0 0.5 1 1.5 2 2.5 3 3.5
0.16
0.18
0.2
0.22
0.24
0.26
0.28
Depth of the Notch (mm)
Am
plitu
de
of E
nve
lop
e C
urv
e (
V)
Sampling Rate = 2MHz
Next-Generation Wireless Bridge Weigh-in-Motion (WIM) System Integrated with
Nondestructive Evaluation (NDE) Capability for Transportation Infrastructure Safety
Yang Wang a, Laurence J. Jacobs a, Jin-Yeon Kim a, Nasim Uddin b a School of Civil and Environmental Engineering, Georgia Institute of Technology
b Department of Civil, Construction, and Environmental Engineering, University of Alabama Birmingham
Introduction
Motivation
Project Background Wireless Unit Development Bridge WIM
Wireless WIM+NDE Development
This project seeks to develop a low-cost wireless WIM (weigh-
in-motion) + NDE (nondestructive evaluation) system as a
solution to the transportation infrastructure safety problem in a
novel two-fold approach: control of overloaded trucks and
safety assessment and monitoring of transportation
infrastructure. The system contains individual wireless sensing
nodes that integrate state-of-the-art WIM technology and
ultrasonic NDE functionality. The result will be a transportation
infrastructure monitoring and protection system that is highly
portable, effective, and operation will require little manpower.
The main components of this system include: 1) a wireless
sensing system for real-time data acquisition and online
delivery; 2) tools for data analysis and interpretation; and 3) a
database for storage and archival.
Subject GPA Comments
Roads D ● Poor road conditions cost each US motorist
$324 per year in repairs and operating costs
Bridges C+ ● One in nine of nation’s bridges rated as
structurally deficient
Dams D ● More than 4,000 deficient dams, including
2000 deficient high-hazard dams
ASCE 2013 Ratings on America’s Infrastructure
I-35W Bridge Collapse, Minnesota
August 2007 (13 Casualties)
Teton Dam Collapse, Idaho
June 1976 (Damage: $2 billion)
Basket Lift Extensive Climbing Rigging
Current Practice for Bridge Inspection
Communication Network: from Wired to Wireless
Wireless
Sensor Units
Embedded
Sensors
Central Data
Server (CDS)
Coaxial Cables
Installation of wired system can take about 75% of total testing
time for large structures. (Straser and Kiremidjian, 1998)
$5,000 per sensor channel, half of the cost on cabling and labor.
(Celebi, 2002)
0.5mm
1.2mm 3.2mm
2.3mm
Steel specimen with
different notch depth
Diffuse ultrasonic NDE for
concrete specimen
Wedge ultrasonic transducer
Concrete bridge
component
Transmitter Receiver
Wireless
device
Surface crack
Ultrasonic NDE
BWIM shema SiWIM Bridge
Weigh-in-motion
system
Bridge Weigh-in-Motion
Wireless unit
Ultrasonic transducer
Excitation signal conditioning Output signal
conditioning
Laboratory Experiment
Excitation signal
conditioning
Transmitting ultrasonic transducer
Receivingultrasonic transducer
Output signal conditioning
Wireless unit
0 ~ 3.3V
-10 ~ 10V
-10 ~ 10mV1.65V ± 200mV
0 0.5 1 1.5 2 2.5 3 3.5 4
x 10-5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
Time (sec)
Am
plit
ude (
V)
Cabled system (250MHz)
WSU (2MHz)
Wireless Measurement Validated by Cabled system
Sensor Signal
Digitization
Analog-to-Digital
Conversion
Computational
Core Wireless
Communication
900MHz or
2.4GHz Wireless
Transceiver
Weigh-in-
motion (WIM)
sensors
External
Memory
Micro-
Processor
Sensor Signal
Conditioning
Amplification,
filtering, and
voltage-offsetting
Output Signal
Amplification
Amplification and
voltage-offsetting
Transmitting
ultrasonic transducer
Receiving
ultrasonic
transducer
Wireless Sensing Unit
Wireless NDE
Wireless NDE Result
Comparison of two algorithms -- run 5
A2+A3GVW
A1 A2 A3 A4 A5 Single A4+A5
-50
-40
-30
-20
-10
0
10
20
30
40
50
Pe
rce
nta
ge
err
or
(%)
SiWIM algorithm Proposed algorithm item
Future: Wireless Drive-By Inspection
Drive-by bridge
inspection system Portable bridge
weigh-in-motion
Bridge safety
management
Internet
Local
gateway
Office PC
AT&T
server
GPRS
Cell phone
tower
GSM/
GPRSWireless unitWireless unit
Wireless unit
Wireless unit
