ABSTRACT

Structural vibration control technologies have been developed for civil structures to reduce excessive vibrations caused by strong winds, severe earthquakes or other disturbances, as introduced in Chapter 13. Structural health monitoring technologies have been developed for civil structures to identify their dynamic characteristics and parameters (system identification) and to detect their possible damage (damage detection). System identification can be defined as the process of developing or improving the mathematical model of a physical system using measurement data, as discussed in Chapter 7. Structural damage can be defined as changes in structural parameters which adversely affect the current or future performance of the structure, whereas structural damage detection aims to find such changes in the structure using measurement data, as shown in Chapter 12. Although vibration control systems and health monitoring systems both require the use of sensors, data acquisition and signal transmission for their implementation, the areas of structural vibration control and health monitoring have generally been treated separately according to their respective primary objectives. This separate approach is neither practical nor cost-effective if structures require both a vibration control system and a health monitoring system. This approach is also unsuitable for creating smart civil structures with their own sensors (nervous systems), processors (brain systems) and actuators (muscular systems), thus mimicking biological systems. In this regard, this chapter gives a brief review of current research on the synthesis of structural health monitoring and vibration control. The concept of an integrated system using semi-active friction dampers is first introduced. This chapter then presents an integrated procedure for the health monitoring and vibration control of building structures using semi-active friction dampers in the frequency domain. In the integrated procedure, a model updating scheme is first presented based on adding known stiffness using semi-active friction dampers to obtain the variations of the frequency response functions (FRFs) of a building between the two states and to identify its structural parameters. By using updated system matrices, the chapter then investigates the control performance of semi-active friction dampers using local feedback control with a Kalman filter for a building subjected to earthquake excitation. A damage detection scheme based on adding known stiffness by semi-active friction dampers is proposed and used for damage detection by assuming that the building suffers certain damage after an extreme event or long-term service and by using the previously identified original structural parameters. The feasibility and accuracy of the proposed integrated procedure are finally demonstrated through detailed numerical and experimental studies.