Mechanistic Design of Rail Transit Concrete Crossties ... · •Fully seated passenger load + AW0 –AW2 (Design Load) ... Aircraft Weight and Balance Control. ... 0 50 100 150 200

Slide 1Mechanistic Design of Rail Transit Concrete Crossties

Mechanistic Design of Concrete Monoblock

Crossties for Rail Transit Loading Conditions

APTA Rail Conference

Salt Lake City, UT

23 June, 2015

Matthew V. Csenge, Xiao Lin, Henry E. Wolf, Marcus S. Dersch, and J. Riley Edwards


Mechanistic Design of Concrete Monoblock

Crossties for Rail Transit Loading Conditions

2015 APTA Rail Conference

Salt Lake City, UT

23 June 2015

Matthew V. Csenge, Xiao Lin, Henry E. Wolf, Marcus S. Dersch,

J. Riley Edwards and Christopher P.L. Barkan


• Background and Motivation

• Project Introduction

– Mission and Objectives

– Methods and Technologies

– Industry Partners and Potential Field

Experimentation Locations

• Introduction to Mechanistic Design

• Load Environment

• Transit Focused Concrete Crosstie

Flexural Analysis

• Future Work

Outline


• Mission:

– Characterize the desired performance requirements for

concrete crossties and fastening systems for rail transit

– Quantify the behavior of these systems under load

– Develop resilient infrastructure component design solutions

for concrete crossties and fastening systems for rail transit

• Objectives:

– Investigate field performance demands on concrete crossties

and fastening systems for rail transit applications

– Develop an analytical finite element model

– Validate analytical model and further field research through

lab experimentation

– Develop mechanistic design recommendations for rail transit

applications of concrete crossties and fastening systems

Project Mission and Objectives


• American Public Transportation

Association (APTA)

• MTA New York City Transit

(NYCT)

• MetroLink

• Metra

• TriMet

• CXT Concrete Ties, Inc.

• GIC

• Pandrol USA

• Amsted RPS

• Hanson Professional Services, Inc.

• Amtrak

FTA Project Industry Partners


• RailTEC’s Track Loading

System (TLS) will be

used to simulate field

loading conditions in the

laboratory

• The TLS can apply up to

55 kips vertically at each

journal, and simulate L/V

ratios up to 0.6

• Most field instrumentation

setups can be replicated

in the laboratory

Laboratory Experimentation


• Instrumentation used in field and lab experimentation

will include:

– Potentiometers – displacement

– Weldable strain gauges –

rail seat loads

– Matrix-based tactile surface sensors –

pressure distribution at rail seat

– Lateral load evaluation devices – lateral load at

fastening system shoulder

Methods and Instrumentation Technologies


Field and Laboratory

Experimentation Locations

Light rail: TriMet (Portland, OR)

MetroLink (St. Louis, MO)

Heavy rail: New York City Transit (New York, NY)

Commuter rail: Metra (Chicago, IL)


• Design approach utilizing forces measured in track structure and

properties of materials that will withstand or transfer them

• Uses responses (e.g. contact pressure, relative displacement) to

optimize component geometry and materials requirements

• Based on measured and predicted response to load inputs that

can be supplemented with practical experience

• Requires thorough understanding of load path and distribution

• Allows load factors to be used to include variability due to

location and traffic composition

• Used in other engineering industries (e.g. pavement design,

structural steel design, geotechnical)

Introduction to Mechanistic Design

Define Load

Inputs

Define

Design CriteriaComponent

Design

System

Verification


Load Characterization• Load magnitude will vary according to:

– Traffic type

– Train speed

– Track geometry

– Vehicle and track health

• Each component of the input load must be considered

– Vertical

– Lateral

– Longitudinal

• A complete understanding of the input loads can lead to optimized

component and system designs

– As load magnitude and frequency change, the optimal design of

the crosstie and fastening system may change

Define Load

Inputs

Define

Design CriteriaComponent

Design

System

Verification


Rail Transit Load Environment

• Understanding of transit load environment is a

necessary first step for this project

• Internet resources were used to preliminarily quantify

vehicle weights throughout the United States

• Field experimentation will later be used to further

define load environment


Passenger Vehicle Weight Definitions

• PB Light Rail Design Handbook defines:

