testing of concrete sleepers and fastener systems for the ... · • collect data to validate the...

Justin Grassé, David Lange

Presenter: Marcus Dersch

10th International Heavy Haul Association Conference

New Delhi, India

6 February 2013

Testing of Concrete Sleepers and Fastener Systems

for the Understanding of Mechanistic Behavior

Testing of Concrete Sleepers and Fastener Systems for the Understanding of Mechanistic Behavior

Outline • Background

• UIUC Concrete Sleeper Research

Overview

• Objectives of Field Research

• Field Instrumentation Strategy

• Testing at Transportation Technology

Center (TTC)

– Pueblo, CO, USA

• Experimental Results

• Findings

• Future Work


Fastening System Components

Rail Pad

Assembly

Clip

Insulator

Concrete Crosstie

Shoulder

Rail


2012 International Survey Results Criticality of Problems – North American Responses

Failure Mode Average Rank

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/chemical degradation 3.50

Research Topic Average Rank

Prevention or repair of rail seat deterioration 3.60

Fastening system design 3.60

Materials design 3.00

Optimize crosstie design 2.80

Track system design 2.00

Railway Engineering and UIUC Research Overview

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


Research Sponsors and

Projects • CN Fellowship in Rail Engineering (RSD)

• Association of American Railroads (AAR)

Technology Scanning Program (RSD and

Fastening System Wear and Fatigue)

• Amsted RPS / Amsted Rail, Inc.

(Fastening System Wear and Fatigue)

• NEXTRANS Region 5 Transportation

Center (RSD)

• Federal Railroad Administration (FRA)

(Fastening System Wear and Fatigue,

Cracking, Environmental, etc.)

• National University Rail (NURail)

(Fastening System Wear and Fatigue)

National University Rail Center

http://www.aar.org/


Comprehensive

Literature Review

International Tie and

Fastening System Survey

Loading Regime (Input)

Study

Rail Seat Load

Calculation

Methodologies

Involvement of Industry

Experts

Comprehensive

Literature Review

International Tie and

Fastening System Survey

Loading Regime (Input)

Study

Rail Seat Load

Calculation

Methodologies

Involvement of Industry

Experts

Data Collection

Document Depository

Groundwork for

Mechanistic Design

International Survey Report

Load Path Map

Parametric Analysis

State of Practice Report

Validated Tie and

Fastening System Model

Data Collection

Document Depository

Groundwork for

Mechanistic Design

International Survey Report

Load Path Map

Parametric Analysis

State of Practice Report

Validated Tie and

Fastening System Model

Laboratory

Study

Modeling

Field

Study

Impro

ved R

ecom

mend

ed P

ractic

es

Laboratory

Study

FRA Tie and Fastener Project Structure

Inputs Outputs/Deliverables


• Lay groundwork for mechanistic design of concrete

sleepers 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 sleeper and

fastening system FE model

Goals of Field Instrumentation


Areas of Investigation Fasteners/ Insulator

• Strain of fasteners

• Stresses on insulator

• Moments at the

rail seat

• Stresses at rail seat

• Vertical

displacements of

sleepers

Concrete Sleepers

Rail

• Stresses at rail seat

• Strains in the web

• Displacements of web/base


2012 Field Instrumentation Map • Full Instrumentation

– Lateral, vertical, and chevron strain gauges on rail

– Embedment and external concrete strain gauges on crosstie

– Matrix based tactile surface sensors at rail seat (at rail seat W)

– Linear potentiometers on rail and crosstie

• Partial Instrumentation

– Vertical strain gauges on rail

– Matrix based tactile surface sensors (at rail seats G and Y)

– Linear potentiometers on crosstie (at rail seats C and G)


Field Instrumentation Locations

• TTC (Pueblo, CO, USA)

• High Tonnage Loop (HTL)

– Curve (~5°)

– Safelok I Fasteners


Field Instrumentation Locations

• TTC (Pueblo, CO, USA)

• Railroad Test Track (RTT)

– Tangent

– Safelok I Fasteners


Loading Environment

• Track Loading Vehicle (TLV)

– Static

– Dynamic

• Freight Consist

– 6-axle locomotive

• 30t axles (393 GRL)

– Instrumented car

– Nine cars

• 30, 33, and 36t axles

(263, 286, 315 GRL cars)

