An explicit model for exposed column base connections and its parameter sensitivity

Exposed column bases are the connection type most often employed in low to mid-rise steel moment resisting frames. Design typically follows idealized conditions for their boundaries, i.e. either pinned or fixed. In truth, the bases' behavior falls between those two cases and, depending on their design, can have important system-level seismic performance implications. The main objective of this paper is to present the details of a recently developed modeling approach for exposed column bases and help guide its use. It will start by briefly reviewing the chief factors involved in the hysteretic response of these connections. After, an explicit mechanics-based model is presented in which each component of the base is individually simulated. Sensitivity studies on features such as material modeling parameters as well element discretization levels are then conducted to assess the model’s performance. Recommendations are made on its effective use, as are remarks pertaining to its limitations.