Rotational capacity of exposed base plate connections with various configurations of anchor rod sleeves

This paper presents a new approach that can enhance the rotational capacity of exposed base plate connections without degrading the initial stiffness or strength of the standard configuration. By inserting a steel sleeve with a designated geometry between the base plate and the anchor rod washer, the load path between the end plate and the rod can be interrupted, promoting a more ductile response. Exposed base plate connections with various sleeve geometries are numerically investigated using a validated FE model to demonstrate the concept of the proposed method. It was concluded that the proposed sleeve system substantially enhances the rotational capacity of the exposed column bases. An elastic response consistent with standard base plate connections is maintained indicating that the proposed system is compatible with existing codified elastic design approaches without modification.