Tendons need to be considered as an external load for some purposes and as an internal force for other purposes. It is important that the tendon treatment be consistent throughout a calculation.

RAM Concept always considers tendons as internal forces in strength calculations. The full force of the tendon is an internal force, while any hyperstatic effects generated by the tendons are considered as external forces. The balance loading should never be included in load combinations used for strength calculations, while the hyperstatic loading should always be included (as an external load) in strength calculations.

RAM Concept always considers the initial prestress in tendons as external forces in service calculations. Changes in the tendons stress (from effective stress levels) – if any – are considered as internal forces. For example if a bonded tendon is stressed with a final effective stress of 175 ksi (1207 N/mm²), but applying the service loadings to the structure results in a stress increase to 185 ksi (1276 N/mm²), then RAM Concept will consider the 10 ksi (69 N/mm²)stress change as an internal force, while the 175 ksi (1207 N/mm²) initial stress is assumed to be considered in the applied loads. For this reason, the balance loading should always be included in load combinations used for service calculations, The hyperstatic loading should never be included in service calculations.