Hi D,
SAM's bifacial module model was developed with modules mounted on the ground or a flat roof and arranged in rows in mind, based on data from arrays with up to 45 degree tilt. SAM allows tilt angles up to 90 degrees tilt angle.
Please see Marion et al. (2017) "A Practical Irradiance Model for Bifacial PV Modules" for a description of the model that you can use to evaluate whether it will work for your application. It is listed under Irradiance, Bifacial Modules:
sam.nrel.gov/photovoltaic/pv-publications.html
Best regards,
Paul.