ABSTRACT
Many methods of seismic retrofitting (Kanata & Kikuchi 2000, Kanata et al. 2003, Kei et al. 2000, Kuse 2006) have been developed considering structural types or deficiencies of those buildings. In the buildings with brittle columns, for example, the columns are wrapped with fiber-reinforced polymer to ensure column toughness. Shear walls or steel braces are used to enhance stiffness and strength for the buildings with insufficient lateral strength. Photo 1 shows a building retrofitted with a steel braces using anchorless system developed by Taisei. On a conventional way of seismic retrofit, steel braces are connected to an existing concrete frame by anchor bolts fixed in drilling holes with epoxy grouting. This method is commonly used to provide additional strength and lateral load-carrying capacity in existing substandard structures.
