The present article has been devoted to development and improvement of method used for numerical modeling structures of containment prestress system (CPS) tendons via functions of finite element (FE) forms of «irregular» prism, hexahedron, providing sufficiently effective approximation of the volume model and more improved interpolation of rope nodal efforts, along with fast algorithm of operation.

The article presents main provisions of the mathematical apparatus, being a basis of the method; force vectors' interpolation examples are given for separate finite elements and the prestressed containment whole model. CPS is calculated as per the AES-2006 design, and the calculation results are compared using interpolation method of tetrahedron form functions and «irregular» prism form functions; the major prerequisites are set forth for subsequent development of prestressed tendons modeling method, considering the more sophisticated physical-mechanical phenomena and real performance of containment structure. 

The produced method outcome is the author's developed domestic software complex, allowing with sufficient accuracy to carry out calculations and modelling of the CPS, considering arbitrary spatial trace of tendons within the containment, giving reply to the main questions: whether is the minimum level of compression sufficient and whether is the operational suitability of a structure provided?