Jan 13th 2020
Challenge the future
Delft
University of
Technology
Load Rating using Load Testing:
Introducing the New Bridge Load Testing E-Circular
Sreenivas Alampalli, Dan M. Frangopol, Jesse Grimson, David Kosnik,
Marvin Halling, Eva O.L. Lantsoght, Jeff S. Weidner, David Y. Yang, Y. Edward Zhou

2Load Rating using Load Testing: Introducing the New Bridge Load Testing E-Circular
• 1998 Manual for Bridge Rating
through Load Testing
• Basis for AASHTO Manual for
Bridge Evaluation
• Need to include current state-
of-the-practice
Introduction:
Why an e-circular on load testing?
NCHRP, Manual for Bridge Rating through Load Testing. 1998: Washington, DC. p. 152.

3Load Rating using Load Testing: Introducing the New Bridge Load Testing E-Circular
Introduction to e-circular
Contents of e-circular
Chapter Title
1 Introduction
2 General Considerations
3 General load test preparation
4 Diagnostic load tests
5 Proof load tests
6 Estimating the reliability index and remaining service life
7 Illustrative examples

4Load Rating using Load Testing: Introducing the New Bridge Load Testing E-Circular
Introduction to e-circular
Objectives of a load test (1)
Diagnostic load testing Proof load testing
Lantsoght, E. O. L., Bonifaz, J., Sanchez, T. A. and Harris, D. K., 2019, "Chapter 8:
Methodology for diagnostic load testing," Load Testing of Bridges: Current practice and
Diagnostic Load Testing, Lantsoght, E. O. L., ed., Taylor & Francis, Structures and
Infrastructures, Series Editor: D.M. Frangopol.
Lantsoght, E. O. L., Koekkoek, R. T., Hordijk, D. A. and De Boer, A., 2017, "Towards
standardization of proof load testing: pilot test on viaduct Zijlweg," Structure and
Infrastructure Engineering, pp. 16.

5Load Rating using Load Testing: Introducing the New Bridge Load Testing E-Circular
Introduction to e-circular
Objectives of a load test (2)
Diagnostic load testing
• known load, fraction of design live
load
• compare analytical response to
experimental response
• develop field-validated model
• load rating based on improved
model
Proof load testing
• apply factored live load
• direct proof that bridge can carry
loads
• evaluate long-term reliability of
load-carrying mechanisms
• careful execution

6Load Rating using Load Testing: Introducing the New Bridge Load Testing E-Circular
Introduction to e-circular
Application of load tests
• Current load rating close to 1
• Multi-girder bridges
• Slab bridges
• Bridges with deterioration or damage
• Planless bridges
• Arch bridges
Lantsoght, E. O. L., Bonifaz, J., Sanchez, T. A. and Harris, D. K., 2019,
"Chapter 8: Methodology for diagnostic load testing," Load Testing of
Bridges: Current practice and Diagnostic Load Testing, Lantsoght, E. O. L.,
ed., Taylor & Francis, Structures and Infrastructures, Series Editor: D.M.
Frangopol.

7Load Rating using Load Testing: Introducing the New Bridge Load Testing E-Circular
Scope:
• Preparation
• Execution
• Analysis of load tests
Long-span bridges outside of scope
But elements can be tested according to
e-circular
Introduction to e-circular:
Scope
Lantsoght, E.O.L., et al., Proof load testing of reinforced concrete slab
bridges in the Netherlands. Structural Concrete, 2017. 18(4): p. 597-
606.

8Load Rating using Load Testing: Introducing the New Bridge Load Testing E-Circular
• Diagnostic load tests
• Parameter-specific tests
• Proof load tests
• Dynamic load allowance estimation
• Vibrational methods
General considerations:
Types of load tests

9Load Rating using Load Testing: Introducing the New Bridge Load Testing E-Circular
• Rating factor according to MBE
• Diagnostic load test: identify
LL more accurately
• Proof load test: RF entirely
• Load rating:
• diagnostic load test: with field-
verified model, adjusted for
rating
• proof load test: based on
rating vehicle weight LR and
maximum proof load LP
General considerations:
Rating Factor and Load Testing for Load Rating

10Load Rating using Load Testing: Introducing the New Bridge Load Testing E-Circular
• Gather available documentation
• Field inspection according to
MBE
• section losses
• deterioration
• Preliminary calculations
• load rating
• expected capacity
• material parameters
• analytical model
• NDE to improve model
Load testing preparation:
Preliminary structural investigation
Lantsoght, E.O.L., et al., Towards standardization of proof load testing: pilot
test on viaduct Zijlweg. Structure and Infrastructure Engineering, 2017: p. 16.

