The paper gives a theoretical basis and terms for calculation of static and dynamic impact of girders with semi-rigid connections of members in joints. In the existing literature calculation of line systems in which the connections of members in joints are absolutely rigid or ideally pinned has been elaborated in detail. In real structures in general, and particularly in the precast ones, connections may be partially rigid, which can have a significant impact on the change of stresses and strains in the construction. In the world there are several procedures with different approaches to the calculation of structures with semi-rigid connections, but it was proven that all of them lead to the same results. All of these approaches give experimental analysis of the results in addition to theoretical one