After a necessary review of available methods to estimate deflection in simply supported prestressed concrete beams, this paper proposes a new method to estimate the time-dependent deflection of prestressed beams at any time during their service life. It is called the pressure-line method because it considers the beam subjected to a compressive force following the profile of the pressure line instead if that of the tendons. This method has two main simplifying characteristics, namely, (1) a single sustained loading (the pressure-line loading) comprising the combined effects of sustained external moments (dead load moments) and prestressing moment is considered and (2) a lump sum estimate the total time-dependent prestress losses and its percentage values with time are assumed a priori. The proposed method applies to prestressed and partially prestressed concrete beams assumed uncracked under their sustained load. Although it requires minimal computational effort, a design chart is provided to simplify its implementation.
