[en] Geometrical misaligned elements cause displacement of the beam center from the ideal accelerator axis and an increase of the beam radius, which are discussed in some detail in the literature. For any quasiperiodic accelerating structure and independent statistical distributed displacement errors of the single elements, a formalism is presented by which both effects can be calculated. The obtained rms radius increase is almost independent of the beam current. The optimal position for steering magnets can easily be determined. As an example, the radius increase is plotted as a function of the beam energy for the SNQ 324 MHz disk-and-washer proton linac. The main effect here is the transverse displacement of a single quadrupole in a doublet. Rotations of quadrupoles about the beam axis and field errors are negligible. With 5 pairs of steering magnets, the shift of the beam center away from the ideal axis is less than 5 mm everywhere