System Identification of Degrading Hysteretic Restoring Forces of Reinforced Concrete Frames
Date Issued
2009
Date
2009
Author(s)
Huang, Jhih - Ren
Abstract
Building structures usually exhibit nonlinear and inelastic behavior under severe dynamic loading such as earthquakes, severe winds, and waves. Inelastic behavior often manifests itself in the form of a hysteresis loop, when the structure is subjected to a cyclic load. Hysteresis refers to the hereditary and the memory nature of an inelastic system, in which the restoring force depends not only on the instantaneous deformation but also on the past history of deformation. The most important, the performance and safety of reinforced concrete structures under severe earthquake loading depend on nonlinear hysteretic behavior. total of six reinforced concrete frames, designed with the same dimensions and the same seismic design code, subject to different level of ground excitation individually from shaking table test. Cyclic loading curve of each frame after the ground excitation from shaking table test was also generated to examine the remaining capacity of each frame. The modified Bouc-Wen hysteretic model was used and the system identification process was applied on the shaking table test data to identify the physical parameters such as stiffness degradation, strength deterioration and pinching hysteresis behavior of the reinforced concrete frame. The stiffness and strength degradation of RC frame in relating to the level of ground shaking and damage situation are discussed. n this study, the differential evolution (DE) method was used as the system identification method to identify the optimal time-varying parameters of the nonlinear hysteretic model. The characteristics of the structure nonlinear behavior under different intensity level of earthquake loading were evaluated and the Park and Ang damage indices were also generated. The relationship between the damage index and the system hysteretic behavior was studied. As a result, it may efficiently grasp at the degradation of the reinforced concrete frame through the hysteretic parameters of the Bouc-Wen model.
Subjects
System identification
differential evolution algorithm
stiffness degradation
strength degradation
pinching effect
Type
thesis
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