– AW0: Empty vehicle operating weight

– AW1 (Seated Load)

• Fully seated passenger load + AW0

– AW2 (Design Load)

• Standing passengers at 4/m2 + AW1

– AW3 (Crush Load)


– AW4 (Structural Design Load)


AW3 = Maximum Passenger Capacity

× Average Passenger Weight + AW0


AW3 Vehicle Weight Calculation

• Passenger car quantity and

capacity

• National Transit Database

(NTD)

Revenue Vehicle Inventory

– Number of active

vehicles

– Seating and

standing capacity

• Empty Car Weight

– Manufacturer

data sheets


AW3 Vehicle Weight Calculation (cont.)

• Average passenger weight:

– Light Rail Design Handbook specifies 155 lbs

– FAA specifies 195 lbs

• Considers the increase in average weight

• Includes clothing and luggage such as backpacks

Flight Standards Service. 2005. Aircraft Weight and Balance Control. Federal Aviation Administration, Washington, DC.


Light Rail, Heavy Rail, and Commuter Rail

Vehicle Weight Distribution

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 50 100 150 200 250

Perc

ent

Exceedin

g

Weight (kips)

Light Rail AW0

Light Rail AW3

Heavy Rail AW0

Heavy Rail AW3

Commuter Rail AW0

Commuter Rail AW3


Light Rail, Heavy Rail, and Commuter Rail

Axle Load Distribution

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 10 20 30 40 50 60

Perc

ent

Exceedin

g

Axle Load (kips)

Light Rail AW0

Light Rail AW3

Heavy Rail AW0

Heavy Rail AW3

Commuter Rail AW0

Commuter Rail AW3


Application: Flexural Design of CrosstiesCritical Regions for Flexure

Rail Seat Positive (RS+)

Center Negative (C-)


Flexural Analysis – MRS+ - AREMA 2014

Factor

Assumed or

Determined

Value

Crosstie Spacing (in) 30

B (8’-3” Crosstie) (in-kips) 320

A (for a 33 kip axle) 33/82=0.40

Speed (mph) 60

V 1.0

𝑀𝑅𝑆+ = 𝐵𝐴𝑉

Where: MRS+ = rail seat positive

bending moment

B = the bending moment

in inch-kips for a particular

crosstie length and spacing

A = the transit load

reduction factor

(axle load/82k)

V = the speed factor (≥1.0)

Equations and figures from Article 30.4.4.1 of the 2014 AREMA Manual



Factor

Assumed or

Determined

Value



A (for a 33 kip axle) 33/82=0.40

Speed (mph) 60

V ≥1.0 1.0



bending moment





reduction factor

(axle load/82k)





Factor

Assumed or

Determined

Value



A (for a 33 kip axle) 33/82=0.40

Speed (mph) 60

V 1.0

MRS+=BAV=(320)(0.40)(1.0) 128 in-kip



bending moment





reduction factor

(axle load/82k)




Flexural Analysis – MC- - AREMA 2014

Factor

Assumed or

Determined

Value

Crosstie Length 8’-3”

FC- 0.77

MRS+ 128 in-kip

MC- 99 in-kip

𝑀C− = 𝐹𝐶−𝑀𝑅𝑆+

Where: MC- = center negative

bending moment

FC- = center negative

factor (per AREMA Table

30-4-1)

MRS+ = rail seat positive

bending moment



Flexural Analysis – MRS+ – Proposed

• Comparison of bending moments

– AREMA 2014

– AREMA 2015 (proposed)

Crosstie Length (L) AREMA 2014 Structural Analysis

8’-3” 128 in-kip 120.5 in-kip

𝑀𝑅𝑆+ =𝑅(𝐿 − 𝑔)

8Where: g = rail seat center-

to-center distance

R = rail seat load

L = crosstie length

g

R R


Flexural Analysis – MC- – Proposed

• Comparison of bending moments

– AREMA 2014

– AREMA 2015 (proposed)

Crosstie Length (L) AREMA 2014 Structural Analysis

8’-3” 99 in-kip 99 in-kip

(for α = 0.42)

