Shallow embedded steel column connections are widely used in steel buildings; however, there is insufficient research about this connection type to understand the actual rotational stiffness that the connection provides. Shallow embedded steel columns are when a steel column is anchored to the foundation slab and then unreinforced concrete is poured around the base plate and the base of the column. This thesis seeks to further quantify the rotational stiffness available in this type of connection due to the added concrete and improve an existing model in order to represent the rotational stiffness. Existing data from two series of experiments on shallow embedded columns were used to validate and improve an existing rotational stiffness model. These two data sets were reduced in the same manner so that they could be compared to one another. In addition, the rotational stiffness for each test column was determined so they could be evaluated against the outputs of the model. The existing model was improved by evaluating each parameter in the model: the modulus of subgrade reaction, exposed column length, modulus of concrete for the blockout and the foundation slab, flange effective width, embedment depth, and effective column depth. It was determined that the model was sensitive to the subgrade reaction, modulus of concrete, embedment depth and effective column depth. The exposed length was not a highly sensitive parameter to the model. Flange effective width was determined to not be needed, especially when the other parameters were altered.

Finite element models were created in Abaqus 6.14 to characterize the rotational stiffness of shallowly embedded column-foundation connections. Scripts were programmed to automate the model generation process and allow study of multiple independent variables, including embedment length, column size, baseplate geometry, concrete modulus, column orientation, cantilever height, and applied axial load. Three different connection types were investigated: a tied or one part model; a contact-based model; and a cohesive-zone based model. Cohesive-zone modeling was found to give the most accurate results. Agreement with previous experimental data was obtained to within 27%. Baseplate geometry was found to affect connection stiffness significantly, especially at lower embedment depths. The connection rotational stiffness was found to vary only slightly with cantilever height for typical column heights. Results from varying other parameters are also discussed.