Real time damage assessment using fiber optic grating sensors Sean Calvert *a , Joel P. Conte **b , Babak Moaveni b , Whitten L. Schulz a , Raymond de Callafon c a Blue Road Research; b Dept. of Structural Engineering, c Dept. of Mechanical & Aerospace Engineering, University of California, San Diego ABSTRACT Over the past few years Blue Road Research and the University of California at San Diego have been collaborating to develop a bridge health monitoring system using long gage length fiber optic strain sensors and modal analysis. Two programs supporting this effort have been funded by the National Science Foundation and from this work several papers have been published showing its strong progress 1-5 . In 2002, the Federal Highway Administration and Caltrans performed a full-scale test on some of the components that will be used for the planned I-5/Gilman Advanced technology Bridge in California, USA. As a part of this test Blue Road Research used its developmental system to validate the use of this damage detection technique and to compare the results with conventional modal analysis tools. Keywords: Macroscopic strain, dynamic strain measurements, system identification, modal analysis, structural damage detection 1. I-5/GILMAN ADVANCED TECHNOLOGY BRIDGE The I-5/Gilman Advanced Technology Bridge currently in planning consists of a 137m (450 ft) long cable-stayed bridge supported by a 59m (193 ft) high A-frame pylon (Figure 1). This bridge utilizes fiber reinforced polymer composite materials. In order to validate the design and evaluate the performance of the I-5/Gilman Advanced Technology Bridge, a Validation Test Program was conducted in the Charles Lee Powell Structural Research Laboratory at the University of California San Diego. The objectives of this prototype test program were to evaluate the manufactured FRP components at the material level, through coupon testing and other non-destructive techniques on the members, and at the element level on full-scale component, connection, and system tests 6 . Figure 1. Elevation of I-5/Gilman Advanced Technology Bridge 6 * sean@bluerr.com; phone 1 503 667-7772; fax 1 503 667-7880; http://www.bluerr.com; Blue Road Research, 376 NE 219 th Ave, Gresham, OR 97030-8419 ** jpconte@ucsd.edu; phone 1 858 822-4545; fax 1 858 822-2260; http://kudu.ucsd.edu; University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0085