effects of partial fixity of column base connection on overall response of steel structures

fixity of column base connection plays a major role in overall behavior of steel structures. although it is usually idealized as fully pinned or fully rigid, in reality it often exhibits semi-rigid behavior. the current study investigates the nonlinear behavior of regular column base connection and assesses its partial fixity. therefore, results from analyses of several steel frames modeled with pinned or fixed ends were utilized to design column base connection. respectively each connection was modeled by nonlinear finite element method to obtain the relative rigidity of each set of connection. then, corresponding effects have been applied to steel frames to investigate semi-rigidity effects on overall structural responses. the results clearly indicate that regular column base connection behaves in a semi-rigid manner. it is shown that in cases where the column bases are classified as pinned, they often have significant rotational stiffness. meanwhile, assumedly rigid connections may exhibit considerable rotation.