| Different from traditional passive controlled structure, the rocking wall aims to control the deformation mode of a overall frame structure, by which the ideal damage pattern is realized, thus fully functioning all seismic fortification measures. Dampers will consume massive seismic input energy, effectively limiting the maximum deformation of structures. This paper studies the design method of reinforced concrete frame structures installed with rocking walls with regards to both stiffness and strength. The goal is to finding a continuum function between the demand of structure performance and the design parameters of rocking walls, thus genuinely realize the performance based deisgn procedure. The main achievements are listed as following:1. Two sets of RC frames with various stories were designed with different failure patterns, which yielding mechanism are ―beam hinge mechanism‖ and ―column hinge mechanism‖. Fishbone model were built in Open Sees to verify its applicability in simulating the seismic response of multistory RC frames by pushover analysis, time history analysis and IDA analysis.2. Based on the elastic fishbone model, the relationship between the stiffness ratio of horizontal members and vertical members and the deformation pattern of structure is proposed. Because columns and rocking walls are essentially the same in terms of controlling the deformation mode. The possibility to simulate a rocking wall frame structure by use of the fishbone model was demonstrated and validated in both elastic and plastic analyses. On this basis, parametric analyses were conducted considering the ideal yielding mechanism exactly formed. Finally, a method for determining the stiffness requirements of rocking walls were proposed.3. In order to examine the effectiveness of rocking walls in controlling the deformation mode of a RC frame structure, a parameter which stands for the first mode stiffness ratio was applied. 26 ground motions with pulse-like components and 26 motions without pulses were selected for the IDA analyses. The influence of stiffness ratio to the deformation, hinges rate, and structure bearing capacity were investigated. It shows that when the stiffness ratio is larger than 3, the frame structure can form ideal yielding mechanism. The response of rocking wall frame structures subject to ground motions with pulses is more serious than those without pulses.By means of pushover analysis and the IDA analysis using one typical ground motion only, it shows that if the intensity grows higher and the stiffness ratio becomes bigger, the internal force of rocking wall produced by advanced mode can’t be ignored. The statistical analysis indicated that the growth of internal force in rocking wall is smaller than the growth of bearing capacity when the stiffness ratio is relatively high. The envelope of internal force distribution of rocking wall is the similar as the deformation of a pin-supported beam subjected to a uniformly distributed load.5. Through time history analysis, the stiffness, strength, distribution and hysteretic characteristics of dampers in a rocking wall frame structure were studied. The results demonstrate that the stiffness of the damper has little impact on deformation and internal force of structure. The max drift ratio significantly decreases with the increase of the damper’s strength, but the internal force will increase accordingly. Dampers evenly placed at both sides is better than thoseconcentralized at the bottom. Dampers with self-centering force-displacement relationship are able to sharply decrease the residual displacement of a structure. |
