Many steel building structures were damaged in the Hyougo-kenn Nanbu Earthquake 1995.1.17 (so called Kobe Earthquake). Some restoration techniques were applied to the medium or slight damaged buildings to re-use.

These restoration techniques were surveyed with cooperation by the Building Contractors Society. From the survey, it is found that not the up-grading but the repairing were the main object for the restoration works, and the applied works had not sufficient experimental verification or literature survey.

The structural problems of exposed steel column base construction method were picked out. Three types of strengthening I repairing methods for this construction method were experimentally evaluated, i.e., steel plate jacketing type work for strengthening, steel shear plate type work and reinforced concrete cladding type one for repairing. From the loading tests before restoration and after restoration, it was clarified that these restoration works have a sufficient effect on the strength of the steel column bases.