Earthquake Response Control for Civil Structures

In contemporary civil engineering, performance analysis for the dynamic response of structures due to transient environmental loads constitutes a standard part of the design process. Acceptable structural designs must be resilient in the face of earthquake and wind disturbances, as well as blast loads. Considerable uncertainty exists regarding these loads, in terms of their arrival times, as well as their frequency content, intensity, and time duration. Beginning in the 1960s, structural engineers began adopting vibration isolation concepts and technologies, which had first emerged primarily in the aerospace sector, to design supplemental passive mechanical components of structures for the suppression of dynamic response. These included several basic concepts which have since been embraced and implemented in many structures around the world. Most prevalent among these is the installation of highly flexible base isolators in low-and medium-rise buildings. Such systems have been shown to be highly effective at mitigating large accelerations and deformations in the superstructure during earthquakes, and their implementation is becoming standardized in the industry. In high-rise buildings, supplemental tuned mass dampers (usually installed at or near the top floor) have gained acceptance as a technique for reducing structural accelerations due to wind loads. Figure 30.1 illustrates an idealized building structure "73605_C030" - #2 incorporating both a base-isolation system and a tuned mass damper. Additionally, many tall buildings around the world have been fitted with ancillary dissipative damping mechanisms, such as hydraulic or friction dampers installed between stories to dissipate energy.

Duke Scholars

Author Henri P. Gavin Civil and Environmental Engineering