Influence of Hysteretic Behavior on the Nonlinear Response of Frame Structures

This paper focuses on understanding and assessing the effect of hysteretic behavior (i.e., bilinear, peakoriented and pinching) in the evaluation of peak deformation demands and their distribution over the height for regular frame structures over a wide range of stories (from 3 to 18) and fundamental periods (from 0.3 s. to 3.6 s.). The ground motions used are those with frequency content characteristic of ordinary ground motions (no near-fault or soft soil effects). The hysteretic models utilized in this study do not exhibit monotonic or cyclic deterioration; thus, the discussion is most relevant for performance levels related to damage and loss of functionality. Results suggest that the degree of stiffness degradation is important for the seismic performance evaluation of regular frames because systems with a large degree of stiffness degradation tend to exhibit larger peak drift demands and a less uniform distribution of peak drifts over the height. The type of hysteretic behavior also has a significant influence on the dynamic response of long, flexible frames that are prone to global dynamic instability due to P-Delta effects. This study also demonstrates the need to develop reliable procedures to estimate the properties of “equivalent” or “reference” SDOF systems when they are used to evaluate the response of complex MDOF structures with various hysteretic responses at the component level.