Abstract
A large numbers of steel roof bearings in RC gymnasia are damaged at 2011 Tohoku Earthquake, and out-of-plane response of cantilevered RC walls supporting the roof frame is identified as one of main causes of damage. In order to use these gymnasia as shelters after the earthquake, they are required seismic retrofit. However, a conventional seismic retrofit method requires strengthening bearings with steel corner plates and replacing all the roof braces, which is uneconomical. In this paper, a seismic retrofit method inserting energy-dissipation elements into roof bearings is discussed and their response reduction effects on the gymnasium are investigated. Furthermore, a simplified response evaluation method using equivalent SDOF system and equivalent linearization technique are proposed to determine the optimum design of the energy-dissipation bearings.
