The connection between the seismic reinforcing element and existing building is generally inserted with non-shrinkage mortar through forced injection. This engineering method using brittle non-shrinkage mortar is expected to have an impact on the building’s seismic performance since the connection is likely to fail before a seismic reinforcing element takes effect when subjected to repetitive seismic loads. Also, the bar arrangement detail of the connecting part is complicated due to stirrups and shear reinforcing bars. To solve these problems regarding structure and constructability of the connection, the strain hardening cement composite (SHCC) was utilized and the seismic performance of the connection subjected to repetitive loads was evaluated. The results are summarized as follows:

1. The property evaluation on hybrid strain hardening cement composite made with the mixture of two different types of fiber indicated that the direct tensile strength was 1% or higher. For the PESF mixture, the figure was 3MPa or higher, and for the PEPVA mixture, it came relatively high at 4MPa or higher.

2. The comparison of specimens in terms of load-displacement relations revealed that the specimen with SHCC had an excellent deformation capacity. As the ultimate fracture patterns were compared, it was found that the specimen of SHCC mixture had better dispersion with multiple cracks than that of mortar mixture.

3. With regard to the accumulated energy dissipation and stiffness reduction, the SHCC mixture demonstrated excellent accumulated energy dissipation. And the PESF mixture indicated much better accumulated energy dissipation than the PEPVA mixture. It was estimated that the high accumulated energy dissipation of PESF mixture was because of the nature of steel fibers that were subjected to loads in both positive and negative directions.

4. In the examination on the deformation capacity of steel bars and stirrups subjected to loads, the mortar specimen tended to have significant deformation in stirrups and shear reinforcing bars while the SHCC specimen tended to have relatively little deformation there.

5. The equation of indirect connections suggested by the General Building Research Corporation of Japan was used to compare the theoretical values and experimental values. The results revealed that the estimated value and experimental value were not similar for the specimen of series 1 using hoop reinforcement. This is supposedly because the equation did not take into account the strength of the specimen. Thus, there is a need to develop an equation factoring in the cement matrix and differences in its strength.