In seismic retrofitting of existing building, concrete surface are chipped using an electric chipping hammer in order to connect retrofitting members to R/C frames. The roughened concrete surface has very complex concavo-convex shape. Therefore, estimating of the shear strength is very difficult.
In this paper, we conducted the shape-measurement and shape-analysis of roughened concrete. In addition, the shear tests are also conducted. Using the obtained data, we tried to evaluate the shear strength as sum of strength by bearing stress and by local interlocking. As a result, it was concluded that the optimal area ratio rcr was about 0.3.
