© 2

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Inc.

Curt A. Beckemeyer, P.E.

Sr. Vice President

Applied Research Associates, Inc. (ARA)

Integrating the Rolling Wheel Deflectometer (RWD)

into Pavement Management to Support

an Effective Pavement Preservation Program

© 2016 Applied Research Associates, Inc. 2

Presentation Outline

Background

Study Objectives and Purpose

Data Collection

Pavement Management Analysis

Findings

Conclusions

New Developments

© 2016 Applied Research Associates, Inc. 3

•System

–Laser-based system

–18-kip, single-axle, dual-tire

• Operation

–Operates at posted speeds

–No lane closures

• Measurements

–Spatially-coincident method

–Averages deflections over 0.1-mile intervals

The RWD

© 2016 Applied Research Associates, Inc. 4

Key Design Features

• Trailer• Wheels• Beam

• Lasers• Calibration• Software

Laser between dual tires

Reference beam and spot lasers

© 2016 Applied Research Associates, Inc. 5

Spatially Coincident Methodology

D1 C1 B1 A1

D2 C2 B2 A2

Point 1

Point 2

L

1 meterAnchors

Anchors

A1, B1 and C1 establish the baseline for

comparison to B2, C2 and D2

© 2016 Applied Research Associates, Inc. 6

RWD Role in Pavement Management

Network-Level Project-Level

1,0

00

s o

f la

ne

-mile

s

Preservation

Rehabilitation

or

Reconstruction

FWD

Coring

Lab

Do

ze

ns

of

lan

e-m

ile

s

0

1

2

3

4

5

6

7

8

3+000 4+000 5+000 6+000 7+000 8+000 9+000 10+000

Chainage

IRI,

m/k

m

Left WP Right WP

PQI

IRI

RWD

Sample Deflection Profile

Station / Mile

RWD FWD

AC (Good)

PCC

AC (Fair)

AC (Good)

AC (Fair)

De

flecti

on

, m

ils

PCC

35

0

© 2016 Applied Research Associates, Inc. 8

FHWA Case Study - Oklahoma

• Evaluate the benefits of integrating RWD data into PMS

• Compare results with and without RWD data

– Treatment selection

– Costs

– Performance

© 2016 Applied Research Associates, Inc. 9

• Test Network

–1,000 miles (ODOT D-5)

–Primarily flexible pavements

–Wide range of functional classifications/traffic

• Data Collection

–Continuous data collection

–Averaged data at 0.1-mile intervals

–Testing duration: 4.5 days

Test Roads

© 2016 Applied Research Associates, Inc. 10

• Composition / Use

–Pavement age

–Layer types and thicknesses

–Classification, traffic (ADT)

Agency PMS Data

• Condition

–Pavement Quality Index (PQI):

Ride quality

Rutting

Distress

–Structural condition

FWD data (interstate only)

Structural rating (subjective)

© 2016 Applied Research Associates, Inc. 11

•Software

–Deighton software (dTIMS)

•Performance Modeling–Defined sectioning

–Performance models for each pavement type

•Decision Models–Decision trees → PQI, traffic, and structural condition

–3 Treatment categories → Preservation, rehab, replacement

Agency PMS Methodology

© 2016 Applied Research Associates, Inc. 12

•Evaluate multiple M&R treatment strategies

–Base strategy: PQI only

–Two modified strategies: add RWD data

•Compare results

–Costs

–Performance (in terms of PQI)

Approach

13© 2016 Applied Research Associates, Inc.

PQI Only – Treatment Matrix

REHABILITATION

Low

Traffic

Medium

Traffic

High

Traffic

PQ

I

88

75

55

80

65

35

REPLACEMENT

PRESERVATION

14© 2016 Applied Research Associates, Inc.

RWD #1 – Treatment Matrix

PQ

I

88

75

55

80

65

PRESERVATION

REHABILITATION

REPLACEMENT

Low Medium HighTraffic→RWD → L M H L M H L M H

15© 2016 Applied Research Associates, Inc.

RWD #2 – Treatment Matrix

80

60

88

75

65

55

45

Low Medium HighTraffic→

PRESERVATION

REHABILITATION

REPLACEMENT

RWD → L M H L M H L M H

© 2016 Applied Research Associates, Inc. 16

Results

Budget Scenario

Percent change in cost

(relative to “PQI Only” base case)

PQI

Only

RWD

Option 1

RWD

Option 2

Target PQI = 92 0.0% -10.6 % -11.5 %

© 2016 Applied Research Associates, Inc. 17

• RWD allows broader, more reliable use of pavement

preservation

–Identifies roads in GOOD & FAIR structural condition

–Prevent PP use on roads in POOR structural condition

•Cost savings can be significant

–In the range of 5 to 10%, in many cases

–Depends on agency’s current strategy and road conditions

Conclusions

© 2016 Applied Research Associates, Inc. 18

Recent Advancements in

RWD Technology

RWD-Vision (cameras vs lasers)

Cameras

LED LightsLED Lights

Lights

Between

Tires18-kip load

20© 2016 Applied Research Associates, Inc.

RWD-Vision, cont.

• Right Wheel Path - Laser RWD (old)

• Left Wheel Path – RWD-Vision (new)

High Speed LED based Flash

2 Camera Positions

Basic Methodology

Image 1 (undeflected pavement)

Undeflected Region

Methodology, cont.

Image 2 (same location as image 1, but under load)

Deflected

Region

Undeflected area

23© 2016 Applied Research Associates, Inc.

Stereo-Pair Image Processing

RWD-Vision deflection

profile along wheel path

centerlineRWD-Vision

deflection contour

(on pavement surface)

RWD-Vision

deflection

measurements

(in camera

images)

29.2 in

76 inches

96

in

ch

es

Area = 3.9 ft2

x

Pixels

Pix

els

Inches

24© 2016 Applied Research Associates, Inc.

Comparison with in-Pavement Sensors

0

20

40

60

80

100

11700 11800 11900 12000 12100 12200 12300

RWD 1 RWD 2 RWD 3 Accels

Ma

xim

um

Defl

ec

tio

n, m

ils

Station, feet

Thank You!