Seismic retrofit of masonry wall infilled RC frames through external post-tensioning

In this study, an external post-tensioning technique was employed to enhance the seismic performance of infilled RC frames through preventing premature failure of infill walls and increase in their engagement with RC frames. Totally, six 1/3-scale single-story single-bay RC frames were constructed and tested. The frames were divided into two groups based on their aspect ratios. Each group consisted of a bare frame, an infilled frame and a retrofitted infilled frame. All specimens were subjected to a similar quasi-static cyclic loading and their responses were measured through load cells, strain gauges and linear variable differential transformers. Results indicated that the retrofitted infilled frames had higher initial stiffness, ultimate lateral strength and ductility ratio when compared with the bare and un-retrofitted infilled frames. The retrofitted infilled frames also showed a prolonged failure mode and a lower stiffness degradation rate compared to other frames. It was also observed that, compared to other frames, the retrofitted frames had smaller strain values at their critical zones.