Structural Health Monitoring of the Golden Gate Bridge
Sukun Kim, Shamim Pakzad, David Culler, James Demmel, Gregory Fenves, Steven Glaser, and Martin Turon
A Wireless Sensor Network (WSN) for Structural Health Monitoring
(SHM) is designed, implemented, deployed and tested on
the 4200ft long main span and the south tower of the Golden Gate
Bridge (GGB). Ambient structural vibrations are reliably measured
at a low cost and without interfering with the operation of the bridge.
Requirements that SHM imposes on WSN are identified and new
solutions to meet these requirements are proposed and implemented.
In the GGB deployment, 64 nodes are distributed over the main
span and the tower, collecting ambient vibrations synchronously at
1kHz rate, with less than 10us jitter, and with an accuracy of 30uG.
The sampled data is collected reliably over a 46-hop network, with
a bandwidth of 441B/s at the 46th hop. The collected data agrees
with theoretical models and previous studies of the bridge. The
deployment is the largest WSN for SHM.
Researches
Software: Sentri - Structural Health Monitoring Toolkit
Hardware Information, under Mica Sensorboards as Mica GGB/Accel Board
Papers
Health Monitoring of Civil Infrastructures Using Wireless Sensor Networks, Sukun Kim, Shamim Pakzad, David Culler, James Demmel, Gregory Fenves, Steven Glaser, and Martin Turon, In the Proceedings of the 6th International Conference on Information Processing in Sensor Networks (IPSN '07), Cambridge, MA, April 2007, ACM Press, pp. 254-263.
Multi-Purpose Wireless Accelerometers for Civil Infrastructure Monitoring, Shamim N. Pakzad, Sukun Kim, Gregory L Fenves, Steven D. Glaser, David E. Culler, and James W. Demmel, In the Proceedings of the 5th International Workshop on Structural Health Monitoring (IWSHM '05), Stanford, CA, September 2005, ed. F-K Chang, pp. 125-132.
Posters
Poster Abstract: Wireless Sensor Networks for Structural Health Monitoring, Sukun Kim, Shamim Pakzad, David Culler, James Demmel, Gregory Fenves, Steve Glaser, and Martin Turon, The 4th ACM Conference on Embedded Networked Sensor Systems (SenSys '06), Boulder, CO, November 2006, (poster)
Presentations
Health Monitoring of Civil Infrastructures Using Wireless Sensor Networks - Sensor Network Architecture meeting (Nov 2006)
Details
Hardware
Hardware Block Diagram. Details of two accelerometers
(ADXL 202E and SD 1221L) are in the table below. A thermometer
is used for temperature calibration.
Accelerometer Board. ADXL 202E has two axis in a
single chip. Either Mica2 or MicaZ can be used as a mote.
Software
Overall Software Architecture
Deployment
The Golden Gate Bridge and layout of nodes on the
bridge. To cover this large bridge, long linear topology needs
be used, and it brings challenges to the network.
Board enclosure, antenna, and battery installed on
the main span. The zip tie had to be put around the antenna to
control wind vibration. Poor link quality was experienced with
vibrating antenna under strong wind. Corrosion of C-clamp
can be observed in the figure.
Results
Bandwidth of Straw at the Golden Gate Bridge. It
works over a 46-hop network. To sustain high bandwidth over
a long path, pipelining is used avoiding interference.
Time and Frequency Plots of Transverse (Horizontal)
Sensor Located at Quarter span, 365m North of the South
Tower. The data matches the fundamental frequency of the
bridge in past studies.
Transverse (Horizontal) Sensor, Mid-Span
The vertical modal properties match among simulation
model, previous study, and this study.
Torsional modes also match.
* This work is supported by the National Science Foundation under Grant No. EIA-0122599 and by the Center for Information Technology Research in the Interest of Society (CITRIS).