Use of the Total Station for Load Testing of Retrofitted Bridges with Limited Access
As new technologies are increasingly applied to civil infrastructure, the need for structural monitoring systems becomes more critical. Serviceability, or deflection, is very important in monitoring the health of not only a structural system, but also in analyzing the affects of a new technology applied in the field. Traditionally, Linear Variable Displacement Transducers (LVDT"s) are used to measure deflection in many filed load tests. In the field, access can easily become an issue with this instrumentation system that is truly designed for laboratory use. LVDT instrumentation for load testing typically requires several labor intensive hours to prepare for a load test in the field; the system is accompanied by wiring and expensive electronics that may not only become a safety issue but is also very sensitive to the elements. Set up is especially difficult, if not impossible, on tall bridge spans and bridge spans over water. A recent research project required serviceability monitoring through a series of load tests for several retrofitted bridges in Missouri. For these tests, surveying equipment was employed in attempt to make serviceability measurement more practicable. Until recently, surveying equipment would not have produced the accuracy required for structural monitoring use; however, manufacturers of this equipment have developed new technologies to increase the accuracy of the instrumentation. The major component used, the total station, can measure deflection accurate to 0.2 millimeters (0.0079 in.). This monitoring system is much easier to set up and use, reducing labor and time requirements. The system has almost no site restrictions. This paper will compare and contrast the total station to traditional load testing monitoring equipment (LVDT).
W. J. Merkle and J. Myers, "Use of the Total Station for Load Testing of Retrofitted Bridges with Limited Access," Proceedings of the Smart Structures and Materials 2004: Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems Conference, SPIE -- The International Society for Optical Engineering, Jan 2004.
The definitive version is available at http://dx.doi.org/10.1117/12.539992
Civil, Architectural and Environmental Engineering
Keywords and Phrases
Civil Infrastructure; Structural System
Library of Congress Subject Headings
Article - Conference proceedings
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