PREDICTION METHOD FOR MOMENT-ROTATION BEHAVIOR OF EXPOSED-TYPE STEEL COLUMN BASES UNDER BI-AXIAL BENDING

It has already been proved that assuming them as pinned or fixed supports is not a suitable way to simulate their actual behavior because in most cases, column bases have strong semi-rigid behavior highly affecting the overall behavior of the structure. In order to reflect the column base behavior to the frame design work, the column base can be modeled as a kind of semi-rigid and partial strength connection with plastic rotation capacity. In this paper, standard M-θ skeleton curve of exposed-type column base and estimation method on inelastic behavior under bi-axial bending is proposed. Also, a method to simulate the inelastic behavior of column base in case of biaxial bending by expanding uni-axial restoring force characteristic model to bi-axial model is proposed, anchor bolt yielding type and base plate yielding type respectively