experimentation and modeling of concrete crossties and … · 2019. 1. 18. · • found in arema...

1

Experimentation and Modeling of Concrete Crossties and Fastening Systems

Wheel Rail Interaction Conference

8-9 May 2013

Chicago, IL USA

J. Riley Edwards and Brandon Van Dyk

2

Outline

• Background and Research Justification

• RailTEC Concrete Crosstie Research

• Mechanistic Design Introduction

• Key Research Thrust Areas and

Summary of Results

– Laboratory Instrumentation

– Field Instrumentation

– Analytical Methods (FEA)

• Future Work

• Acknowledgements

3

Outline• Background and Research Justification




Summary of Results




• Future Work


4

Concrete Crossties – Overview of Use

• Typical Usage:

– Freight Heavy tonnage

lines, steep grades, and

high degrees of curvature

– Passenger High density

corridors (e.g. Amtrak’s

Northeast Corridor [NEC])

– Transit applications

• Number of concrete ties in

North America*:

– Freight 25,000,000

– Passenger 2,000,000

– Transit Significant

quantities (millions)

*Approximate

5

Rail

GaugeField

Concrete

crosstie

ShoulderShoulder

ClipClip Insulator

Insulator

Rail pad

assembly

Fastening System Components

6

Complete System

8-9 ft

56.5 in

8-13 in

6-10 inPrestress

wire or strand

Insulator

Clip

Shoulder insert Tie pad between

rail base and

rail seat

7





Summary of Results




• Future Work


8

Concrete Crosstie and Fastener

Research Levels (and Examples)

Materials

Concrete Mix

Design

Rail Seat Surface

Treatments

Pad / Insulator Materials

Components

Fastener Yield Stress

Insulator Post Compression

Concrete

Prestress Design

System

Finite Element Modeling

Full-Scale Laboratory

Experimentation

Field Experimentation

9

2012 International Survey Results – Criticality of Problems

Problem (higher ranking is more critical) Average Rank

International Responses

Tamping damage 6.14

Shoulder/fastening system wear or fatigue 5.50

Cracking from center binding 5.36

Cracking from dynamic loads 5.21

Cracking from environmental or chemical degradation 4.67

Derailment damage 4.57

Other (e.g. manufactured defect) 4.09

Deterioration of concrete material beneath the rail 3.15

North American Responses

Deterioration of concrete material beneath the rail 6.43

Shoulder/fastening system wear or fatigue 6.38

Cracking from dynamic loads 4.83

Derailment damage 4.57

Cracking from center binding 4.50

Tamping damage 4.14

Other (e.g. manufactured defect) 3.57

Cracking from environmental or chemical degradation 3.50

10

Outline





Summary of Results




• Future Work


11

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

12

Principles of Mechanistic Design

1. Quantify track system input loads (wheel loads)

2. Qualitatively establish load path (free body diagrams, basic

modeling, etc.)

3. Quantify demands on each component

a. Laboratory experimentation

b. Field experimentation

c. Analytical modeling

4. Link quantitative data to component geometry and materials

properties (materials decision)

5. Relate loading to failure modes

6. Investigate interdependencies through modeling

7. Establish mechanistic design practices and incorporate into

AREMA Recommended Practices

13

Determining System Input Loads

• Quantitative methods of data collection (Step 1):

– Wheel Impact Load Detectors (WILD)

– Instrumented Wheel Sets (IWS)

– Truck Performance Detectors (TPD)

– UIUC Instrumentation Plan (FRA Tie BAA)

• Most methods above are used to monitor rolling stock

performance and assess vehicle health

• Can provide insight into the magnitude and

distribution of loads entering track structure

– Limitations to WILD: tangent track (still need lateral

curve data), good substructure (not necessarily

representative of the broader rail network)

14

Vertical Wheel Loads – Shared Infrastructure

Source: Amtrak – Edgewood, MD (November 2010)

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 5 10 15 20 25 30 35 40 45 50 55 60

Pe

rce

nt

Ex

ce

ed

ed

Nominal Vertical Load (kips)

Freight LocomotivesIntermodal Freight CarsPassenger CoachesPassenger LocomotivesOther Freight Cars

Empty

Cars

Loaded

Cars

15

UNLOADED FREIGHT CARS

PASSENGER COACHES

LOADED FREIGHT CARS


Effect of Traffic Type on Peak Wheel Load

16

Talbot/Hay

Dynamic Wheel Load Factors


Talbot/Hay

Indian Railways

Talbot/Hay

Indian Railways

Eisenmann

Talbot/HayIndian RailwaysEisenmannBirmannAREMA Chapter 30

Speed Factor

17

More than a Dynamic Factor: Impact Factor

0.4%

𝑰𝒎𝒑𝒂𝒄𝒕 𝑭𝒂𝒄𝒕𝒐𝒓 (𝑰𝑭) =𝑷𝒆𝒂𝒌 𝑳𝒐𝒂𝒅

𝑺𝒕𝒂𝒕𝒊𝒄 𝑳𝒐𝒂𝒅

Source: UPRR – Gothenburg, NE (January 2010)

18

So What is Our Design Threshold?

