Long-term health monitoring of an advanced polymer composite bridge

A long-term, structural health monitoring system has been designed and installed on the firs polymer composite bridge to be built in Delaware. The system is designed to monitor and record strains and deflections of the bridge, and the temperature and humidity of the surrounding area. Two types of information are gathered, 'monitor' data and 'event' data. The monitor data records very slow gradual changes in the bridge behavior, while the event data captures the bridge response due to truck loads. The system has been on- line since June, 1998. Sample result are presented in the paper of event and monitor data. The event data shows that the transverse strain of the deck is greater than the longitudinal strain, by a factor of about 1.5, and that the absolute deflection of the deck at mid-span is due mostly to the deflection of the edge girder. Monitor data from a one month period is presented that shows the thermal variations in strain due to daily temperature changes, and the gradual, changes due to the average daily temperature. The long-term monitoring system should provide valuable data for assessing the long-term performance and durability of this unique polymer composite bridge.