Optimizing Steel Railway Truss Bridge Health Monitoring

University of Nebraska - LincolnDigitalCommons@University of Nebraska - LincolnCivil Engineering Theses, Dissertations, andStudent Research Civil Engineering

4-2017

Optimizing Steel Railway Truss Bridge HealthMonitoringAhmed RagehUniversity of Nebraska-Lincoln, a.eissa.rageh@huskers.unl.edu

Daniel LinzellUniversity of Nebraska-Lincoln, dlinzell@unl.edu

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Rageh, Ahmed and Linzell, Daniel, "Optimizing Steel Railway Truss Bridge Health Monitoring" (2017). Civil Engineering Theses,Dissertations, and Student Research. 104.http://digitalcommons.unl.edu/civilengdiss/104

Ahmed Rageh (MS), Daniel Linzell (Ph.D., P.E., F. ASCE) – University of Nebraska-Lincoln

Model Calibration

• Model:ü3D frame model PLUSüRails/tiesüGeometric offsets, connections

Bridge Under Study

• Multi-Span Steel Through-TrussüDouble-TracküRiveted ConstructionüEyebars

• Condition Foci:üStringer-to-floor beam connectionsüStringer and truss bottom lateralsüEyebarsüBearings

Objectives

Problems – Condition Evaluation

• Visual inspection:üPrescribed frequencyüCostlyüSubjected to human interpretation

• Sensors:üFocused on a single bridgeüExtensive arrayüCostly

Analysis Based Health Monitoring Plan

Problems - Steel Railway Trusses

• Aging• Large system – bridge AND railway• Labor intensive condition eval• Reported conditions:üStringer-to-floor beam connections

[Haghani 2012]üStringer flange clip angle cracks

[Haghani 2012]üUnequal eyebars stress

distribution [DelGrego 2008]üDisplaced eyebar pins [DelGrego 2008]

Conclusions, Future Work• Validated model - published test results• Field tests/model calibration – SHM

planning• Proposed SHM plans• Validated SHM plans - field monitoring

• Sensitivity Analyses:üModified models - mimic reported

condition - 20 modelsüE.G. – cracked connection

Stringer-to-floor beamconnection

Stringer flange clipAngle

Hea

lth m

onito

ring

syst

em

Initial steps

Initial field testing instrumentation planning

Initial field testing, model calibration

Final steps

Analysis based health monitoring plans

Verify analysis based health monitoring plans via testing

30’-6

”

Samples

• Initial field testing plan:

Initial Field Testing

Truss

Flooring system

Bracing system

Rails

Ties

Bot. lat. -11.25”

Str. 18.75”

FB18.75”

Truss bot.0.00”

Str. lat.24.00”

5.70

4.793.943.82

5.345.22

-4.0

0.0

4.0

8.0

6 7 8 9 10

Stre

ss (k

si)

Time (Sec)

Stringer mid-span bottom stresses

Field Results (B4519) Field Results (B4520)Model Results (B4519) Model Results (B4520)

1.16

Assumed conditions

• Proposed health monitoring plan:ü~2200 permutations ü3 proposed plans

-1.5

0.0

1.5

3.0

8 9 10 11 12 13

Stre

ss (k

si)

Time (Sec)

Stringer #1 end-span bottom stressesField Results (B4539) Model Results (B4539) Defected

Stress reduced