pnu’s apm unsymmetrical beams | minimizing distortion The premise: Minimizing distortion for doubly unsymmetrical beam sections When subjected to gravity loads such as their own weight, doubly unsymmetrical sections are subjected to vertical and transversal displacements. Moreover, under pre-stressing, loading the same kind of displacements and the possibility of axial displacements can also occur. To minimize distortion (bowing), only allowing for vertical camber and eliminating lateral displacements, the pre-stressing strands should be arranged so that under their own weight, and prestressing forces (case of load transfer) the final lateral displacement across the beam is minimal. This can be achieved if, at transfer, the final orientation of the neutral axis is horizontal at all critical beam cross sections. 3