11Load Rating using Load Testing: Introducing the New Bridge Load Testing E-Circular
• Site-specific limitations 
inspection
• instrumentation plan
• load application
• site-specific safety concerns
• Preparation  test objectives
• Include interpretation of
responses
• Safety and risk analysis plan
• Planning of on-site activities
Load testing preparation:
Planning and preparation of load tests
Planning of on-site activities

12Load Rating using Load Testing: Introducing the New Bridge Load Testing E-Circular
• Instrumentation plan:
• sensor layout
• data collection plan
• mounting & wiring details
• Parameters to measure
• Include redundancy
• Data acquisition and
visualization
• Personnel requirements  local
agencies’ requirements
• Requirements for test vehicles
Load testing preparation:
Loading and instrumentation
Lantsoght, E.O.L., et al., Pilot Proof-Load Test on Viaduct De
Beek: Case Study. Journal of Bridge Engineering, 2017. 22(12):
p. 05017014.

13Load Rating using Load Testing: Introducing the New Bridge Load Testing E-Circular
Effect of temperature and humidity
• on structural response
• on sensor
Structural response:
• reference (dummy) sensor
• “no load” cases
Sensor:
• sensor selection, small sensitivity
• corrections provided by manufacturer
Load testing preparation:
Environmental effects
Koekkoek, R.T., E.O.L. Lantsoght, and D.A. Hordijk, Proof loading of the
ASR-affected viaduct Zijlweg over highway A59. 2015, Delft University of
Technology: Delft, The Netherlands. p. 180.

14Load Rating using Load Testing: Introducing the New Bridge Load Testing E-Circular
Steel bridges
• strain profiles – composite action
• strains: design assumptions, or
performance over time
Concrete bridges
• avoid risk of brittle failure
• strain profile: (un)cracked cross-
section
• larger gages, smeared cracking
• prestressed: cfr. steel bridges
Load testing preparation:
Structure type considerations (1)
Yarnold, M., T. Golecki, and J. Weidner, Identification of Composite Action
Through Truck Load Testing. Frontiers in Built Environment, 2018. 4(74).

15Load Rating using Load Testing: Introducing the New Bridge Load Testing E-Circular
Arch bridges
• stone, masonry, unreinforced concrete
• 3D load-carrying behavior
• analytical model: 3D as well
Timber bridges
• special attention to condition assessment
Long-span and signature
• more detailed preparation
Load testing preparation:
Structure type considerations (2)
Wipf, T.J., M.A. Ritter, and D.L. Wood, Evaluation and Field Load
Testing of Timber Railroad Bridge. Transportation Research
Record, 2000. 1696(Structures): p. 323-333.

16Load Rating using Load Testing: Introducing the New Bridge Load Testing E-Circular
Diagnostic load testing
Procedures (1)

17Load Rating using Load Testing: Introducing the New Bridge Load Testing E-Circular
Diagnostic load testing
Procedures (2)

18Load Rating using Load Testing: Introducing the New Bridge Load Testing E-Circular
Diagnostic load testing
Procedures (3)

19Load Rating using Load Testing: Introducing the New Bridge Load Testing E-Circular

20Load Rating using Load Testing: Introducing the New Bridge Load Testing E-Circular
Proof load testing
Procedures (1)

21Load Rating using Load Testing: Introducing the New Bridge Load Testing E-Circular
Proof load testing
Procedures (2)

22Load Rating using Load Testing: Introducing the New Bridge Load Testing E-Circular
Proof load testing
Procedures (3)

23Load Rating using Load Testing: Introducing the New Bridge Load Testing E-Circular
Proof load testing
Stop criteria
• No nonlinearity
• Define stop criteria prior to test
• Depends on
• structure type
• material
• expected failure mode
• For recommendations: refer to
literature
Lantsoght, E. O. L., Yang, Y., van der Veen, C., Hordijk, D. A. and de Boer, A.,
2019, "Stop Criteria for Flexure for Proof Load Testing of Reinforced Concrete
Structures," Frontiers in Built Environment, V. 5, No. 47, 2019-April-05.

24Load Rating using Load Testing: Introducing the New Bridge Load Testing E-Circular
Estimating reliability index and remaining service
life (1)

25Load Rating using Load Testing: Introducing the New Bridge Load Testing E-Circular
Estimating reliability index and remaining service
life (2)

26Load Rating using Load Testing: Introducing the New Bridge Load Testing E-Circular
Estimating reliability index and remaining service
life (3)

27Load Rating using Load Testing: Introducing the New Bridge Load Testing E-Circular
Estimating reliability index and remaining service
life (4)

28Load Rating using Load Testing: Introducing the New Bridge Load Testing E-Circular
Estimating reliability index and remaining service
life (5)

29Load Rating using Load Testing: Introducing the New Bridge Load Testing E-Circular
Examples
• Full example of diagnostic load test
• Full example of proof load test
• Summarized case studies (3)
• List of suggested further reading

30Load Rating using Load Testing: Introducing the New Bridge Load Testing E-Circular
Summary and conclusions
New e-circular: Primer on Bridge Load Testing
Practical document
Advice on load testing:
• Preparation
• Execution
• Analysis
& new concepts:
• Field-verified analytical model
• Rating after proof load testing
• Determination of reliability index

31Load Rating using Load Testing: Introducing the New Bridge Load Testing E-Circular
Contact:
Eva Lantsoght
E.O.L.Lantsoght@tudelft.nl
elantsoght@usfq.edu.ec