Testonretr of it effects of field welded beam-to-columnconnections with RC floor slab in high-rise buildings

When subjected to long period ground motions, high-rise buildings would sustain large cumulative inelastic deformations. Beam-to-column connections with RC floor slab are tested to examine the existing performance and effect of seismic retrofit of existing high-rise buildings. Four field welded beam-to-column connections are prepared in reference to the details of high-rise buildings built in 1960s-1970s. Three types of retrofit are adopted for the beam ends, namely welding along the shear plate, attachment of wing plate haunches, and attachment of a vertical haunch. For the unretrofitted connection, presence of a floor slab is attributed to the fracture in the bottom flange. The three retrofitted connections showed three different failure modes. A plastic theory is applied to interpret the resisting mechanisms, indicating reasonable correlation with the corresponding test results.