Fre

qu

en

cy

Load (e.g. Rail Seat Load)

Threshold #2Threshold #1

*Need curves for each component / interface and failure mode

19

Development of Quantitative Loading Model

Speed

Pe

ak V

ert

ica

l W

he

el L

oa

d

Confidence

interval

20

Locomotives

Development of Quantitative Loading ModelConceptual Sketch

Nominal Vertical Wheel Load

Pe

ak V

ert

ica

l W

he

el L

oa

d 286kFreight

Car (Load)

315k

Freight

Car(Load)

Pass.

Coach 1

Pass.

Coach 2

286k

Freight

Car (Empty)

315k

Freight

Car(Empty)

21

Establishment of the Qualitative Load Path

22

Rail Seat Load Calculation Methodologies

0 5 10 15 20 25 30 35 40 45 50 55

0

2

4

6

8

10

12

14

16

18

20

22

0

10

20

30

40

50

60

70

80

90

100

0 25 50 75 100 125 150 175 200 225 250

Wheel Load (kips)

Ra

il S

ea

t L

oa

d (

kip

s)

Ra

il S

ea

t L

oa

d (

kN

)

Wheel Load (kN)

AREMA

USACE

Average

Kerr

Talbot

Analysis courtesy of Christopher Rapp

23

Outline





Summary of Results




• Future Work


24

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 crossties and fastening system design in the

US

• Program Deliverables

– Improved mechanistic design recommendations for

concrete crossties and fastening systems in the US

– Improved safety due to increased strength of critical

infrastructure components

– Centralized knowledge and document depository for

concrete crossties and fastening systems

FRA Tie and Fastener BAA

Industry Partners:

25

Quantification of Lateral Loads Entering

the Shoulder Face (Insert)• Instrumented shoulder face insert

– Original shoulder face is removed

– Small beam insert replaces removed section

– 4-point bending beam experiment

• Beam strategy is a well-established, successful technology

26

Transfer of Lateral Load to Shoulder Face32.5 kip vertical load, 0.5 L/V ratio

Time (Seconds)

27

Percent of Lateral Load Transferred to ShoulderPreliminary Data

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Full Scale Track Response Experimental System

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Full Scale Track Response Experimental System

30

Outline





Summary of Results




• Future Work


31

• Lay groundwork for mechanistic design of concrete

crossties and elastic fasteners

• Quantify the demands placed on each component within

the system

• Develop an understanding into field loading conditions

• Provide insight for future field testing

• Collect data to validate the UIUC concrete crosstie and

fastening system FE model

Goals of Field Instrumentation

32

Areas of InvestigationFasteners/ Insulator

• Strain of fasteners

• Stresses on insulator

• Moments at the

rail seat

• Stresses at rail seat

• Vertical

displacements of

crossties

Concrete Crossties

Rail

• Stresses at rail seat

• Strains in the web

• Displacements of web/base

33

TTCI Field Testing Locations

5 degree curve spiral

Balance Speed = 33 mph

Tangent

Speeds up to 105 mphRailroad Test

Track (RTT)

High-Tonnage Loop (HTL)

34

Loading Environment

• Track Loading Vehicle (TLV)

– Static

– Dynamic

• Track modulus

• Freight Consist

– 6-axle locomotive (393k)

– Instrumented car

– Nine cars

• 263, 286, 315 GRL Cars

• Passenger Consist

– 4-axle locomotive (255k)

– Nine coaches

• 87 GRL

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Fully Instrumented Rail Seats

Instrumented

Low Rail

36

Instrumented Low Rail

37

Field-side Instrumentation

Vertical Tie

Displacement

Base Displacement

Vertical Web

Strain

Clip Strain

38

Gauge-side Instrumentation

Lateral Rail

Displacement

39

Data Acquisition System

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Tangent Track (RTT) – Passenger Train

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0

2

4

6

8

10

12

14

16

18

0

10

20

30

40

50

60

70

80

24 (15) 48 (30) 66 (45) 97 (60)

Late

ral Load (

kip

s)

Late

ral Load (

kN

)

Train Speed, km/h (mph)

Lateral Loads on Tangent Track (Freight)

Lateral

Loads

Max

MedianLower quartile

Upper quartile

Leading axles of a 10-car freight

train (30, 33, and 36t axle loads).

