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.

Software: Sentri - Structural Health Monitoring Toolkit
Hardware Information, under Mica Sensorboards as Mica GGB/Accel Board

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.

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)

Health Monitoring of Civil Infrastructures Using Wireless Sensor Networks - Sensor Network Architecture meeting (Nov 2006)



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.


Overall Software Architecture


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.


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).