considerations for mechanistic design of concrete sleepers and … · 2019. 1. 18. · brandon van...
TRANSCRIPT
Brandon Van Dyk, J. Riley Edwards, Conrad Ruppert, Jr., and Christopher P.L. Barkan
10th International Heavy Haul Conference New Delhi, India
4-6 February 2013
Considerations for Mechanistic Design of Concrete Sleepers and Elastic Fastening Systems
in North America
Slide 2 Quantifying Loads and Developing Mechanistic Design Practices
Outline • Background
• Principles of Mechanistic Design
• Shared Use Loading Environment
• Load Quantification Efforts
– Field Instrumentation
– Laboratory Instrumentation
– Analytical Methods
• Conclusions
• Acknowledgements
Slide 3 Quantifying Loads and Developing Mechanistic Design Practices
FRA Tie and Fastening System BAA Objectives and Deliverables • Program Objectives
– Conduct comprehensive international literature review and state-of-the-art assessment for design and performance
– Conduct experimental laboratory and field testing, leading to improved recommended practices for design
– Provide mechanistic design recommendations for concrete sleepers and fastening system design in the US
• Program Deliverables
– Improved mechanistic design recommendations for concrete sleepers and fastening systems in the US
– Improved safety due to increased strength of critical infrastructure components
– Centralized knowledge and document depository for concrete sleepers and fastening systems
FRA Tie and Fastener BAA Industry Partners:
Slide 4 Quantifying Loads and Developing Mechanistic Design Practices
Current Design Process • Found in AREMA Manual on Railway Engineering
• Based largely on practical experience:
– Lacks complete understanding of failure mechanisms and their causes
– Empirically derives loading conditions (or extrapolates existing relationships)
• Can be driven by production and installation practices
• Improvements are difficult to implement without understanding complex loading environment
Slide 5 Quantifying Loads and Developing Mechanistic Design Practices
Pavement Example of Mechanistic Design “Mechanistic Interpretation of Nondestructive Pavement Testing Deflections”, 1981 • Exploration of factors affecting pavement response to
various loading regimes
• Material properties measured from laboratory and backcalculated from system testing agree
– Can be used for asphalt concrete overlay design
• ILLI-PAVE: stress dependent finite element model used to interpret measured deflections
Applicable to the rail industry?
Source: M.S. Hoffman & M.R. Thompson
Slide 6 Quantifying Loads and Developing Mechanistic Design Practices
Principles of Mechanistic Design 1. Quantify track system input loads (wheel loads)
2. Qualitatively establish load path (free body diagrams, basic modeling, etc.)
– Establish the locations for load transfer
3. Quantify loading conditions at each interface / component (including displacements)
a. Laboratory experimentation
b. Field experimentation
c. Analytical modeling (basic → complex/system)
4. Link quantitative data to component geometry and materials properties (materials decision)
Slide 7 Quantifying Loads and Developing Mechanistic Design Practices
Principles of Mechanistic Design (cont.) 5. Relate loading to failure modes (e.g., how does
lateral loading relate to post insulator wear?)
6. Investigate interdependencies through modeling
7. Run parametric analyses
– Materials, geometry, load location
8. Development and testing of innovative designs
– Novel rail pad, sleeper, insulator designs
– Geometry and materials improvements
9. Establish mechanistic design practices
10. Adoption into AREMA Recommended Practices
Slide 8 Quantifying Loads and Developing Mechanistic Design Practices
1. Quantifying System Input Loads • Methods of data collection:
– Wheel Impact Load Detectors (WILD)
– Instrumented Wheel Sets (IWS)
– Truck Performance Detectors (TPD)
– UIUC Instrumentation Plan (FRA Tie BAA)
• Most methods are used to monitor rolling stock performance and assess vehicle health
• Can provide insight into the magnitude and distribution of loads entering track structure
Slide 9 Quantifying Loads and Developing Mechanistic Design Practices
Wheel Impact Load Detectors (WILD)
Slide 10 Quantifying Loads and Developing Mechanistic Design Practices
0 25 50 75 100 125 150 175 200 225 250 275 300
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70
Peak Vertical Load (kN)
Perc
ent E
xcee
ded
Peak Vertical Load (kips)
LocomotivesPassenger CoachesFreight WagonsAll Wheels
Vertical Wheel Loads – Edgewood, MD
Source: Amtrak – November 2010
90%
Slide 11 Quantifying Loads and Developing Mechanistic Design Practices
UNLOADED FREIGHT WAGONS
PASSENGER COACHES
LOADED FREIGHT WAGONS
Source: Amtrak – Edgewood, MD (November 2010)
Effect of Traffic Type on Peak Wheel Load
Slide 12 Quantifying Loads and Developing Mechanistic Design Practices
Effect of Wheel Condition on Peak Wheel Load
Source: Amtrak – Mansfied, MA (November 2010) Passenger Coaches
Slide 13 Quantifying Loads and Developing Mechanistic Design Practices
Impact Loads – Mansfield, MA
Source: Amtrak – November 2010
