The practice of bridge construction has shown that the service life of small bridges is 2-3 times less than large ones. The monograph identifies the reasons for their low durability. New structural and technological solutions of small bridges with high technical and economic indicators are proposed. They are based, in particular, on the rejection of expansion joints, which are the "pain point" of any bridge structure. Another classification of bridges is physically justified, where the areas of application of small seamless and large bridges are clearly indicated. For students and teachers, as well as everyone interested in the problems of building bridges.