An automated health monitoring system for large civil structural systems.

摘要

All over the world civil structures are assuming a more important role in modern life. As their importance increases, the need for replacing functionally absolute and/or structurally deficient civil structures also increases. This phenomena is occurring all over the world, including the CTSA and countries in Southeastern Asia. Repairing or replacing these structures will cost billions of dollars. Detecting material and structural damage early will guarantee tremendous savings in repair costs and helps prevent the unnecessary closing of traffic. A monitoring system is needed not only to detect structural damage but more importantly to determine when the structure reaches a critical state. Thus, a good monitoring system will minimize property damage and will decrease accident related deaths.; Recent works in the field of structural dynamics have shown that damage detection techniques utilizing parameters like mode shapes, modal frequencies and damping ratios can be used to identify damage in structural systems. In order to utilize them for monitoring systems, it is important to be able to establish a baseline model for the structure first and then a model updating technique can be utilized to evaluate the condition of the structure from time to time. A technique obtaining a base line model for a long span bridge has been established.; It is extremely important to minimize the number of sensing operations in large civil structures required to monitor the structural system. A Kinetic Energy Optimization technique (EOT) is derived, and numerical issues are addressed, and applied to real experimental data using an asymmetric long span bridge. Using experimental data from the bridge model, the algorithm proposed in this dissertation is compared to an Effective Independent algorithm (EIM) which optimizes the transducer placement for identification and control purposes. Existing damage identification algorithms have been applied to data from a model bridge to verify the efficiencies of different damage detection schemes.; A global structural dynamic monitoring system which is taken into consideration of the optimal transducer placement, structural integrity, and optimal structural identification was developed to automatically monitor health of the structural system.