0.5%
𝑰𝑰𝑰𝑰𝑰𝑰 𝑭𝑰𝑰𝑰𝑭𝑭 (𝑰𝑭) =𝑷𝑷𝑰𝑷 𝑳𝑭𝑰𝑳𝑺𝑰𝑰𝑰𝑺𝑰 𝑳𝑭𝑰𝑳
Slide 14 Quantifying Loads and Developing Mechanistic Design Practices
Other Factors Affecting Wheel Loads • Speed
• Temperature and moisture
• Position within the train
• Curvature
• Grade
• Track quality Instrumented Wheel Set
Truck Performance Detector
UIUC Instrumentation Plan
Need alternative data collection methods
Slide 15 Quantifying Loads and Developing Mechanistic Design Practices
Rail Seat Load Calculation Methodologies
0 5 10 15 20 25 30 35 40 45 50 55
0
2
4
6
8
10
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20
22
0
10
20
30
40
50
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0 25 50 75 100 125 150 175 200 225 250
Wheel Load (kips)
Rai
l Sea
t Loa
d (k
ips)
Rai
l Sea
t Loa
d (k
N)
Wheel Load (kN)
AREMAUSACEAverageKerrTalbot
Analysis courtesy of Christopher Rapp
Slide 16 Quantifying Loads and Developing Mechanistic Design Practices
2. Establishment of the Qualitative Load Path
• Development of a static load path map for entire concrete sleeper and fastening system
• Identification and classification of all forces acting on and internal forces within each component
• Helps understand demands on each component
• Identification of component interactions
• Development of component relationships
Slide 17 Quantifying Loads and Developing Mechanistic Design Practices
2. Establishment of the Qualitative Load Path
Slide 18 Quantifying Loads and Developing Mechanistic Design Practices
3. Quantifying Loads: Instrumentation Fasteners/ Insulator
• Strain of fasteners
• Stresses on insulator
• Internal strains
– Midspan
– Rail Seat
• Stresses at rail seat
• Global displacement of the sleeper
Rail • Stresses at rail seat • Strains in the web • Displacements of head/base
Concrete Sleepers
Slide 19 Quantifying Loads and Developing Mechanistic Design Practices
3a. Laboratory Instrumentation • Development and refinement of field instrumentation
• Research with controlled variables to investigate
– Displacement of rail and fastening system components
– Pressure distribution under different L/V ratios, support conditions, and fastening system components
– The effect of dynamic load
• Make recommendations to refine future laboratory tests
Slide 20 Quantifying Loads and Developing Mechanistic Design Practices
3b. Field Instrumentation Monticello Railway Museum – Fall 2011 • Proof of concept for
future field experimentation
Transportation Technology Center (TTC) – July 2012 • Seven consecutive
sleepers instrumented
• Tangent and curve sections
• Additional testing at TTC – May 2013
Slide 21 Quantifying Loads and Developing Mechanistic Design Practices
3c. Quantifying Loads: Finite Element Modeling • Component models to provide reference for lab and
field experimental efforts
• Detailed structural model for conducting parametric analyses on materials and geometries of components
• System model to understand component interactions
Cla
mpi
ng F
orce
Displacement
Manufacturer’s Curve UIUC Model
Slide 22 Quantifying Loads and Developing Mechanistic Design Practices
0
5,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
0 0.1 0.2 0.3 0.4 0.5
Forc
e (N
)
L/V Ratio
3c. System Modeling: Lateral Load Path
Friction (F1) Insulator Post (F2)
Lateral Load
Friction + Insulator Post +Shoulder to Pad
Shoulder to Pad (F3)
Lateral Load
F1F3
F2
80 kN Vertical Load
Slide 23 Quantifying Loads and Developing Mechanistic Design Practices
Conclusions • Passenger and freight loads on shared infrastructure
can cause divergent design recommendations due to varied loading
– Quantification of loads is critical in improving design and performance of infrastructure
– Component interaction must be well understood for adequate design methodologies
• Mechanistic design provides a framework for improved recommended design practices
• Ultimate objective: increase safety and lower life cycle costs of the concrete sleeper and fastening system
Slide 24 Quantifying Loads and Developing Mechanistic Design Practices
Acknowledgements
• Funding for this research has been provided by the Federal Railroad Administration (FRA)
• Industry Partnership and support has been provided by – Union Pacific Railroad – BNSF Railway – National Railway Passenger Corporation (Amtrak) – Amsted RPS / Amsted Rail, Inc. – GIC Ingeniería y Construcción – Hanson Professional Services, Inc. – CXT Concrete Ties, Inc., LB Foster Company
• For assistance in data acquisition – Steve Crismer, Jonathan Wnek (Amtrak)
• For assistance in data processing and interpretation – FRA Tie and Fastener BAA Team (UIUC) – Andrew Stirk, Anusha Suryanarayanan (UIUC)
FRA Tie and Fastener BAA Industry Partners:
Slide 25 Quantifying Loads and Developing Mechanistic Design Practices
Questions
Brandon Van Dyk Graduate Research Assistant e-mail: [email protected]
Conrad Ruppert, Jr.
Senior Research Engineer e-mail: [email protected]
J. Riley Edwards Senior Lecturer
e-mail: [email protected]
Christopher P.L. Barkan Professor
e-mail: [email protected]
Rail Transportation and Engineering Center – RailTEC University of Illinois at Urbana-Champaign