I am using LEAP Steel and LEAP Concrete to model a 4-span, continuous steel bridge on a 2-column pier system. This is an existing bridge undergoing rehab. and columns are on isolated spread footings. I wish to treat the columns as partially fixed, which involves inputting the desired spring constants KxKx, KyKy, and KzKz, and Rx, Ry, and Rz. Where might I find information to accurately determine these spring constant based on my type of soil/rock that the footings rest on? Thank you for any help.
The K value is used to check if the effect of slenderness needs to be considered for the column design.