Mohammad Amir SHERAFATI - PhD. candidate, Sistan and Baluchestan University, Zahedan, Iran
Ali Reza MAHDIZADEH - PhD. candidate, TarbiatModarres University, Tehran, Iran.

An advantageous method for retrofitting of brick unreinforced masonry buildi ngs is center core. In this method vertical holes with given intervals are perforated through the brick walls to the footing and then reinforcing steel bars are embedde d in the holes and grout will be injected finally to create bond strength between wall and bars. This method would not affect inner and outer appearance of the building; therefore it would be suitable for historical bu ildings. It could be also achieved without thorrough evacuation of the building from residents and furniture. However, the difficulty of conducting such deep boreholes in weak and thin brick walls especially of older buildings remains a serious challenge in th e method. So a practical investigation was designed to inv estigate the feasibility of the method and deve lop the techniques and equipment needed. This article aim s to report the results of the experiment. Howev er, the main contribution of the study has been finding new drilling techniques, designing and testing of the best suited drilling bit which is particularly appropriate for boring brick walls without deterioration and cra cking.

Center Core Retrofitting, Brick Masonry Buildings, Boring Brick Walls, Bit