This paper describes the results of an experiment and the estimation of applied cement grout materials on the seismic retrofitting construction of reinforced concrete piers, where epoxy resin is generally used as an injection material. As a result, the value of compressive strength, unit weight, etc. shows no significant difference between heights, and it is stronger than that of normal concrete piers. In the two methods of construction, injection methods and dropping down, there is no difference in performance, therefore it is found out that the cheap method of dropping down is economically favorable.
Cement grout materials are heavier than epoxy resin materials. Therefore, in the construction of cement grout materials, it is necessary to take notice of the stress in steel casing. However, it is possible to use less than allowable stress by evaluating the performance of the anchor bolts and arrangement suitably.
