...
Transfer Forces to Substructure[Yes/No]: If the user chooses to connect to the substructure, a two-node spring is generated between the pier cap and the girder. On the other hand, if the transfer to the substructure is selected as no, a single node spring with specified fixities is generated instead. In general, selecting "no" for transferring forces to the substructure and using a single-node spring aids the user in comprehending the behavior and designing the superstructure without modeling the substructure.