Seismic performance of damaged frame retrofitted with self-centering and energy-dissipating rocking wall

Abstract

This paper proposes the novel concept of retrofitting damaged reinforced concrete frame with self-centering and energy-dissipating rocking wall. Parametric studies were carried out base on pushover and time-history analysis. In both pushover and time-history analysis, the soft-story mechanism was effectively mitigated through the rocking wall retrofit of the damaged structures. The results demonstrated that the stiffness and bearing capacity of the retrofitted system were improved compare to its intact state. Additionally, the seismic response of the damaged frame retrofitted using rocking wall in combination with post-tension and shear-type damper fell within the relevant design limits. Pushover analysis of the rocking wall indicated that there is a linear relationship between the wall thickness and the initial stiffness of the retrofitted system. The addition of post-tension tendon to the rocking wall system enables the wall to self-center and increases lateral stiffness and bearing capacity of the retrofitted system. When the shear-type damper was installed, the energy dissipation of the system was increased, and the stiffness and bearing capacity of the retrofitted system were also improved. In the time-history analysis, it was found that the thickness of the rocking wall is directly related to the maximum inter-story drift and the distribution patterns of inter-story drift of the frame. As the post-tension was added to the system, the maximum inter-story drift under rare earthquake excitation improved significantly. With the addition of shear-type dampers, the overall drift magnitude of the retrofitted system was fundamentally decreased.

Keywords

• Rocking wall
• Damaged frame retrofit
• Post-tensioning
• Shear-type damper