• Passenger Consist

– 4-axle locomotive

• 29t axles (255 GRL)

– Nine coaches

• 10t axles (87 GRL cars)


Fully Instrumented Rail Seats

Instrumented

Low Rail


Instrumented Low Rail


Field-side Instrumentation

Vertical Sleeper

Displacement

Base Displacement

Vertical Web

Strain

Clip Strain


Gauge-side Instrumentation

Lateral Rail

Displacement


Data Acquisition System


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 Acting on a Tangent Track

Lateral

Loads

Max

Median Lower quartile

Upper quartile

Leading axles of a 10-car freight

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

Minimum

Left Right

Tangent


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 Acting on a Tangent Track

Lateral

Loads

- No correlation

between lateral loads

and train speed on

tangent track.



Left Right

Tangent


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.


Variability in Loading Conditions

0 1 2 3 4 5 6

0

10

20

30

40

50

60

70

80

0

50

100

150

200

250

300

350

400

0 5 10 15 20 25 30

Lateral Load (kips)

Ver

tica

l Lo

ad (

kip

s)

Ver

tica

l Lo

ad (

kN)

Lateral Load (kN)

97 km/h, 60mph

24 km/h, 15mph

- Negligible correlation between lateral

and vertical loads on tangent track.


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)

Ve

rtic

al T

ie D

eflection (

in)

Ve

rtic

al S

leeper

De

flection (

cm

)

Speed (km/h)

Freight

Passenger

Negligible correlation between

train speed and sleeper deflection

Effect of Train Speed on Sleeper

Displacement


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 Sle

eper

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: about

60% (passenger) and 75% (freight)

Effect of Train Speed on Sleeper

Deflection (cont.)


0 10 20 30 40

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

Rail Seat Load (kips)

Ver

tica

l Dis

pla

cem

ent

(in

)

Ver

tica

l Dis

pla

cem

ent

(cm

)

Rail Seat Load (kN)

Variability in Support Conditions

• Curve/Static Loads

• Each point = +22kN (+5kips) vertical load

• Low rail: weak support (slack or gap in support system)

• Low rail seat forces

• High rail: stiff boundary conditions (well-supported)

• High rail seat forces

HIGH LOW


0 10 20 30 40

0

5

10

15

20

25

30

35

40

0

20

40

60

80

100

120

140

160

180

200

0 50 100 150

Vertical Load (kips)

Rai

l Sea

t Lo

ad (

kip

s)

Rai

l Sea

t Lo

ad (

kN)

Vertical Load (kN)

Variability in Support Conditions

Nearly 95% of load is

transferred to rail seat

With a weak substructure much of the vertical load

(over 75%) is transferred to adjacent sleepers and resisted

by the bending of the rail

HIGH LOW


Preliminary Findings with

Potential Design Considerations • The lateral loading demands were 5.5 times higher in the curve

than on tangent track

– Design should consider specialized components in the curve

• The vertical and lateral loading demands on tangent track are not

dependent on train speed

– Design should not weight speed highly on tangent track

• There is negligible correlation between concurrently acting lateral

and vertical loads on tangent track

• Dynamic vertical sleeper displacement never exceeded the purely

static response

• Rail seat forces are highly dependent on the stiffness of the

substructure and support conditions and can range from

below 20% to over 90% of the wheel-rail load

– Design should incorporate probabilistic loading conditions


Future Work • 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 sleepers

– pressure magnitude and distribution at the rail seat

• Continued comparison and validation of the UIUC finite

element model (Chen, Shin)

• Preparation for instrumentation trip (Summer 2013)

– Focus on lateral load path by gathering

• relative lateral sleeper displacements

• global lateral sleeper displacements

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

• Small-scale, evaluative tests on Class I Railroads


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

• Vince Peterson, Pelle Duong, George Righter

• Monticello Railway Museum (Tim Crouch)

• Transportation Technology Center, Inc.

– Dave Davis, Ken Laine, Dingqing Li, Steve Luna

• For assistance in instrumentation preparation:

– Harold Harrison, Michael Tomas, Jacob Henschen, Thomas Frankie

FRA Tie and Fastener BAA

Industry Partners:


Questions?

Marcus Dersch

Department of Civil and Environmental Engineering

University of Illinois, Urbana-Champaign

Email: [email protected]

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