𝑀𝐶− =𝑅

2

𝐿2 − 1 − 𝛼 𝑐2

2 𝐿 − 1 − 𝛼 𝑐− 𝑔

Where: R = rail seat load

L = crosstie length

α = center support factor

g = rail seat center-

to-center spacing

c = center support

region = 2g - L

g

R R

c

Center support factor (α) currently under review in AREMA

Committee 30 (Ties)


Future Work and Path Forward

• Further expand the understanding of vehicle and

infrastructure characteristics for rail transit

– Conduct field and laboratory experimentation to

more accurately characterize the loading

environment for light rail, heavy rail, and commuter

rail transit

• Investigate maintenance equipment wheel loads to

ensure compliance in crosstie and fastener design

• Conduct a survey on the use and performance of

concrete ties and fastening systems

– Objective: Develop an understanding of the most

common types of failures and the design

requirements for optimizing component resiliency


Rail Transit Infrastructure SurveyRailTEC Researchers Need Your Help!

• Survey will assist RailTEC

researchers in prioritizing

upcoming FTA-funded

research efforts

• Questions are specific to

concrete crossties and

fastening systems

• Need light, heavy, and

commuter rail responses

• Survey should take only

10-15 minutes

• Free RailTEC mug for first

20 respondents!

Survey of Rail Transit Track

Superstructure Design and

Performance

The first 20 individuals who complete the survey will receive a complimentary

RailTEC mug shipped to the address provided in the survey!

The Rail Transportation and Engineering Center

(RailTEC) at the University of Illinois at Urbana-

Champaign (UIUC) has been awarded a grant

from the FTA titled “Resilient Concrete Crosstie

and Fastening System Designs for Light Rail,

Heavy Rail, and Commuter Rail Transit

Infrastructure”. The primary objective of this

project will be to develop new concrete crosstie

and fastening system designs used in light rail,

heavy rail, and commuter rail infrastructure that

take into account their unique loading conditions.

The RailTEC team, along with its Industry

Partners (listed on right), is conducting a survey to

help determine the most critical aspects of

crossties and fastening systems that should be

made resilient in the face of natural disasters or

other events that place increased stress on

infrastructure and its components. We invite you

to participate in this survey at the following link:

https://goo.gl/QVJuyB

Survey results will be used to guide the field and

laboratory experimental efforts as well as the

analytical finite element (FE) modeling

components of this project.

If you have any questions about this survey,

please feel free to contact RailTEC Graduate

Research Assistant Xiao (Sean) Lin at

[email protected].

FTA Project

Industry Partners

APTA

NYCT

(New York

City, NY)

Metra

(Chicago, IL)

MetroLink

(St. Louis, MO)

TriMet

(Portland, OR)

Pandrol USA

GIC

Amsted RPS

LBFoster, CXT

Concrete Ties

Hanson

Professional

Services, Inc.

Amtrak


Acknowledgements

• Funding for this research has been provided by:

– Federal Transit Administration (FTA) (starts 1 Aug. 2015)

– National University Rail Center (NURail Center)

• Industry Partnership and support has been provided by

– American Public Transportation Association (APTA)

– New York City Transit (NYCT)

– Metra (Chicago)

– MetroLink (St. Louis)

– TriMet (Portland, Ore.)

– Pandrol USA

– Amsted RPS / Amsted Rail, Inc.

– LBFoster

– GIC Inc.

– Hanson Professional Services, Inc.

– Amtrak

• UIUC Students Sean Lin and Henry Wolf

FTA Industry Partners:


Contact Information

Matthew V. Csenge

Manager of Experimentation

[email protected]

Xiao (Sean) Lin

Graduate Research Assistant

[email protected]

Henry E. Wolf

Graduate Research Assistant

[email protected]

Marcus S. Dersch

Senior Research Engineer

[email protected]

J. Riley Edwards

Sen. Lecturer and Research Sci.

[email protected]

Documents

Mechanistic Design of Rail Transit Concrete Crossties ... · •Fully seated passenger load + AW0 –AW2 (Design Load) ... Aircraft Weight and Balance Control. ... 0 50 100 150 200