Abstract
We proposed a new retrofitting element to externally retrofit existing concrete buildings. The proposed element consists of a monolithic steel column and steel beams at each story level, and looks like a tree. The tree-shaped element is connected to the exterior of the building through studs and anchors distributed only along the length of the beams, and the steel column is free from the existing building.
Three retrofitted column specimens and four indirect connection specimens were tested. The effectiveness of the proposed retrofitting element and the mechanical properties of the indirect connection were discussed and investigated.
