phares (bridge monitoring – security and smart …...bridge monitoring – security and smart...
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Bridge Monitoring – Security and Smart Bridges
Bridge Monitoring Bridge Monitoring –– Security Security and Smart Bridgesand Smart Bridges
Brent Phares and Terry WipfIowa State University
National Center for Wood Transportation Structures and
Bridge Engineering Center
Mike RitterUSDA Forest Products Laboratory
Bridge SecurityBridge SecurityBridge Security
l Cooperative research project initiated by the USDA Forest Product Laboratory and Iowa State University.
l A critical need identified – provide a level of protection to historic covered bridges.– Vandalism– Arson
The Need in Madison County, IAThe Need in Madison County, IAThe Need in Madison County, IA
Initial GoalsInitial GoalsInitial Goals
l Develop & demonstrate a prototype remote security system
l Assist in the preservation of important timber bridges
l “Fill” a gap in the FHWA Covered Bridge Manual.
First Generation System ConfigurationFirst Generation System First Generation System ConfigurationConfiguration
l Three types of sensing systems:– Infrared camera– Flame detector– Fiber optic temperature sensors
l Data collected and processed on-site.l Alarms sent via text message and e-
mail to ISU and emergency responders.
Infrared CameraInfrared CameraInfrared Cameral Detects both people
and firel Mounted on utility
polel “Sees” IR spectrum
rather than visible light
Flame DetectorFlame DetectorFlame Detector
l Detects presence of a flame using:– infrared– ultraviolet– visual technologies
(flicker rate, etc.)l Probability of false
alarm is very small
Fiber OpticsFiber OpticsFiber Optics
l Measures temperature changes
l Length of sensor changes with temperature
l Installed in bridge behind trusses
On-site SystemOnOn--site Systemsite System
l Data transmitted from sensors using onsite wireless network
l Software processes data from all sensors
l Records data (including images) for use by law enforcement when alert issued
NotificationsNotificationsNotifications
Current ActivitiesCurrent ActivitiesCurrent Activities
l Second generation system currently being deployed on an additional 5 bridges.
l A covered bridge security manual is currently being developed.
Development of a Smart Timber Bridge SystemDevelopment of a Smart Timber Development of a Smart Timber Bridge SystemBridge System
l Concept: A holistic approach to timber bridge management through the integration of sensors and on-board computing.
l Initially developed the scope of research needed for full development.
l Currently in the first phase of that work.
Current Objective and ScopeCurrent Objective and ScopeCurrent Objective and Scopel Objective
– Develop methods for embedding in and attaching sensors to wood members.
l Scope– Design two types of sensors packages:
» One for structural adhesion.» One to isolate the sensor from structural response.
– Construction of small scale glulam specimens that are internally and externally instrumented.
– Laboratory testing of the specimens under different loading and temperature conditions.
– Selection of the best sensor packages.– Construction of a full scale beam specimen using selected packages
and test under laboratory conditions.
Small Scale Laboratory TestingSmall Scale Laboratory TestingSmall Scale Laboratory Testing
Nine specimens tested under:l Bendingl Sustained loadingl Fast loadingl Pseudo cyclic loadingl Heat and sustained loadingl Cold and sustained loading
Structural Response PackagesStructural Response PackagesStructural Response PackagesExternal Packages:External Packages:
CC--FRP Loctite 426 RSFRP Loctite 426 RS--SS Loctite 426SS Loctite 426
ISIS--SS Loctite 4212 72HSS Loctite 4212 72H--SS Loctite 426SS Loctite 426
Internal Packages:Internal Packages:AMAM--SS Loctite 454 RSSS Loctite 454 RS--SS Loctite 426SS Loctite 426
812"
78"
812" 7
8"
212"
12"1
2"
34"
812" 81
2"
112"
14"
12"1
4" on center
18" on center
812"
112"
2"
1"
812" 7
8"
Small Scale Test SetupSmall Scale Test SetupSmall Scale Test Setup
CL
Pin connection
Roller connection
GLULAM Specimen
SATEC Table
SATEC head
Direction ofloading
12"
36"
2500 lbs2500 lbs2500 lbs
Full Scale BeamFull Scale BeamFull Scale Beam
Full Scale Beam TestingFull Scale Beam TestingFull Scale Beam TestingMid Span
31'
West End
East End
N.A.
30'
Load Location
Girder length = Span length =
DCDT on the bottom
DCDT at neutral axis
7" typical 4'-6" 4'-6" Sensors
Typical ResultsTypical ResultsTypical Results
0 100 200 300 4000
1000
2000
3000
-300
-200
-100
0
100
200
300
-300
-200
-100
0
100
200
300
[N]
Load
[lbs]
Time [sec]
Load on Side 1 West Frame East Frame0.0
4448.2
8896.4
13344.6
MOE 1600 ksi Compressive lateral Compressive midspan Tensile lateral Tensile midspan
[με] Stra
ins
[με]
Strain Sensors Side 1 West End Side 1 Mid Span Side 1 East Ead Side 2 West End Side 2 Mid Span Side 2 East End:
Typical ResultsTypical ResultsTypical Results
0 250 500 750 10000
2500
5000
7500
10000
12500
15000
-1200
-900
-600
-300
0
300
600
900
1200
-1200
-900
-600
-300
0
300
600
900
1200
[N]
Load
[lbs]
Time [sec]
Load on Side 1 West Frame East Frame
0.0
11120.5
22241.0
33361.5
44482.0
55602.5
66723.0
MOE 1600 ksi Compressive Tensile
[με] Stra
ins
[ με]
Strain SensorsSide 1
West C-FRP Loctite 426 Mid Span C-FRP Loctite 426 Est 72H-SS Loctite 4212
Side 2 West RS-SS Loctite 426 Mid Span RS-SS Loctite 426 East IS-SS Loctite 4212
Questions?Questions?Questions?
Thank you!
www.woodcenter.orgwww.bec.iastate.edu