Minimum

Left Right

Tangent

42

0

2

4

6

8

10

12

14

16

18

0

10

20

30

40

50

60

70

80

24 (15) 48 (30) 66 (45) 97 (60)

Late

ral Load (

kip

s)

Late

ral Load (

kN

)


Lateral Loads on Tangent Track (Freight)

Lateral

Loads

- No correlation

between lateral loads

and train speed on

tangent track.



Left Right

Tangent

43

RTT Curved Instrumentation – Train Pass

44

Lateral Loads Acting on a Curve Track

HIGH LOW

Lateral

Loads

5°curve



0

2

4

6

8

10

12

14

16

18

0

10

20

30

40

50

60

70

80

3 (2) 24 (15) 48 (30) 66 (45)

Late

ral Load (

kip

s)

Late

ral Load (

kN

)


- Median load is ~5.5

times larger than

what was recorded in

tangent track.

45

Global Track Deflections Under

Passage of Freight Train

46

Vertical Displacements of Crossties (HTL)

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0 10 20 30 40

Ver

tica

l Dis

pla

cem

ent

(in

)

Vertical Load (kips)

HIGH

LOW

U

S

W

E

C

G

47

0 20 40 60 80 100

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0 50 100 150

Speed (mph)

Vert

ical T

ie D

eflection (

in)

Vert

ical T

ie D

eflection (

cm

)

Speed (km/h)

Freight

Passenger

No significant relationship between

train speed and tie deflection

Effect of Train Speed on Tie Deflection

48

0 10 20 30 40 50 60

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0 50 100 150 200 250 300

Vertical Load (kips)

Ver

tica

l Tie

Def

lect

ion

(in

)

Ver

tica

l Tie

Def

lect

ion

(cm

)

Vertical Load (kN)

24 km/h (15mph)

48 km/h (30mph)

97 km/h (60mph)

100% (Static Deflection)

90%

80%

60%

70%

50%

Deflections from train passes do not

exceed static response: typically

60% (passenger) and 75% (freight)

Effect of Load on Tie Deflection

49

Outline





Summary of Results




• Future Work


50

Concrete Crosstie and Fastening System

Rail

Concrete Crosstie

ClipInsulator

Shoulder

Pad &

Abrasion

frame

51

Component Modeling: Validation• Clip Model

Mises stress contour

(Clamping force = 11.6 kN) Clamping force-displacement curves

Stress concentration due

to support 0

5,000

10,000

15,000

20,000

25,000

30,000

35,000

0 0.01 0.02 0.03 0.04Rail

seat

Cla

mp

ing

fo

rce (

N)

Displacement (m)

Clip ModelManufacturer Data

52

Static loading of the model

Deformation contour

Component Modeling: Concrete Crosstie

and Ballast

53

System Model: Multiple-Tie Modeling

• Track loading vehicle (TLV) applying vertical and lateral loads to the track

structure in field

• The symmetric model including 5 crossties

Simplified model:

Fastening system were replaced

by BCs and pressure

Detailed model with the fastening system

54

System Modeling: Lateral Load Path

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40

Forc

e (

lb)

L/V Ratio

Friction (F1)

Insulator

Post (F2)

Lateral

Load

Friction + Insulator Post

+Shoulder to Pad

Shoulder

to Pad

(F3)

F1F3

F2

Lateral Load

36 Kip

Vertical Load

55





Summary of Results




• Future Work


56

Current Research Thrust Areas

• Continued data analysis to understand the governing mechanics

of the system by investigating the:

– elastic fastener (clamp) strain response

– number of ties effected simultaneously

– bending modes of the crossties

– pressure magnitude and distribution at the rail seat

• Continued comparison and validation of the UIUC tie and

fastening system finite element model (Chen, Shin)

• Preparation for instrumentation trip (May 2013)

– Focus on lateral load path by gathering

• relative lateral tie displacements

• global lateral tie displacements

• load transferred to the clip, insulator-post, and shoulder

• Small-scale, evaluative tests on Class I Railroads

57

RailTEC Concrete Tie Research Team

• Previous Personnel

– 3 Graduate Research Assistants

– 6 Undergraduate Research Assistants

• Current Personnel

– 9 Graduate Research Assistants

– 1 Postdoctoral Researcher

– 6 Undergraduate Research Assistants

– 2 Research Engineers

– 5 Faculty

58

Acknowledgements

FRA Tie and Fastener BAA Industry Partners:

National University Rail Center

Research Sponsors:

http://www.aar.org/

59

Other Supporting Organizations

60

Questions?

Riley Edwards

Senior Lecturer

Department of Civil and

Environmental Engineering

University of Illinois, Urbana-Champaign

Email: [email protected]

Brandon Van Dyk

Graduate Research Assistant

Department of Civil and

Environmental Engineering

University of Illinois, Urbana-Champaign

Email: [email protected]

experimentation and modeling of concrete crossties and … · 2019. 1. 18. · • found in arema...

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