A novel technique for the retrofitting of reinforced concrete structures

A novel technique to enhance the seismic behaviour of existing RC framed structures is proposed. The technique is based on the introduction of friction devices in the vicinity of the expected plastic hinges in the original structure. The proposed technique is applied to an existing RC soft storey building. Static and dynamic timehistory nonlinear analyses are conducted on a simplified model. The efficiency of the proposed upgrading technique is evaluated in terms of strength, stiffness and energy dissipation. A comparison between the behaviour of the original and the upgraded structures shows that the proposed technique is effective in reducing seismic vulnerability. Most of the hysteretic energy is dissipated by friction in the added devices, rather than by damage in the members of the structure. The proposed technique is less invasive than conventional upgrading methods such as steel bracing systems with supplemental damping devices.