MECHANICAL PRORERTIES OF EXPOSED COLUMN BASE CONNECTIONS FOR L-SHAPED COLUMNS FABRICATED USING CONCRETE-FILLED STEEL TUBES

Abstract

The response of exposed column base connections for L-shaped column is investigated through finite element analysis (FEA) in this paper which is affected by complex interactions among different components. Three finite element models are constructed to simulate the response of these connections under axial and cyclic horizontal loading, which interrogate a range of variables including anchor rod strength, base plate size and thickness. The results of the simulations provide insights into internal stress distributions which have not been measured directly through experiments. The key findings indicate that thicker base plates tend to shift the stresses to the toe of the base plate, while thinner plates concentrate the stresses under the column flange. Base on the analytical results, a hysteretic model is proposed to describe the cyclic moment-rotation response of exposed column base connections. The core parameters used to define the backbone curve of the hysteretic model are calibrated through configurational details. The comparison between the simulation and the calculated values indicates that the hysteretic model is suitable to characterize the key aspects of the physical response, including pinching, recentering and flag-shaped hysteresis phenomenon. Limitations of the model are outlined.