STUDY ON CONCEPT AND CHARACTERISTICS OF SEISMIC JERK RESPONSE SPECTRA

Jerk is the time rate of acceleration, reflecting the variation of structural forces. The study on jerk and its response spectra can enhance the recognitions on the non-stationary of ground motion. The mechanical meaning and research value of jerk is described. The calculating methods for jerk are discussed and their performance and disadvantages are compared. The solution method of elastic and inelastic jerk response spectra under ground motion is established. The characteristics of jerk response spectra are studied according to the influencing factors, such as a site condition, an amplification factor, a ductility factor and a reduction factor. The concept of an impact reduction factor is presented. The analysis results show that jerk influences the building structures with short or middle periods more obviously, and the impact responses can be reduced significantly when the structural ductility is enhanced. The impact reduction factor increases with the incensement of a structural natural period and the influence of jerk on long-period structure can be ignored.