The method presented here shows an exact and very expeditous approach to the analysis of shape orthotropic plane structures of the bridge type; the calculations are very clear and simple, so that the desired results are quickly obtainable. The analysis is based on the analogy to the solution of a true plate (with material orthotropy) by means of the governing Huber equation. With the presented method it is possible to take into account the lateral contraction capacity, which is expressed by a special parameter, so that the lateral contraction of the individual members and their interaction with regard to the deformations of the structure as a whole can be calculated without any difficulties. Some formulas leading to better (more correct) values of the flexural and torsional rigidities have been also given, derived by the author elsewhere; these formulas have been derived with due regard to the influence of lateral contraction, and it is shown, what errors can arise in the various phases of the calculation when lateral contraction is neglected. It appears, that the influence of lateral contraction may be of utmost importance with some of the new materials, which posses considerably high values of the Poisson coefficients (plastics, light alloys, composites, etc.).