Resumen
There is a problem of simplified of computational models, which are used at calculation and designing of metal superstructures as a frame. Sometime it leads to the considerable errors in calculations. In this work researches of dimensioned behavior of a superstructure by a finite element method was implemented. In the capacity of calculated construction the standard superstructure (a type project ?690/2) has been used. Ground obtained results the model for calculation of supplemental forces in chords was designed, which simulate a behavior of constructional.