
ε w S HD VD
RSB01F B + UC 53% 53% 28% - 99%‡ 54% 54%
RSB02A B + UC 46% 53% >Fmax 47% 47%
RSB02B B + UC 62% 64% 42% - Fmax 54% 54%
RSB03F B + UC 60% 62% 40% 56% 56%
RSB03A S + UC 83% 81% 55% NA 55%
P804A1 B + UC 52% 56% 58% 58% 77%
P804A2 S + C 52% 65% >Fmax 87% >Fmax
P804B S + UC 57% 88% 89% 56% 56%
P502A2 B + C 81% 52% Fmax 83% 83%

17. 17
Summary & Conclusions
• Proof load =direct assessment
• Proposal stop criteria ~ Theory
• Flexural theory
• CSDT
• Verification of criteria
• Field test: not exceeded: OK
• Failure tests: margin of safety
• But: more shear tests (+ on slabs)
necessary for validation

18. 18
Contact:
Eva Lantsoght
E.O.L.Lantsoght@tudelft.nl // elantsoght@usfq.edu.ec
+31(0)152787449